a review of gas sensors employed in electronic nose applications

Research articleA review of gas sensorsemployed in electronicnose applications

K Arshak

E Moore

GM Lyons

J Harris and

S Clifford

The authors

K Arshak E Moore GM Lyons J Harris and S Clifford

are all based at the College of Informatics and Electronics

University of Limerick Limerick Ireland

Keywords

Sensors Gases

Abstract

This paper reviews the range of sensors used in electronic

nose (e-nose) systems to date It outlines the operating

principles and fabrication methods of each sensor type

as well as the applications in which the different sensors

have been utilised It also outlines the advantages and

disadvantages of each sensor for application in a

cost-effective low-power handheld e-nose system

Electronic access

The Emerald Research Register for this journal is

available at

wwwemeraldinsightcomresearchregister

The current issue and full text archive of this journal is

available at

wwwemeraldinsightcom0260-2288htm

Introduction

The human nose has been used as an analytical

tool in many industries to measure the quality of

food drinks perfumes and also cosmetic and

chemical products It is commonly used for

assessing quality through odour and this is

carried out using sensory panels where a group

of people fills out questionnaires on the smells

associated with the substance being analysed

These sensory panels are extremely subjective as

human smell assessment is affected by many

factors Individual variations occur and may be

affected by physical and mental health as well as

fatigue (Pearce et al 2003) For this reason gas

chromatography and mass spectrometry have

been employed to aid human panels to assess

the quality of products through odour

evaluation and identification and also to obtain

more consistent results However these assistive

techniques are not portable they tend to be

expensive and their performance is relatively

slow (Nagle et al 1998)

The solution to the shortcomings of sensory

panels and the associated analytical techniques

is the electronic nose (e-nose) E-nose systems

utilize an array of sensors to give a fingerprint

response to a given odour and pattern

recognition software then performs odour

identification and discrimination The e-nose is

a cost-effective solution to the problems

associated with sensory panels and with

chromatographic and mass-spectrometric

techniques and can accommodate real time

performance in the field when implemented in

portable form

Principle of operation of e-nose systems

The e-nose attempts to emulate the mammalian

nose by using an array of sensors that can

simulate mammalian olfactory responses

to aromas The odour molecules are drawn

into the e-nose using sampling techniques

such as headspace sampling diffusion

methods bubblers or pre-concentrators

Sensor Review

Volume 24 middot Number 2 middot 2004 middot pp 181ndash198

q Emerald Group Publishing Limited middot ISSN 0260-2288

DOI 10110802602280410525977

This work was conducted as part of a collaborative

project between AMT Ireland University of

Limerick and University College Cork and is funded

by Enterprise Ireland under project ref no ATRP

2002427 (Intelli-SceNT)

181

(Pearce et al 2003) The odour sample is

drawn across the sensor array and induces a

reversible physical andor chemical change in

the sensing material which causes an associated

change in electrical properties such as

conductivity (Harsanyi 2000) Each ldquocellrdquo in

the array can behave like a receptor by

responding to different odours to varying

degrees (Shurmer and Gardner 1992) These

changes are transduced into electrical signals

which are preprocessed and conditioned before

identification by a pattern recognition system as

shown in Figure 1 The e-nose system is

designed so that the overall response pattern

from the array is unique for a given odour in a

family of odours to be considered by the system

E-nose sensor response to odorants

The response of e-nose sensors to odorants is

generally regarded as a first order time response

The first stage in odour analysis is to flush a

reference gas through the sensor to obtain a

baseline The sensor is exposed to the odorant

which causes changes in its output signal until

the sensor reaches steady-state The odorant is

finally flushed out of the sensor using the

reference gas and the sensor returns back to its

baseline as shown in Figure 2 The time during

which the sensor is exposed to the odorant is

referred to as the response time while the time

it takes the sensor to return to its baseline

resistance is called the recovery time

The next stage in analysing the odour is

sensor response manipulation with respect to

the baseline This process compensates for

noise drift and also for inherently large or

small signals (Pearce et al 2003) The three

most commonly used methods as defined by

Pearce et al (2003) are as follows

(1) Differential the baseline xs(0) is subtracted

from the sensor response xs(t) to remove

any noise or drift dA present The baseline

manipulated response ys(t) is determined

by

ysethtTHORN frac14 ethxsethtTHORN thorn dATHORN2 ethxseth0THORN thorn dATHORN

frac14 xsethtTHORN2 xseth0THORN eth1THORN

(2) Relative the sensor response is divided by

the baseline This process eliminates

multiplicative drift dM and a dimensionless

response ys(t) is obtained

ysethtTHORN frac14xsethtTHORNeth1thorn dMTHORN

xseth0THORNeth1thorn dMTHORNfrac14

xsethtTHORN

xseth0THORNeth2THORN

(3) Fractional the baseline is subtracted from

the response xs(t) and then divided by the

baseline xs(0) from the sensor response

which provides a dimensionless normalised

Figure 1 Comparison of the mammalian olfactory system and the e-nose system

A review of gas sensors employed in electronic nose applications


Sensor Review

Volume 24 middot Number 2 middot 2004 middot 181ndash198

182

response ys(t) that can compensate for

inherently large or small signals

ysethtTHORN frac14xsethtTHORN2 xseth0THORN


The choice of baseline manipulation depends

on the sensor type being used the sensor

applications and also the researchers preference

However certain manipulation techniques have

been shown to be more suitable to certain

sensor types and also variations in the

manipulation techniques can occur in the

literature which will be discussed later in this

paper

Sensitivity is the measure of the change in

output of a sensor for a change in the input This

is the standard definition given for the sensitivity

of a sensor in several texts on sensor related

topics (Fraden 1996 Gopel et al 1989

Johnson 1997) In the case of e-nose sensors

the sensitivity of the sensor (S ) to the odorant is

the change in the sensor output parameter ( y)

ie resistance for a change in the concentration

of the odorant (x) as shown in equation (4)

S frac14Dy

Dxeth4THORN

However in the literature several authors use

different values to measure sensitivity usually

calculated from baseline-manipulated data

Sensors employed in e-nose systems

Gas molecules interact with solid-state sensors

by absorption adsorption or chemical reactions

with thin or thick films of the sensor material

The sensor device detects the physical andor

chemical changes incurred by these processes

and these changes are measured as an electrical

signal The most common types of changes

utilised in e-nose sensor systems are shown in

Table I along with the classes of sensor devices

used to detect these changes

Some aspects of these classes of sensors

along with several examples from each class are

explored in the following sections of this review

Conductivity sensors

Conducting polymer composites intrinsically

conducting polymers and metal oxides are three

of the most commonly utilised classes of sensing

materials in conductivity sensors These

materials work on the principle that a change in

some property of the material resulting from

interaction with a gasodour leads to a change in

resistance in the sensor The mechanisms that

lead to these resistance changes are different

for each material type however the structure

and layout of conductivity sensors prepared

using these materials are essentially the same

A schematic of a typical conductivity sensor

design is shown in Figure 3

The sensing material is deposited over

interdigitated or two parallel electrodes which

form the electrical connections through which

the relative resistance change is measured

The heater is required when metal oxides are

used as the sensing material because very high

temperatures are required for effective

operation of metal oxide sensors

Conducting polymer composite sensors

Conducting polymer composites consist of

conducting particles such as polypyrrole and

carbon black interspersed in an insulating

polymer matrix (Albert and Lewis 2000)

Figure 2 E-nose sensor response to an odorant

Table I Physical changes in the sensor active film and the

sensor devices used to transduce them into electrical signals

Physical changes Sensor devices

Conductivity Conductivity sensors

Mass Piezoelectric sensors

Optical Optical sensors

Work function MOSFET sensors



Sensor Review


183

On exposure to gases these materials change

resistance and this change is due to percolation

effects or more complex mechanisms in the case

of polypyrrole filled composites

When the polymer composite sensor is

exposed to a vapour some of the vapour

permeates into the polymer and causes the

polymer film to expand The vapour-induced

expansion of the polymer composite causes an

increase in the electrical resistance of the

polymer composite because the polymer

expansion reduces the number of conducting

pathways for charge carriers (Munoz et al

1999) This increase in resistance is consistent

with percolation theory Polypyrrole-based

composites have a more complex transduction

mechanism because the odour molecules can

cause expansion of both the insulating polymer

and the polypyrrole particles Changes in the

intrinsic conductivity of the polypyrrole

particles can also occur if the odour interacts

chemically with the conducting polymer

backbone Therefore resistance changes in the

polypyrrole-based composites are more difficult

to predict (Albert and Lewis 2000)

Carbon black based composites were

prepared by suspending the carbon black in a

solution of the insulating polymer in a suitable

solvent The overall composition of this solution

is usually 80 per cent insulating polymer-

20 per cent carbon black by weight Different

techniques have been used to apply the active

material onto the substrate which are shown in

Table II

The transducer device is usually a flat

substrate with either two parallel electrodes or

interdigitated electrodes deposited onto the

substrate surface as shown in Figure 3

However both bulk and surface

micromachining have also been used to produce

wells on silicon substrates using patterned

silicon nitrideoxide as insulation and gold

electrodes as the metal contacts The polymer is

dropped into the well using a syringe as shown

in Figure 4 (Zee and Judy 2001)

Examples of the types of substrates and

electrodes used are given in Table III along with

the electrode dimensions given in the literature

Polypyrrole-based composites are usually

prepared by chemically polymerizing pyrrole

using phosphomolybdic acid in a solution

containing the insulating polymer A thin film

coating (40-100 nm thick) is then applied across

interdigitated electrodes (typical electrode gaps

were 15mm) using dip coating (Freund and

Lewis 1995)

The fractional baseline manipulation

response is the most common method used to

record the sensor response from conducting gas

sensors (Pearce et al 2003) This fractional

baseline manipulation is referred to as the

maximum relative differential resistance

change DRRb DR is the maximum change in

the resistance of the sensor during exposure to

the odorant and Rb is the baseline resistance

before exposure

Response times may vary from seconds to

minutes as shown in Table IV and in some

cases milliseconds (Munoz et al 1999)

However typically a set of exposure cycles

is quoted for each analyte ie initial reference

gas analyte and final reference gas exposure

times The response time depends on the rate

of diffusion of the permeant into the polymer

The diffusion rate mainly depends on the nature

of the polymer permeant and the crosslinking

the concentration of the permeant and thickness

of the film and on the effects of fillers

plasticisers and temperature (George and

Thomas 2001) General response times for

conducting polymer composites are given in

Table IV

The transport properties depend on the

fractional free volume (FFV) in the polymer and

on the mobility of the segments of the polymer

chains The segmental mobility of the polymer

chains depends on the extent of unsaturation

Therefore segmental mobility is significantly

Figure 3 Typical structure of a conductivity sensor



Sensor Review


184

reduced with increased numbers of double and

triple bonds on the carbon-carbon backbone

The presence of crystalline domains can have

two different effects on the permeability of a

polymer Crystallites are generally impermeable

to vapours at room temperature and will reduce

the diffusion coefficient However crystallites

act as large crosslinking regions in terms of the

chains entering and leaving the areas around the

crystallite in which diffusion occurs (Comyn

1985) Increased defect formation and a

reduction in interlamellar links predominate

and overshadow the effect of geometric

impedance to such an extent that diffusivity

increases despite increasing crystallinity (Vieth

1991) For example in PE-grafted carbon black

chemiresistors heat treatment of the composite

improved the crystallinity of the matrix PE and

resulted in a five-fold increase in the response of

the sensor to cyclohexane vapour compared to

the untreated sensor (Chen et al 2002)

The size and shape of the penetrating

molecule affects the rate of uptake of the vapour

by the polymer where increased size of the

molecule decreases the diffusion coefficient

Flattened or elongated molecules diffuse faster

than spherical-shaped molecules (George and

Thomas 2001)

The partial pressure ie the concentration

of the penetrant gas at the gas polymer interface

affects the response of the sensor The response

is inversely related to the vapour pressure of the

analyte at the surface Low vapour pressure

compounds can be detected in the low ppb

range while high vapour pressure compounds

need to be in the high ppm range to be detected

This is due to the polymergas partition

coefficient where low vapour pressure gas

molecules have a higher tendency to inhabit the

polymer and thus can be detected at much lower

concentrations (Munoz et al 1999)

The equilibrium partition coefficient is

essentially the solubility coefficient of the

vapour in the polymer (Vieth 1991) Sensors

with constant thickness but with different

surface areas have the same response when

exposed to analytes with moderate partition

coefficients However analytes with higher

partition coefficients have higher affinity to

sensors with smaller area In this case reducing

the sensor area increases the sensitivity of the

sensor towards particular analytes Therefore

the relationship between the partition

co-efficient and the sensor geometry is an

important factor in optimising polymer

composite sensor response (Briglin et al 2002)

Table II Application techniques used to deposit carbon black based composites

Reference Polymer Coating thickness Coating application technique

Matthews et al (2002) Poly(alkylacrylate) Thin film 086mm Spray coating

Severin et al (1998) Poly(co-vinyl-acetate) Thin film 1mm Spin coating

Severin et al (2000) Poly(vinyl butyral) Thin film NA Dip coating

Figure 4 Bulk micromachined well as used by Zee and Judy (2001)

Table III Electrodes and substrates used in conducting polymer composite sensors

Substrate

Electrode

material

Electrode

dimensions

(mm)

Electrode gap

(mm)

Electrode

thickness

(nm) Reference

Glass microscope slides Gold NA 5 50-100 Lonergan et al (1996)

Glass microscope slides Gold 10 pound 10 5 50 Doleman et al (1998a)

Glass microscope slides Gold Chromium 20 pound 10 5 30 20 Doleman et al (1998a b)

Micromachined silicon wafer Gold 01 in width 05 NA Zee and Judy (2001)

Glass microscope slide Gold Chromium 18 in length 04 50 15-30 Briglin et al (2002)



Sensor Review


185

Generally composite polymers have operating

resistances of approximately 1 to 1000 kV with

sensitivities of up to 100 per cent DRRb per mg

l gas depending on the filler type particle

loading and vapour transport properties

(Partridge et al 2000) Sensitivity to

hydrophobic analytes for conducting polymer

composites were found to be one to two orders

of magnitude higher than those recorded for

intrinsically conducting polymers (Partridge

et al 2000) The polymer composites show

linear responses to concentration for various

analytes and also good repeatability after several

exposures (Severin 2000 Zee and Judy 2001)

From the above discussion it can be seen that

for high sensitivity fast response and short

recovery times it is essential that the sensor

geometry and all the associated properties of the

polymer sensing material be highly optimised

Conducting polymer composites offer many

advantages over other materials when utilised as

gas sensors High discrimination in array

sensors can be easily achieved using these

materials due to the wide range of polymeric

materials available on the market This is due to

the fact that different polymers give different

levels of response to a given odour Conducting

polymer composites are also relatively

inexpensive and easy to prepare Sensors

prepared from these materials can operate in

conditions of high relative humidity and also

show highly linear responses for a wide range of

gases (Munoz et al 1999) No heater is

required as sensors prepared from these

materials operate at room temperature This is

an important advantage with portable battery

powered e-nose systems as a heater would

significantly increase the power consumption of

the system The signal conditioning circuitry

required for these sensors is relatively simple as

only a resistance change is being measured

The main drawbacks of using conducting

polymer composites as e-nose sensors are aging

which leads to sensor drift and also these

materials are unsuitable for detecting certain

gases for example carbon-polymer composites

are not sensitive to trimethylamine (TMA) for

fish odour applications

Intrinsically conducting polymers

Intrinsically conducting polymers (ICP) have

linear backbones composed of unsaturated

monomers ie alternating double and single

bonds along the backbone that can be doped as

semiconductors or conductors (Heeger 2001)

Yasufuku (2001) describes them as p electron

conjugated polymers where the p symbol relates

to the unsaturated structure of the monomer

containing an unpaired carbon electron

These conducting polymers can be n-doped or

p-doped depending on the doping materials

used Conducting polymers such as polypyrrole

polythiophene and polyaniline as shown in

Figure 5 are typically used for e-nose sensing

The doping of these materials generates charge

carriers and also alters their band structure

which both induce increasedmobility of holes or

electrons in the polymer depending on the type

of doping used (Albert and Lewis 2000

Dickinson et al 1998)

The principle of operation for ICP e-nose

sensors is that the odorant is absorbed into the

polymer and alters the conductivity of the

polymer (Albert and Lewis 2000 Dickinson

et al 1998) Three types of conductivity are

affected in intrinsically conducting polymers

(1) The intrachain conductivity in which the

conductivity along the backbone is altered

(2) The intermolecular conductivity which is due

to electron hopping to different chains

because of analyte sorption (Charlesworth

et al 1997) and

(3) The ionic conductivity which is affected by

proton tunneling induced by hydrogen

bond interaction at the backbone and also

by ion migration through the polymer

(Albert and Lewis 2000) The physical

structure of the polymer also has a major

influence on the conductivity (Yasufuku

2001) Albert and Lewis (2000) described

how the conductivity of doped polyaniline

was greatly increased on interaction with

ethanol caused by the hydrogen bonds

Table IV General response times for conducting polymer

composites

Response time (s) Reference

lt2-4 Lonergan et al (1996)

60 Partridge (2000)

180-240 Corcoran (1993b)

20-200 Doleman et al (1998)



Sensor Review


186

tightening or restructuring the polymer into

a more crystalline shape

Intrinsically conducting polymers are generally

deposited onto a substrate with interdigitated

electrodes using electrochemical techniques or

by chemical polymerisation (Freund and

Lewis 1995 Yasufuku 2001) Sensors with a

more simple structure can be prepared where

the polymer is deposited between two

conducting electrodes (Guadarrama et al

2000) Electrochemical polymerisation is

carried out using a three-electrode

electrochemical cell with the electrodes on

the substrate used as the working electrodes

(Gardner and Bartlett 1995) A potential is

applied across the electrode that initiates the

polymerisation of the polymer onto the

substrate The polymer is initially deposited

onto the electrodes and then grows between

them thus producing a complete thin film across

the electrode arrangement as the polymerisation

reactions progress Electrode thickness can

range from 1 to 10mm and the electrode gap

is typically 10-50mm (Albert and Lewis 2000

Guadarrama et al 2000) The total charge

applied during the polymerisation process

determines the thickness of the resultant film

while the final applied voltage determines the

doping concentration

Partridge et al (2000) described the sensor

characteristics of intrinsically conducting

polymers produced by pulsing the potential

during polymerisation and observed a

1-50 per cent relative differential resistance

change (DRRb) for saturated gas

The response of ICP sensors depends on

the sorption of the vapour into the sensing

material causing swelling and this affects

the electron density on the polymeric chains

(Albert and Lewis 2000) The sorption

properties of these materials essentially depend

on the diffusion rate of the permeant into the

polymer matrix as explained earlier for

composite conducting polymers Generally

the reported response times for ICPs vary

considerably from seconds to minutes eg 30 s

(Sotzing et al 2000) 60 s (Pearce et al

2003) and 180-240 s (Corcoran 1993a)

Polythiophene and poly(dodecylthiophene)

sensors have sensitivities from approximately

02 up to 18 (DRRb for 300 ppm gas for

10min) for gases such as CH4 CHCl3 and NH4

(Sakurai et al 2002) Polypyrrole gas sensors

were reported to have sensitivities (mVppm)

ranging from 026 to 501 depending on the

counter ions used in the polymers films

(Fang et al 2002) These response times and

sensitivities are reported for an extremely vast

variety of materials prepared by various

techniques sensor geometries and odour

molecules rendering direct comparisons

between sensors prepared by different

researchers difficult if not impractical

Intrinsically conducting polymers have a

number of advantages when used in e-nose

systems Increased discrimination when

developing sensor arrays can easily be achieved

with these materials as a wide range of

intrinsically conducting polymers are available

on the market (Albert and Lewis 2000) ICP

sensors operate at room temperature (Shurmer

and Gardner 1992) thereby simplifying the

required system electronics Conducting

polymers show a good response to a wide range

of analytes and have fast response and recovery

times especially for polar compounds

Problems related to intrinsically conducting

polymer sensors include poorly understood

signal transduction mechanisms difficulties in

Figure 5 Chemical structures of (a) polyaniline (b) polypyrrole and (c) polythiophene



Sensor Review


187

resolving some types of analytes high sensitivity

to humidity (Albert and Lewis 2000) and

the sensor response can drift with time

The fabrication techniques for these sensors

can also be difficult and time-consuming

(Nagle et al 1998) and large variations in the

properties of the sensors can occur from batch

to batch (Nagle et al 1998) Finally the

lifetime of these sensors can be quite short

typically 9-18 months due to oxidation of the

polymer (Schaller et al 1998)

Metal oxide sensors

The principle of operation of metal oxide

sensors is based on the change in conductance

of the oxide on interaction with a gas and

the change is usually proportional to the

concentration of the gas There are two types of

metal oxide sensors n-type (zinc oxide tin

dioxide titanium dioxide or iron (III) oxide)

which respond to reducing gases and p-type

(nickel oxide cobalt oxide) which respond to

oxidising gases (Pearce et al 2003) The n-type

sensor operates as follows oxygen in the air

reacts with the surface of the sensor and traps

any free electrons on the surface or at the grain

boundaries of the oxide grains This produces

large resistance in these areas due to the lack of

carriers and the resulting potential barriers

produced between the grains inhibit the carrier

mobility However if the sensor is introduced to

a reducing gas like H2 CH4 CO C2H5 or H2S

the resistance drops because the gas reacts

with the oxygen and releases an electron

This lowers the potential barrier and allows

the electrons to flow thereby increasing the

conductivity P-type sensors respond to

oxidising gases like O2 NO2 and Cl2 as these

gases remove electrons and produce holes

ie producing charge carriers Equations (1)

and (2) describe the reactions occurring at

the surface

1

2O2 thorn e2 O2ethsTHORN eth5THORN

RethgTHORN thornO2ethsTHORN ROethgTHORN thorn e eth6THORN

Where e is an electron from the oxide R(g) is

the reducing gas and g and s are the surface and

gas respectively (Albert and Lewis 2000

Pearce et al 2003)

Thick and thin film fabrication methods have

been used to produce metal oxide gas sensors

The metal oxide films are deposited using

screenprinting (Schmid et al 2003)

spincoating (Hamakawa et al 2002) RF

sputtering (Tao and Tsai 2002) or chemical

vapour deposition (Dai 1998) onto a flat or

tube type substrate made of alumina glass

silicon or some other ceramic Gold platinum

silver or aluminium electrodes are deposited

onto the substrate using the same methods

There are various electrode designs but the

interdigitated structure appears to be the most

common approach A heating element is printed

onto the back of the substrate to provide the

high temperatures required for metal oxides to

operate as gas sensors typically 200-5008C

Film thickness ranges from 10 to 300mm for

thick film and 6-1000 nm for thin film

(Schaller et al 1998) Catalytic metals are

sometimes applied on top of the oxides to

improve sensitivity to certain gases The same

preparative methods are used to apply the

catalytic metal (Albert and Lewis 2000

Penza et al 2001b c)

The sensitivity of oxide gas sensors

ethDR=RbTHORN=cethgasTHORN is calculated with DR frac14 R2 Rb

for oxidising gases and as DR frac14 Rb 2 R for

reducing gases where Rb is the baseline

resistance and R is the resistance on exposure to

the odour and c(gas) is the concentration of

the gas (Steffes et al 2001) The sensitivity of

the metal oxide sensor depends on the film

thickness and the temperature at which the

sensor is operated with thinner films being

more sensitive to gases (Schaller et al 1998)

The sensitivity can be improved by adding a

catalytic metal to the oxide however excessive

doping can reduce sensitivity The effect of

doping SnO2 sensors with Cu for example

demonstrated significant increases in sensitivity

(Galdikas et al 1995) The grain size of the

oxide also affects the sensitivity and selectivity to

particular gases as the grain boundaries act as

scattering centres for the electrons (Schaller

et al 1998) The ratio of the grain size (D) to

the electron depletion layer thickness (L)

ranging below D=2L frac14 1 ie the depletion

region extends over the entire grain governs the

sensitivity of the sensor (Behr and Fliegel

1995) Thin film metal oxide sensors saturate

quickly which can reduce the sensitivity range



Sensor Review


188

in which the sensor can operate The sensitivity

of metal oxide sensors is very dependent on the

operating temperature for example the

sensitivity DR=Rb (per 10 ppm NO2) for In2O3

gas sensors range from approximately 12 to 16

with the operating temperature varying from

350 to 4508C (Steffes et al 2001) For SnO2

gas sensors doped with Al2O3 the sensitivity per

500 ppm CH4 ranges from 02 to 07 between

250 and 4008C (Saha et al 2001)

The response times for tin oxides tend to be

very fast and can reach steady-state in less than

7 s (Doleman et al 1998a b) The general

response times for tin oxide sensors with gas

concentrations between 0 and 400 ppm and at

temperatures between 250 and 5008C are 5 to

35 s and the recovery times vary from 15 to 70 s

(Albert and Lewis 2000) Corcoran gave values

of 20 s for thick film metal oxide sensors and

12 s for thin filmmetal oxide sensors (Corcoran

1993b)

The main advantages of metal oxide sensors

are fast response and recovery times which

mainly depend on the temperature and the level

of interaction between the sensor and gas

(Penza et al 2001c) Thin film metal oxide

sensors are small and relatively inexpensive to

fabricate have lower power consumption than

thick film sensors and can be integrated directly

into the measurement circuitry (Dai 1998)

However they have many disadvantages due to

their high operating temperatures which results

in increased power consumption over sensors

fabricated from materials other than metal

oxides As a result no handheld e-nose system

has been fabricated utilising sensors prepared

from metal oxides (Pearce et al 2003)

They also suffer from sulphur poisoning due to

irreversible binding of compounds that contain

sulphur to the sensor oxide (Dickinson et al

1998) and ethanol can also blind the sensor

from other volatile organic compound (VOC)

gases (Schaller et al 1998)

Piezoelectric sensors used in e-nose arrays

There are two types of piezoelectric sensors

used in gas sensing the surface acoustic wave

(SAW) device and the quartz crystal

microbalance (QCM) The SAW device

produces a surface wave that travels along the

surface of the sensor while the QCM produces a

wave that travels through the bulk of the sensor

Both types of devices work on the principle that

a change in the mass of the piezoelectric sensor

coating due to gas absorption results in a change

in the resonant frequency on exposure to a

vapour (Albert and Lewis 2000)

Surface acoustic wave sensor

The SAW device is composed of a piezoelectric

substrate with an input (transmitting) and

output (receiving) interdigital transducer

deposited on top of the substrate

(Khlebarov et al 1992) The sensitive

membrane is placed between the transducers

Figure 6 and an ac signal is applied across the

input transducer creating an acoustic two-

dimensional wave that propagates along the

surface of the crystal at a depth of one

wavelength at operating frequencies between

100 and 400MHz (Pearce et al 2003) The

mass of the gas sensitive membrane of the SAW

device is changed on interaction with a

compatible analyte and causes the frequency of

the wave to be altered The change in frequency

with sorption of a vapour is given by

Df frac14 Df pcvKp=rp eth7THORN

where Dfp is the change in frequency caused

by the membrane cv is the vapour

concentration Kp is the partition coefficient

rp is the density of the polymer membrane

used (Albert and Lewis 2000 Nagle et al

1998 Pearce et al 2003)

The substrates are normally prepared from

ZnO lithium niobate or quartz which are

piezoelectric in nature (Pearce et al 2003)

The sensitive membrane is usually polymeric or

Figure 6 SAW sensor



Sensor Review


189

liquid crystal however phospholipids and fatty

acids deposited using Langmuir-Blodgett

techniques have also been used (Albert and

Lewis 2000) Generally SAW devices are

produced commercially by photolithography

where airbrush techniques are often used to

deposit the thin films (Nagle et al 1998

Schaller et al 1998) approximately 20-30 nm

thick (Groves and Zellers 2001) SAW devices

have also been produced by utilising screen

printing techniques (White and Turner 1997)

dip coating and spin coating

The sensitivity of the SAW device to a

particular odour depends on the type sensitive

membrane and the uptake of vapours by

polymers are governed by the same factors as

those for composite conducting polymer sensors

as detailed earlier in this paper The sensitivity is

normally quoted as differential response

ie Dfpppm of odour (Hierlemann et al 1995

Pearce et al 2003) Polymer-coated SAW

devices have quite low detection limits for

example tetrachloroethylene trichloroethylene

and methoxyflurane have been detected at

concentrations as low as 07 06 and 4ppm

respectively (Albert and Lewis 2000)

Groves et al used an array of SAW devices

with polymer coatings 20-30 nm thick to

detect 16 different solvents using four

different polymers Sensitivities ranging

from 05 up to 12Hzmgm3 have been achieved

with these devices (Groves et al 2001)

Organophosphorous compounds have also been

detected using these types of devices at

concentrations from 10 to 100 ppm at

temperatures between 25 and 508C where

a sensitivity of 27Hzppm at 308C

(Dejous et al 1995)

As can be seen above SAW devices can detect

a broad spectrum of odours due to the wide

range of gas sensitive coatings available

(Carey et al 1986 Grate and Abraham 1991)

and they also offer high sensitivity and fast

response times and their fabrication is

compatible with current planar IC technologies

(Nagle et al 1998)

However SAW devices suffer from poor

signal to noise performance because of the high

frequencies at which they operate (Schaller

et al 1998) and the circuitry required to

operate them is complex and expensive (Pearce

et al 2003) Batch to batch reproducibility is

difficult to achieve and the replacement of

damaged sensors was also found to be

problematic (Schaller et al 1998)

Quartz crystal microbalance sensor

Quartz crystal microbalance (QCM) gas

sensors operate on the same principle as SAW

devices When an ac voltage is applied across

the piezoelectric quartz crystal the material

oscillates at its resonant frequency normally

between 10 and 30MHz (Schaller et al 1998)

The three-dimensional wave produced

travels through the entire bulk of the crystal

A membrane is deposited onto the surface of

the crystal and this layer adsorbs gas when

exposed to the vapour which results in an

increase in its mass This increase in mass

alters the resonant frequency of the quartz

crystal and this change in resonant frequency is

therefore used for the detection of the vapour

(Albert and Lewis 2000)

The sensor shown in Figure 7 is composed

of a quartz disc coated with the absorbing

polymer layer and a set of gold electrodes

evaporated onto either side of the polymer

quartz structure Micromachining is used to

fabricate the QCM devices which makes the

fabrication of small sensor structures possible

Coatings can be between 10 nm and 1mm and

are applied using spincoating airbrushing

inkjet printing or dip coating (Schaller et al

1998)

The sensitivity of QCMs is given by

Df

Dcfrac14

eth223 pound 1026THORNf 2

Aeth8THORN

Figure 7 Quartz crystal microbalance with polymer coating



Sensor Review


190

where f is the fundamental frequency c is the

concentration and A is the area of the sensitive

film (Carey and Kowalski 1986) Higher

frequencies and smaller surface areas of

sensitive coatings give rise to higher sensitivity

(Carey 1987)

A quartz crystal microbalance gas sensor was

developed and had a linear frequency shift on

interaction with ethanol n-heptane and acetone

and showed a 16Hz shift for 25 ppm of ethanol

and 15Hz shift for 1 ppm of n-heptane

(Kim 2002) demonstrating their high

sensitivity to organic vapours QCM devices are

sensitive to a diverse range of analytes and are

also very selective (Pearce et al 2003)

Polyvinylpyrrolidone modified QCMs have

been used to detect various organic vapours and

had sensitivities in the range of 75-482Hzmgl

(Mirmohseni and Oladegaragoze 2003)

The advantages of using QCMs are fast

response times typically 10 s (Haug et al

1993) however response times of 30 s to 1min

have been reported (Carey 1987) However

QCM gas sensors have many disadvantages

which include complex fabrication processes

and interface circuitry (Nagle et al 1998) and

poor signal to noise performance due to surface

interferences and the size of the crystal (Nagle

et al 1998) As with SAW devices batch-to-

batch reproducibility of QCM gas sensors and

the replacement of damaged sensors are difficult

(Dickinson et al 1998)

Optical sensors used in e-nose arrays

Optical fibre sensor arrays are yet another

approach to odour identification in e-nose

systems The sides or tips of the optic fibres

(thickness 2mm) are coated with a fluorescent

dye encapsulated in a polymer matrix as shown

in Figure 8 Polarity alterations in the

fluorescent dye on interaction with the vapour

changes the dyersquos optical properties such as

intensity change spectrum change lifetime

change or wavelength shift in fluorescence

(Nagle et al 1998 Pearce et al 2003)

These optical changes are used as the response

mechanism for odour detection (Grattan and

Sun 2000 Gopel 1992)

The sensitivity depends on the type of

fluorescent dye or mixture of dyes and the

type of polymer used to support the dye

(Nagle et al 1998) The nature of the polymer

controls the response and the most important

factors are polarity hydrophobicity porosity

and swelling tendency (Nagle et al 1998

Pearce et al 2003) Adsorbants such as

alumina can be added to the polymer to

improve the response by lowering the detection

limits of the sensor (Walt et al 1998)

Polyanaline-coated optical sensors have been

used to detect ammonia at concentrations as

low as 1 ppm and the linear dynamic range

was between 180 and 18000 ppm ( Jin 2001)

Optical gas sensors have very fast response

times less than 10 s for sampling and analysis

(Walt et al 1998)

These compact lightweight optical gas

sensors can be multiplexed on a single fibre

network immune to electromagnetic

interference (EMI) and can operate in high

radiation areas due to Bragg and other grating

based optical sensors (Gopel 1992 Walt et al

1998)

However there are several disadvantages

of these types of sensors The associated

electronics and software are very complex

leading to increased cost and the sensors have

quite a short lifetime due to photobleaching

(Nagle et al 1998) However this problem

was overcome by measuring the temporal

Figure 8 A gas optical fibre sensor The odorant interacts with the material and causes a shift in the wavelength of the

propagating light wave



Sensor Review


191

responses because these remain consistent

despite photobleaching (Walt et al 1998)

Metal-oxide-semiconductor field-effect

transistor sensor and its use in the e-nose

The metal-oxide-semiconductor field-effect

transistor (MOSFET) is a transducer device

used in e-nose to transform a physicalchemical

change into an electrical signal The MOSFET

sensor is a metal-insulator-semiconductor

(MIS) device and its structure is shown in

Figure 9 (Eisele et al 2001)

This particular sensor works on the principle

that the threshold voltage of the MOSFET

sensor changes on interaction of the gate

material usually a catalytic metal with certain

gases such as hydrogen due to corresponding

changes in the work functions of the metal

and the oxide layers (Pearce et al 2003)

The changes in the work functions occur due to

the polarization of the surface and interface

of the catalytic metal and oxide layer when the

gas interacts with the catalytically active surface

(Kalman et al 2000) In order for the physical

changes in the sensor to occur the metal-

insulator interface has to be accessible to the

gas Therefore a porous gas sensitive gate

material is used to facilitate diffusion of gas into

the material (Eisele et al 2001) It has been

observed that the change in the threshold

voltage is proportional to the concentration of

the analyte and is used as the response

mechanism for the gas Changes in the drain-

source current and the gate voltage have also

been used as the response mechanisms for the

MOSFET gas sensors as they are also affected

by changes in the work function (Albert and

Lewis 2000 Nagle et al 1998)

Gas sensing MOSFETs are produced by

standard microfabrication techniques which

incorporate the deposition of gas sensitive

catalytic metals onto the silicon dioxide gate

layer (Nagle et al 1998) In the case of catalytic

metals such as platinum (Pt) palladium (Pd)

and iridium (Ir) the gate material is thermally

evaporated onto the gate oxide surface through

a mask forming 100-400 nm thick films or

3-30 nm thin films depending on the application

(Albert and Lewis 2000) Thick films have

been used to detect hydrogen and hydrogen

sulphide while thin films are more porous and

can detect amines alcohols and aldehydes

(Kalman et al 2000)

Polymers have also been used as the

gate material for MOSFET gas sensors

(Hatfield et al 2000) Covington et al 2001

used three polymers (poly(ethylene-co-vinyl

acetate poly(styrene-co-butadiene)

poly(9-vinylcarbazole)) mixed with 20 per cent

carbon black which were deposited onto the

FETs using a spray system The polymer

thickness was between 19 and 37mm

respectively (Covington et al 2001) These

MOSFETs which use polymers as the sensitive

membrane are more commonly called PolFETs

and can operate at room temperature

Apart from the standard MOSFET gas

sensor architecture a hybrid suspended gate

FET (HSGFET) gas sensor can also be

fabricated by micromachining (Figure 10)

The HSGFET is a metal air-gap insulator

(MAIS) device The air-gap allows easy access

to both the gate material and the insulator so

diffusion is not necessary and therefore a wider

choice of gas sensitive materials can be used

(Eisele et al 2001 Pearce et al 2003)

The catalytic metal thickness and the

operating temperatures of the MOSFETs in

Figure 10 Hybrid suspended gate field effect transistor

Figure 9 MOSFET gas sensor with gas sensitive membrane

deposited on top of SiO2



Sensor Review


192

Table

VC

hara

cter

istic

sof

com

mer

cial

e-no

ses

Man

ufacturer

Sensor

type

No

of

sensors

Applications

Pattern

recognition

commen

ts

Web

sitereferen

ceuniversity

backg

round

Airsense

analysisGmbH

MO

S10

Food

eval

uatio

nfla

vour

and

frag

ranc

ete

stin

gA

NN

D

C

PCA

Lapt

op

ww

wa

irsen

sec

om

AlphaMOS-Multi

Organ

olepticSystem

s

CP

MO

S

QC

M

SAW

6-24

Ana

lysi

sof

food

type

squ

ality

cont

rolo

ffoo

dst

orag

efr

esh

fish

and

petr

oche

mic

alpr

oduc

ts

pack

agin

gev

alua

tion

anal

ysis

of

dairy

prod

ucts

al

coho

licbe

vera

ges

and

perf

umes

AN

N

DFA

PCA

Des

ktop

ww

wa

lpha

-mos

com

Applied

Sensor

IR

MO

S

MO

SFET

QC

M

22Id

entifi

catio

nof

purit

ypr

oces

san

dqu

ality

cont

rol

envi

ronm

enta

lan

alys

is

med

ical

diag

nosi

s

AN

N

PCA

Lapt

op

ww

wa

pplie

dsen

sorc

om

Uni

vers

ityof

Link

opin

gs

Swed

en

AromaS

canPLC

CP

32En

viro

nmen

tal

mon

itorin

gch

emic

alqu

ality

cont

rol

phar

mac

eutic

alpr

oduc

tev

alua

tion

AN

N

Des

ktop

Uni

vers

ityof

Man

ches

ter

Inst

itute

ofsc

ienc

ean

dte

chno

logy

UK

Array

Tech

QC

M8

Dia

gnos

ing

lung

canc

er

food

anal

ysis

Uni

vers

ityof

Rom

e

Bloodhoundsensors

CP

14Fo

odev

alua

tion

flavo

uran

dfr

agra

nce

test

ing

mic

robi

olog

y

envi

ronm

enta

lm

onito

ring

degr

adat

ion

dete

ctio

n

AN

N

CA

PC

A

DA

Lapt

op

Uni

vers

ityof

Leed

sU

K

Cyran

oScience

Inc

CP

32Fo

odqu

ality

ch

emic

alan

alys

is

fres

hnes

ssp

oila

ge

cont

amin

atio

nde

tect

ion

cons

iste

ncy

info

ods

and

beve

rage

s

PCA

Palm

top

ww

wc

yran

osci

ence

sco

m

Cal

iforn

iain

stitu

teof

Tech

nolo

gy

USA

MarconiApplied

Technologies

QC

M

CP

MO

SSA

W

8-28

AN

N

DA

PC

AU

nive

rsity

ofW

arw

ick

UK

ElectronicSe

nsorTechnology

Inc

GC

SA

W1

Food

and

beve

rage

qual

ity

bact

eria

iden

tifica

tion

expl

osiv

es

and

drug

dete

ctio

nen

viro

nmen

tal

mon

itorin

g

SPR

Des

ktop

ww

we

stca

lcom

Forschungszen

trum

Karlsruhe

MO

SSA

W40

8

Envi

ronm

enta

lpr

otec

tion

indu

stria

lpr

oces

sco

ntro

lai

r

mon

itorin

gin

text

ilem

ills

fire

alar

ms

Qua

lity

cont

rol

info

od

prod

uctio

nA

utom

otiv

eap

plic

atio

ns

PCA

ww

wf

zkd

eFZ

K2

engl

ish

HKR-Sen

sorsystemeGmbH

QC

M6

Food

and

beve

rage

sco

smet

ics

and

perf

umes

or

gani

c

mat

eria

ls

phar

mac

eutic

alin

dust

ry

AN

N

CA

DFA

PC

A

Des

ktop

ww

wh

kr-s

enso

rde

Tech

nica

lU

nive

rsity

ofM

unic

h

Ger

man

y

Illumina

FOndash

Life

scie

nces

fo

odpr

oces

sing

ag

ricul

ture

ch

emic

alde

tect

ion

AN

Nw

ww

illu

min

aco

mTu

fts

Uni

vers

ity

USA

(Con

tinue

d)



Sensor Review


193

Table

V

Man

ufacturer

Sensor

type

No

of

sensors

Applications

Pattern

recognition

commen

ts

Web

sitereferen

ceuniversity

backg

round

Lennartz

ElectronicGmbH

MO

SQ

CM

16-4

0Fo

odan

dbe

vera

gepr

oces

sing

per

fum

eoi

lsa

gric

ultu

ralo

dour

s

and

chem

ical

anal

ysis

pr

oces

sco

ntro

l

AN

N

PCA

Des

ktop

ww

wle

nnar

tz-e

lect

roni

cde

PDF_

docu

men

ts

Uni

vers

ityof

Tubi

ngen

Marconitechnologies

MastiffElectronic

System

sLtd

CP

16Sn

iffs

palm

sfo

rpe

rson

alid

entifi

catio

nw

ww

mas

tiffc

ouk

MicrosensorSystem

sSA

W2

Che

mic

alag

ent

dete

ctio

nch

emic

alw

arfa

re(C

W)

agen

tsan

d

toxi

cin

dust

rial

chem

ical

s(T

ICs)

anal

ysis

Palm

top

ww

wm

icro

sens

orsy

stem

sco

mp

df

hazm

atca

d

OligoSe

nse

CO

ndashA

utom

otiv

eap

plic

atio

nsf

ood

eval

uatio

npa

ckag

ing

eval

uatio

nht

tp

ww

wo

ligos

ense

be

RST

Rostock

Rau

m-fah

rtund

UmweltschatzGmbH

MO

SQ

CM

SAW

6-10

Early

reco

gniti

onof

fires

w

arni

ngin

the

even

tof

esca

peof

haza

rdou

ssu

bsta

nces

le

akde

tect

ion

wor

kpla

cem

onito

ring

AN

N

PCA

Des

ktop

Ant

wer

pU

nive

rsity

B

elgi

um

ww

wr

st-r

osto

ckd

e

Shim

adzu

Co

MO

S6

PCA

D

eskt

op

Diag-Nose

Dia

gnos

ing

tube

rcul

osis

bo

wel

canc

ers

infe

ctio

nsin

wou

nds

and

the

urin

ary

trac

t

ww

wn

ose-

netw

ork

org

Cra

nfiel

dU

nive

rsity

B

edfo

rdsh

ire

Engl

and

Notes

MO

Sndash

met

alox

ide

sem

icon

duct

orC

Pndash

cond

uctin

gpo

lym

erQ

CM

ndashqu

artz

crys

talm

onito

rSA

Wndash

surf

ace

acou

stic

wav

eIR

ndashin

fra

red

MO

SFET

ndashm

etal

oxid

ese

mic

ondu

ctor

field

effe

ct

tran

sist

orG

Cndash

gas

chro

mat

ogra

phy

FOndash

fibre

optic

CO

ndashco

nduc

tive

olig

omer

AN

Nndash

artifi

cial

neur

alne

twor

kD

Cndash

dist

ance

clas

sifie

rsP

CA

ndashpr

inci

ple

com

pone

ntan

alys

isD

FAndash

disc

rimin

ant

func

tion

anal

ysis

C

Andash

clus

ter

anal

ysis

D

Andash

disc

rimin

ant

anal

ysis



Sensor Review


194

Table

VI

Sum

mar

yof

the

prop

ertie

sof

each

sens

orty

pere

view

ed

Sensortype

Mea

surand

Fabrication

Exam

plesofsensitivitydetection

rangedetectionlimits(DL)

Advantages

Disad

vantages

Referen

ce

Polymer

composites

Con

duct

ivity

Scre

enpr

intin

g

spin

coat

ing

dipc

oatin

g

spra

yco

atin

g

mic

rofa

bric

atio

n

ppb

for

HV

PGpp

mfo

rLV

PG

1pe

rce

ntD

RR

bp

pm

DL

01-

5pp

m

Ope

rate

atro

omte

mpe

ratu

re

chea

pdi

vers

era

nge

of

coat

ings

Sens

itive

tote

mpe

ratu

rean

d

hum

idity

Mun

ozet

al

(199

9)

Gar

dner

and

Dye

r(19

97)

and

Rya

net

al

(199

9)

Intrinsically

conducting

polymers

Con

duct

ivity

Elec

troc

hem

ical

chem

ical

poly

mer

isat

ion

01-

100

ppm

Sens

itive

topo

lar

anal

ytes

chea

pgo

odre

spon

setim

es

oper

ate

atro

omte

mpe

ratu

re

Sens

itive

tote

mpe

ratu

rean

d

hum

idity

su

ffer

from

base

line

drift

Nag

leet

al

(199

8)

Metal

oxides

Con

duct

ivity

Scre

enpr

intin

g

RF

sput

terin

gth

erm

al

evap

orat

ion

mic

rofa

bric

atio

n

5-50

0pp

mFa

stre

spon

sean

dre

cove

ry

times

ch

eap

Hig

hop

erat

ing

tem

pera

ture

s

suff

erfr

omsu

lphu

rpo

ison

ing

limite

dra

nge

ofco

atin

gs

Nag

leet

al

(199

8)

SAW

Piez

oele

ctric

ityPh

otol

ithog

raph

y

airb

rush

ing

scre

enpr

intin

g

dipc

oatin

gsp

inco

atin

g

1pg

to1

mg

ofva

pour

1pg

mas

s

chan

ge

DLfrac14

2pp

mfo

roc

tane

and

1pp

mN

O2

and

1pp

mH

2S

with

poly

mer

mem

bran

es

Div

erse

rang

eof

coat

ings

high

sens

itivi

ty

good

resp

onse

times

IC

inte

grat

able

Com

plex

inte

rfac

eci

rcui

try

diffi

cult

tore

prod

uce

Nag

leet

al

(199

8)

Alb

ert

and

Lew

in(2

000)

and

Penz

aet

al(

2001

a)

QCM

Piez

oele

ctric

ityM

icro

mac

hini

ng

spin

coat

ing

airb

rush

ing

inkj

etpr

intin

g

dipc

oatin

g

15

Hz

ppm

1

ngm

ass

chan

geD

iver

sera

nge

ofco

atin

gs

good

batc

hto

batc

h

repr

oduc

ibili

ty

Poor

sign

al-t

o-no

ise

ratio

com

plex

circ

uitr

y

Nag

leet

al

(199

8)an

d

Kim

and

Cho

i(2

002)

Optical

devices

Inte

nsity

spec

trum

Dip

coat

ing

Low

ppb

DL

(NH

3)frac14

1pp

mw

ith

poly

anili

neco

atin

g

Imm

une

toel

ectr

omag

netic

inte

rfer

ence

fa

stre

spon

se

times

ch

eap

light

wei

ght

Suff

erfr

omph

otob

leac

hing

com

plex

inte

rfac

eci

rcui

try

rest

ricte

dlig

htso

urce

s

Jin

etal

(2

001)

and

Nag

leet

al

(199

8)

MOSFET

Thre

shol

d

volta

ge

chan

ge

Mic

rofa

bric

atio

n

ther

mal

evap

orat

ion

28m

Vp

pmfo

rto

luen

e

DLfrac14

(am

ines

Su

lphi

des)frac14

01p

pm

Max

imum

resp

onse

frac1420

0m

V

espe

cial

lyfo

ram

ines

Smal

llo

wco

stse

nsor

sC

MO

S

inte

grat

ible

and

repr

oduc

ible

Bas

elin

edr

ift

need

cont

rolle

d

envi

ronm

ent

Cov

ingt

onet

al

(200

1)

and

Kal

man

etal

(20

00)

Notes

HV

PGndash

high

vapo

rpr

essu

rega

sLV

PGndash

low

vapo

rpr

essu

rega

sD

RR b

ndashre

lativ

edi

ffer

entia

lre

sist

ance

chan

ge



Sensor Review


195

the e-nose arrays are altered to provide different

selectivity patterns to different gases (Schaller

et al 1998) and operating temperatures are

usually between 50 and 1708C (Kalman et al

2000)

The factors that affect the sensitivity of

FET-based devices are operating temperature

composition and structure of the catalytic metal

(Lundstrom et al 1995 Schaller et al 1998)

The temperature is increased to decrease the

response and the recovery times (Dickinson

et al 1998) Typical sensitivities of ChemFET

sensors with carbon black-polymer composite

sensitive films was found to be approximately

28mVppm for toluene vapour (Covington

et al 2001) The detection limit of MOSFET

devices for amines and sulphides was 01 ppm

with Pt Ir and Pd gates and the maximum

response was approximately 200mV especially

for amines (Kalman et al 2000) Response time

varies from device to device and response times

from milliseconds up to 300 s have been

reported in the literature (Covington et al 2001

Eisele et al 2001 Wingbrant et al 2003)

MOSFET sensors have a number of

advantages and disadvantages when used in

e-nose arrays Gas sensing MOSFETs are

produced by microfabrication therefore

reproducibility is quite good and the sensor can

be incorporated into CMOS technology

resulting in small low cost sensors (Dickinson

et al 1998 Gu et al 1998 Nagle et al 1998

Pearce et al 2003 Schaller et al 1998 )

The sensors can suffer from baseline drift and

instability depending on the sensing material

used (Nagle et al 1998) If CMOS is used the

electronic components of the chip have to be

sealed because the sensor needs a gas inlet so it

can penetrate the gate (Nagle et al 1998)

The gas flows across the sensor and also the

operating temperature have serious effects on

the sensitivity and selectivity of the sensor so

control of the surrounding environment is

important (Eklov et al 1997 Nagle et al

1998) This does not suit a handheld e-nose

Commercial e-nose systems

Manufacturers of commercial e-nose systems

have become plentiful in recent times and

produce a wide range of products utilising

different sensor types depending mainly on the

applications Many of these systems are

reviewed in Table V

Conclusions

Conducting polymer composite intrinsically

conducting polymer and metal oxide

conductivity gas sensors SAWand QCM

piezoelectric gas sensors optical gas sensors and

MOSFET gas sensors have been reviewed in this

paper These systems offer excellent

discrimination and lead the way for a new

generation of ldquosmart sensorsrdquo which will mould

the future commercial markets for gas sensors

The principle of operation fabrication

techniques advantages disadvantages and

applications of each sensor type in e-nose

systems have been clearly outlined and a

summary of this information is given inTable VI

References

Albert KJ and Lewis NS (2000) ldquoCross reactive chemicalsensor arraysrdquo Chem Rev Vol 100 pp 2595-626

Behr G and Fliegel W (1995) ldquoElectrical properties andimprovement of the gas sensitivity in multiple-dopedsno2rdquo Sensors and Actuators B Chemical Vol 26Nos 1-3 pp 33-7

Briglin SM Freund MS Tokumaru P and Lewis NS(2002) ldquoExploitation of spatiotemporal informationand geometric optimization of signalnoiseperformance using arrays of carbon black-polymercomposite vapor detectorsrdquo Sensors and Actuators BChemical Vol 82 No 1 pp 54-74

Carey PW and Kowalski BR (1986) ldquoChemicalpiezoelectric sensor and sensor array characterisationrdquoAnalytical chemistry Vol 58 pp 3077-84

Carey PW Beebe KR and Kowalski BR (1986)ldquoSelection of adsorbates for chemical sensor arrays bypattern recognitionrdquo Analytical chemistry Vol 58pp 149-53

Carey PW Beebe KR and Kowalski BR (1987)ldquoMulticomponent analysis using an array ofpiezoelectric crystal sensorsrdquo Analytical chemistryVol 59 pp 1529-34

Charlesworth JM Partridge AC and Garrard N (1997)ldquoMechanistic studies on the interactions betweenpoly(pyrrole) and orgaic vaporsrdquo J Phys ChemVol 97 pp 5418-23

Chen JH Iwata H Tsubokawa N Maekawa Y andYoshida M (2002) ldquoNovel vapor sensor from polymer-grafted carbon black effects of heat-treatment andgamma-ray radiation-treatment on the response of



Sensor Review


196

sensor material in cyclohexane vaporrdquo PolymerVol 43 No 8 pp 2201-6

Comyn J (1985) Polymer permeability Elsevier AppliedScience Amsterdam

Corcoran P (1993) ldquoElectronic odor sensing systemsrdquoElectronics and Communication Engineering JournalVol 5 No 5 pp 303-8

Covington JA Gardner JW Briand D and de Rooij NF(2001) ldquoA polymer gate fet sensor array for detectingorganic vapoursrdquo Sensors and Actuators B ChemicalVol 77 Nos 1-2 pp 155-62

Dai G (1998) ldquoA study of the sensing properties of thin filmsensor to trimethylaminerdquo Sensors and Actuators BChemical Vol 53 Nos 1-2 pp 8-12

Dejous C Rebiere D Pistre J Tiret C and Planade R(1995) ldquoA surface acoustic wave gas sensor detectionof organophosphorus compoundsrdquo Sensors andActuators B Chemical Vol 24 Nos 1-3 pp 58-61

Dickinson TA White J Kauer JS and Walt DR (1998)ldquoCurrent trends in lsquoartificial-nosersquo technologyrdquo Trendsin Biotechnology Vol 16 No 6 pp 250-8

Doleman BJ Lonergan MC Severin EJ Vaid TP andLewis NS (1998a) ldquoQuantitative study of theresolving power of arrays of carbon black-polymercomposites in various vapor-sensing tasksrdquo AnalyticalChemistry Vol 70 No 19 pp 4177-90

Doleman BJ Sanner RD Severin EJ Grubbs RH andLewis NS (1998b) ldquoUse of compatible polymerblends to fabricate arrays of carbon black-polymercomposite vapor detectorsrdquo Analytical chemistry Vol70 pp 2560-4

Eisele I Doll T and Burgmair M (2001) ldquoLow power gasdetection with fet sensorsrdquo Sensors and Actuators BChemical Vol 78 No 1-3 pp 19-25

Eklov T Sundgren H and Lundstrom I (1997) ldquoDistributedchemical sensingrdquo Sensors and Actuators B ChemicalVol 45 No 1 pp 71-7

Fang Q Chetwynd DG Covington JA Toh C-S andGardner JW (2002) ldquoMicro-gas-sensor withconducting polymersrdquo Sensors and Actuators BChemical Vol 84 No 1 pp 66-71

Fraden J (1996) Aip Handbook of Modern Sensors AIPNew York

Freund MS and Lewis NS (1995) ldquoA chemically diverseconducting polymer based electronic noserdquo Proc NatlAcad Sci USA Vol 92 pp 2652-6

Galdikas A Mironas A and Setkus A (1995) ldquoCopper-doping level effect on sensitivity and selectivity of tinoxide thin-film gas sensorrdquo Sensors and Actuators BChemical Vol 26 No 1-3 pp 29-32

Gardner JW and Bartlett PN (1995) ldquoApplication ofconducting polymer technology in microsystemsrdquoSensors and Actuators A Physical Vol 51 No 1pp 57-66

Gardner JW and Dyer DC (1997) ldquoHigh-precisionintelligent interface for a hybrid electronic noserdquoSensors and Actuators A Physical Vol 62 No 1-3pp 724-8

George SC and Thomas S (2001) ldquoTransport phenomenathrough polymeric systemsrdquo Progress in PolymerScience Vol 26 No 6 pp 985-1017

Gopel W Hesse J and Zemel JN (Eds) (1989) MagneticSensors VCH Weinheim

Gopel W Hesse J and Zemel JN (Eds) (1992) OpticalSensors VCH Weinheim

Grate WJ and Abraham MH (1991) ldquoSolubilityinteractions and design of chemically selective sorbantcoatings for chemical sensors and arraysrdquo Sensors andActuators B Vol 3 pp 85-111

Grattan KTV and Sun T (2000) ldquoFiber optic sensortechnology an overviewrdquo Sensors and Actuators APhysical Vol 82 Nos 1-3 pp 40-61

Groves WA and Zellers ET (2001) ldquoAnalysis of solventvapors in breath and ambient air with a surfaceacoustic wave sensor arrayrdquo The Annals ofOccupational Hygiene Vol 45 No 8 pp 609-23

Gu C Sun L Zhang T Li T and Zhang X (1998) ldquoHigh-sensitivity phthalocyanine lb film gas sensor based onfield effect transistorsrdquo Thin Solid Films Vol 327-329pp 383-6

Guadarrama A Fernandez JA Iniguez M Souto J andde Saja JA (2000) ldquoArray of conducting polymersensors for the characterisation of winesrdquo AnalyticaChimica Acta Vol 411 No 1-2 pp 193-200

Hamakawa S Li L Li A and Iglesia E (2002) ldquoSynthesisand hydrogen permeation properties of membranesbased on dense srce095yb005o3-[alpha] thin filmsrdquoSolid State Ionics Vol 148 No 1-2 pp 71-81

Harsanyi G (2000) ldquoPolymer films in sensor applicationsa review of present uses and future possibilitiesrdquoSensor Review Vol 20 No 2 pp 98-105

Hatfield JV Covington JA and Gardner JW (2000)ldquoGasfets incorporating conducting polymers as gatematerialsrdquo Sensors and Actuators B ChemicalVol 65 No 1-3 pp 253-6

Haug M Schierbaum KD Gauglitz G and Gopel W(1993) ldquoChemical sensors based upon polysiloxanesComparison between optical quartz microbalancecalorimetric and capacitance sensorsrdquo Sensors andActuators B Chemical Vol 11 No 1-3 pp 383-91

Heeger AJ (2001) ldquoSemiconducting and metallic polymersthe fourth generation of polymeric materialsrdquo CurrentApplied Physics Vol 1 pp 247-67

Hierlemann A Weimar U Kraus G Schweizer-BerberichM and Gopel W (1995) ldquoPolymer-based sensorarrays and multicomponent analysis for the detectionof hazardous organic vapours in the environmentrdquoSensors and Actuators B Chemical Vol 26 Nos 1-3pp 126-34

Jin Z Su Y and Duan Y (2001) ldquoDevelopment of apolyaniline-based optical ammonia sensorrdquo Sensorsand Actuators B Chemical Vol 72 No 1 pp 75-9

Johnson DJ (1997) Process control instrumentationtechnology Prentice-Hall

Kalman E-L Lofvendahl A Winquist F and Lundstrom I(2000) ldquoClassification of complex gas mixtures fromautomotive leather using an electronic noserdquoAnalytica Chimica Acta Vol 403 No 1-2 pp 31-8

Khlebarov ZP Stoyanova AI and Topalova DI (1992)ldquoSurface acoustic wave gas sensorsrdquo Sensors andActuators B Chemical Vol 8 No 1 pp 33-40



Sensor Review


197

Kim YH and Choi KJ (2002) ldquoFabrication and applicationof an activated carbon coated quartz crystal sensorrdquoSensors and Actuators B Vol 87 pp 196-200

Lonergan MC Severin EJ Doleman BJ Beaber SAGrubb RH and Lewis NS (1996) ldquoArray-based vaporsensing using chemically sensitive carbon black-polymer resistorsrdquo Chemistry of Materials Vol 8 No9 pp 2298-312

Lundstrom I Ederth T Kariis H Sundgren H Spetz Aand Winquist F (1995) ldquoRecent developments infield-effect gas sensorsrdquo Sensors and Actuators BChemical Vol 23 No 2-3 pp 127-33

Matthews B Jing L Sunshine S Lerner L and Judy JW(2002) ldquoEffects of electrode configuration on polymercarbon-black composite chemical vapor sensorperformancerdquo IEEE Sensors Journal Vol 2 No 3pp 160-8

Mirmohseni A and Oladegaragoze A (2003) ldquoConstructionof a sensor for determination of ammonia and aliphaticamines using polyvinylpyrrolidone coated quartz crystalmicrobalancerdquo Sensors and Actuators B ChemicalVol 89 No 1-2 pp 164-72

Munoz BC Steinthal G and Sunshine S (1999)ldquoConductive polymer-carbon black composites-basedsensor arrays for use in an electronic noserdquo SensorReview Vol 19 No 4 pp 300-5

Nagle HT Gutierrez-Osuna R and Schiffman SS (1998)ldquoThe how and why of electronic hosesrdquo IEEESpectrum Vol 35 No 9 pp 22-31

Partridge AC Jansen ML and Arnold WM (2000)ldquoConducting polymer-based sensorsrdquo MaterialsScience and Engineering C Vol 12 No 1-2 pp 37-42

Pearce TC Schiffman SS Nagle HT and Gardner JW(2003) Handbook of Machine Olfaction Wiley-VCHWeinheim

Penza M Cassano G Sergi A Lo Sterzo C and RussoMV (2001a) ldquoSaw chemical sensing using poly-ynesand organometallic polymer filmsrdquo Sensors andActuators B Chemical Vol 81 No 1 pp 88-98

Penza M Cassano G and Tortorella F (2001b) ldquoGasrecognition by activated wo3 thin-film sensors arrayrdquoSensors and Actuators B Chemical Vol 81 No 1pp 115-21

Penza M Cassano G Tortorella F and Zaccaria G(2001c) ldquoClassification of food beverages andperfumes by wo3 thin-film sensors array and patternrecognition techniquesrdquo Sensors and Actuators BChemical Vol 73 No 1 pp 76-87

Ryan MA Buehler MG Homer ML Mannatt KSLau B Jackson S and Zhou H (1999) The SecondInternational Conference on Integrated MicroNanotechnology for Space Applications-EnablingTechnologies for New Space Systems Pasadena CAUSA

Saha M Banerjee A Halder AK Mondal J Sen A andMaiti HS (2001) ldquoEffect of alumina addition onmethane sensitivity of tin dioxide thick filmsrdquo Sensorsand Actuators B Chemical Vol 79 No 2-3 pp 192-5

Sakurai Y Jung H-S Shimanouchi T Inoguchi T MoritaS Kuboi R and Natsukawa K (2002) ldquoNovel array-type gas sensors using conducting polymers and theirperformance for gas identificationrdquo Sensors andActuators B Chemical Vol 83 No 1-3 pp 270-5

Schaller E Bosset JO and Escher F (1998) ldquoElectronicnoses and their application to foodrdquo Lebensmittel-Wissenschaft und-Technologie Vol 31 No 4pp 305-16

Schmid W Barsan N and Weimar U (2003) ldquoSensing ofhydrocarbons with tin oxide sensors possible reactionpath as revealed by consumption measurementsrdquoSensors and Actuators B Chemical Vol 89 No 3pp 232-6

Severin EJ Doleman BJ and Lewis NS (2000) ldquoAninvestigation of the concentration dependence andresponse to analyte mixtures of carbon blackinsulatingorganic polymer composite vapor detectorsrdquoAnalytical chemistry Vol 72 pp 658-68

Severin EJ Sanner RD Doleman BJ and Lewis NS(1998) ldquoDifferential detection of enantiomericgaseous analytes using carbon black-chiral polymercomposite chemically sensitive resistorsrdquo Analyticalchemistry Vol 70 pp 1440-3

Shurmer HV and Gardner JW (1992) ldquoOdourdiscrimination with an electronic noserdquo Sensors andActuators B Vol 8 pp 1-11

Sotzing GA Phend JN and Lewis NS (2000) ldquoHighlysensitive detective and discrimination of biogenicamines ulitizing arrays of polyanalinecarbon blackcomposite vapor detectorsrdquo Chem Mater Vol 12pp 593-5

Steffes H Imawan C Solzbacher F and Obermeier E(2001) ldquoEnhancement of no2 sensing properties ofin2o3-based thin films using an au or ti surfacemodificationrdquo Sensors and Actuators B ChemicalVol 78 No 1-3 pp 106-12

Tao W-H and Tsai C-H (2002) ldquoH2s sensing properties ofnoble metal doped wo3 thin film sensor fabricated bymicromachiningrdquo Sensors and Actuators B ChemicalVol 81 No 2-3 pp 237-47

Vieth WR (1991) Diffusion in and Through PolymersPrinciples and Applications Hanser Publishers Munich

Walt DR Dickinson T White J Kauer J Johnson SEngelhardt H Sutter J and Jurs P (1998) ldquoOpticalsensor arrays for odor recognitionrdquo Biosensors andBioelectronics Vol 13 No 6 pp 697-9

White NM and Turner JD (1997) ldquoThick-film sensors pastpresent and futurerdquo Meas Sci Technology Vol 8pp 1-20

Wingbrant H Lundstrom I and Lloyd Spetz A (2003) ldquoThespeed of response of MISiCFET devicesrdquo Sensors andActuators B Chemical Vol 93 Nos 1-3 pp 286-94

Yasufuku (2001) ldquoElectroconductive polymers and theirapplications in Japanrdquo IEEE Electrical InsulationMagazine Vol 17 Nos 5 pp 14-24

Zee F and Judy JW (2001) ldquoMicromachined polymer-basedchemical gas sensor arrayrdquo Sensors and Actuators BChemical Vol 72 No 2 pp 120-8



Sensor Review


198

(Pearce et al 2003) The odour sample is

drawn across the sensor array and induces a

reversible physical andor chemical change in

the sensing material which causes an associated

change in electrical properties such as

conductivity (Harsanyi 2000) Each ldquocellrdquo in

the array can behave like a receptor by

responding to different odours to varying

degrees (Shurmer and Gardner 1992) These

changes are transduced into electrical signals

which are preprocessed and conditioned before

identification by a pattern recognition system as

shown in Figure 1 The e-nose system is

designed so that the overall response pattern

from the array is unique for a given odour in a

family of odours to be considered by the system

E-nose sensor response to odorants

The response of e-nose sensors to odorants is

generally regarded as a first order time response

The first stage in odour analysis is to flush a

reference gas through the sensor to obtain a

baseline The sensor is exposed to the odorant

which causes changes in its output signal until

the sensor reaches steady-state The odorant is

finally flushed out of the sensor using the

reference gas and the sensor returns back to its

baseline as shown in Figure 2 The time during

which the sensor is exposed to the odorant is

referred to as the response time while the time

it takes the sensor to return to its baseline

resistance is called the recovery time

The next stage in analysing the odour is

sensor response manipulation with respect to

the baseline This process compensates for

noise drift and also for inherently large or

small signals (Pearce et al 2003) The three

most commonly used methods as defined by

Pearce et al (2003) are as follows

(1) Differential the baseline xs(0) is subtracted

from the sensor response xs(t) to remove

any noise or drift dA present The baseline

manipulated response ys(t) is determined

by

ysethtTHORN frac14 ethxsethtTHORN thorn dATHORN2 ethxseth0THORN thorn dATHORN

frac14 xsethtTHORN2 xseth0THORN eth1THORN

(2) Relative the sensor response is divided by

the baseline This process eliminates

multiplicative drift dM and a dimensionless

response ys(t) is obtained

ysethtTHORN frac14xsethtTHORNeth1thorn dMTHORN

xseth0THORNeth1thorn dMTHORNfrac14

xsethtTHORN


(3) Fractional the baseline is subtracted from

the response xs(t) and then divided by the

baseline xs(0) from the sensor response

which provides a dimensionless normalised

Figure 1 Comparison of the mammalian olfactory system and the e-nose system



Sensor Review


182













paper











S frac14Dy

Dxeth4THORN
























































Sensor Review


183


































Table II






















Lewis 1995)










before exposure
















Table IV










Sensor Review


184




























Thomas 2001)




































Substrate

Electrode

material

Electrode

dimensions

(mm)

Electrode gap

(mm)

Electrode

thickness

(nm) Reference








Sensor Review


185

















































































et al 1997) and













composites



60 Partridge (2000)

180-240 Corcoran (1993b)




Sensor Review


186
















































2003) and 180-240 s (Corcoran 1993a)



































Sensor Review


187












Metal oxide sensors





























the surface

1






Pearce et al 2003)























































Sensor Review


188










250 and 4008C (Saha et al 2001)











1993b)

































































Figure 6 SAW sensor



Sensor Review


189






































(Dejous et al 1995)








(Nagle et al 1998)





































1998)


Df

Dcfrac14


Aeth8THORN




Sensor Review


190






(Carey 1987)



























































(Walt et al 1998)







1998)












Sensor Review


191




















































(Kalman et al 2000)































Sensor Review


192

Table

VC

hara

cter

istic

sof

com

mer

cial

e-no

ses

Man

ufacturer

Sensor

type

No

of

sensors

Applications

Pattern

recognition

commen

ts

Web

sitereferen

ceuniversity

backg

round

Airsense

analysisGmbH

MO

S10

Food

eval

uatio

nfla

vour

and

frag

ranc

ete

stin

gA

NN

D

C

PCA

Lapt

op

ww

wa

irsen

sec

om

AlphaMOS-Multi

Organ

olepticSystem

s

CP

MO

S

QC

M

SAW

6-24

Ana

lysi

sof

food

type

squ

ality

cont

rolo

ffoo

dst

orag

efr

esh

fish

and

petr

oche

mic

alpr

oduc

ts

pack

agin

gev

alua

tion

anal

ysis

of

dairy

prod

ucts

al

coho

licbe

vera

ges

and

perf

umes

AN

N

DFA

PCA

Des

ktop

ww

wa

lpha

-mos

com

Applied

Sensor

IR

MO

S

MO

SFET

QC

M

22Id

entifi

catio

nof

purit

ypr

oces

san

dqu

ality

cont

rol

envi

ronm

enta

lan

alys

is

med

ical

diag

nosi

s

AN

N

PCA

Lapt

op

ww

wa

pplie

dsen

sorc

om

Uni

vers

ityof

Link

opin

gs

Swed

en

AromaS

canPLC

CP

32En

viro

nmen

tal

mon

itorin

gch

emic

alqu

ality

cont

rol

phar

mac

eutic

alpr

oduc

tev

alua

tion

AN

N

Des

ktop

Uni

vers

ityof

Man

ches

ter

Inst

itute

ofsc

ienc

ean

dte

chno

logy

UK

Array

Tech

QC

M8

Dia

gnos

ing

lung

canc

er

food

anal

ysis

Uni

vers

ityof

Rom

e

Bloodhoundsensors

CP

14Fo

odev

alua

tion

flavo

uran

dfr

agra

nce

test

ing

mic

robi

olog

y

envi

ronm

enta

lm

onito

ring

degr

adat

ion

dete

ctio

n

AN

N

CA

PC

A

DA

Lapt

op

Uni

vers

ityof

Leed

sU

K

Cyran

oScience

Inc

CP

32Fo

odqu

ality

ch

emic

alan

alys

is

fres

hnes

ssp

oila

ge

cont

amin

atio

nde

tect

ion

cons

iste

ncy

info

ods

and

beve

rage

s

PCA

Palm

top

ww

wc

yran

osci

ence

sco

m

Cal

iforn

iain

stitu

teof

Tech

nolo

gy

USA

MarconiApplied

Technologies

QC

M

CP

MO

SSA

W

8-28

AN

N

DA

PC

AU

nive

rsity

ofW

arw

ick

UK

ElectronicSe

nsorTechnology

Inc

GC

SA

W1

Food

and

beve

rage

qual

ity

bact

eria

iden

tifica

tion

expl

osiv

es

and

drug

dete

ctio

nen

viro

nmen

tal

mon

itorin

g

SPR

Des

ktop

ww

we

stca

lcom

Forschungszen

trum

Karlsruhe

MO

SSA

W40

8

Envi

ronm

enta

lpr

otec

tion

indu

stria

lpr

oces

sco

ntro

lai

r

mon

itorin

gin

text

ilem

ills

fire

alar

ms

Qua

lity

cont

rol

info

od

prod

uctio

nA

utom

otiv

eap

plic

atio

ns

PCA

ww

wf

zkd

eFZ

K2

engl

ish

HKR-Sen

sorsystemeGmbH

QC

M6

Food

and

beve

rage

sco

smet

ics

and

perf

umes

or

gani

c

mat

eria

ls

phar

mac

eutic

alin

dust

ry

AN

N

CA

DFA

PC

A

Des

ktop

ww

wh

kr-s

enso

rde

Tech

nica

lU

nive

rsity

ofM

unic

h

Ger

man

y

Illumina

FOndash

Life

scie

nces

fo

odpr

oces

sing

ag

ricul

ture

ch

emic

alde

tect

ion

AN

Nw

ww

illu

min

aco

mTu

fts

Uni

vers

ity

USA

(Con

tinue

d)



Sensor Review


193

Table

V

Man

ufacturer

Sensor

type

No

of

sensors

Applications

Pattern

recognition

commen

ts

Web

sitereferen

ceuniversity

backg

round

Lennartz

ElectronicGmbH

MO

SQ

CM

16-4

0Fo

odan

dbe

vera

gepr

oces

sing

per

fum

eoi

lsa

gric

ultu

ralo

dour

s

and

chem

ical

anal

ysis

pr

oces

sco

ntro

l

AN

N

PCA

Des

ktop

ww

wle

nnar

tz-e

lect

roni

cde

PDF_

docu

men

ts

Uni

vers

ityof

Tubi

ngen

Marconitechnologies

MastiffElectronic

System

sLtd

CP

16Sn

iffs

palm

sfo

rpe

rson

alid

entifi

catio

nw

ww

mas

tiffc

ouk

MicrosensorSystem

sSA

W2

Che

mic

alag

ent

dete

ctio

nch

emic

alw

arfa

re(C

W)

agen

tsan

d

toxi

cin

dust

rial

chem

ical

s(T

ICs)

anal

ysis

Palm

top

ww

wm

icro

sens

orsy

stem

sco

mp

df

hazm

atca

d

OligoSe

nse

CO

ndashA

utom

otiv

eap

plic

atio

nsf

ood

eval

uatio

npa

ckag

ing

eval

uatio

nht

tp

ww

wo

ligos

ense

be

RST

Rostock

Rau

m-fah

rtund

UmweltschatzGmbH

MO

SQ

CM

SAW

6-10

Early

reco

gniti

onof

fires

w

arni

ngin

the

even

tof

esca

peof

haza

rdou

ssu

bsta

nces

le

akde

tect

ion

wor

kpla

cem

onito

ring

AN

N

PCA

Des

ktop

Ant

wer

pU

nive

rsity

B

elgi

um

ww

wr

st-r

osto

ckd

e

Shim

adzu

Co

MO

S6

PCA

D

eskt

op

Diag-Nose

Dia

gnos

ing

tube

rcul

osis

bo

wel

canc

ers

infe

ctio

nsin

wou

nds

and

the

urin

ary

trac

t

ww

wn

ose-

netw

ork

org

Cra

nfiel

dU

nive

rsity

B

edfo

rdsh

ire

Engl

and

Notes

MO

Sndash

met

alox

ide

sem

icon

duct

orC

Pndash

cond

uctin

gpo

lym

erQ

CM

ndashqu

artz

crys

talm

onito

rSA

Wndash

surf

ace

acou

stic

wav

eIR

ndashin

fra

red

MO

SFET

ndashm

etal

oxid

ese

mic

ondu

ctor

field

effe

ct

tran

sist

orG

Cndash

gas

chro

mat

ogra

phy

FOndash

fibre

optic

CO

ndashco

nduc

tive

olig

omer

AN

Nndash

artifi

cial

neur

alne

twor

kD

Cndash

dist

ance

clas

sifie

rsP

CA

ndashpr

inci

ple

com

pone

ntan

alys

isD

FAndash

disc

rimin

ant

func

tion

anal

ysis

C

Andash

clus

ter

anal

ysis

D

Andash

disc

rimin

ant

anal

ysis



Sensor Review


194

Table

VI

Sum

mar

yof

the

prop

ertie

sof

each

sens

orty

pere

view

ed

Sensortype

Mea

surand

Fabrication

Exam



Advantages

Disad

vantages

Referen

ce

Polymer

composites

Con

duct

ivity

Scre

enpr

intin

g

spin

coat

ing

dipc

oatin

g

spra

yco

atin

g

mic

rofa

bric

atio

n

ppb

for

HV

PGpp

mfo

rLV

PG

1pe

rce

ntD

RR

bp

pm

DL

01-

5pp

m

Ope

rate

atro

omte

mpe

ratu

re

chea

pdi

vers

era

nge

of

coat

ings

Sens

itive

tote

mpe

ratu

rean

d

hum

idity

Mun

ozet

al

(199

9)

Gar

dner

and

Dye

r(19

97)

and

Rya

net

al

(199

9)

Intrinsically

conducting

polymers

Con

duct

ivity

Elec

troc

hem

ical

chem

ical

poly

mer

isat

ion

01-

100

ppm

Sens

itive

topo

lar

anal

ytes

chea

pgo

odre

spon

setim

es

oper

ate

atro

omte

mpe

ratu

re

Sens

itive

tote

mpe

ratu

rean

d

hum

idity

su

ffer

from

base

line

drift

Nag

leet

al

(199

8)

Metal

oxides

Con

duct

ivity

Scre

enpr

intin

g

RF

sput

terin

gth

erm

al

evap

orat

ion

mic

rofa

bric

atio

n

5-50

0pp

mFa

stre

spon

sean

dre

cove

ry

times

ch

eap

Hig

hop

erat

ing

tem

pera

ture

s

suff

erfr

omsu

lphu

rpo

ison

ing

limite

dra

nge

ofco

atin

gs

Nag

leet

al

(199

8)

SAW

Piez

oele

ctric

ityPh

otol

ithog

raph

y

airb

rush

ing

scre

enpr

intin

g

dipc

oatin

gsp

inco

atin

g

1pg

to1

mg

ofva

pour

1pg

mas

s

chan

ge

DLfrac14

2pp

mfo

roc

tane

and

1pp

mN

O2

and

1pp

mH

2S

with

poly

mer

mem

bran

es

Div

erse

rang

eof

coat

ings

high

sens

itivi

ty

good

resp

onse

times

IC

inte

grat

able

Com

plex

inte

rfac

eci

rcui

try

diffi

cult

tore

prod

uce

Nag

leet

al

(199

8)

Alb

ert

and

Lew

in(2

000)

and

Penz

aet

al(

2001

a)

QCM

Piez

oele

ctric

ityM

icro

mac

hini

ng

spin

coat

ing

airb

rush

ing

inkj

etpr

intin

g

dipc

oatin

g

15

Hz

ppm

1

ngm

ass

chan

geD

iver

sera

nge

ofco

atin

gs

good

batc

hto

batc

h

repr

oduc

ibili

ty

Poor

sign

al-t

o-no

ise

ratio

com

plex

circ

uitr

y

Nag

leet

al

(199

8)an

d

Kim

and

Cho

i(2

002)

Optical

devices

Inte

nsity

spec

trum

Dip

coat

ing

Low

ppb

DL

(NH

3)frac14

1pp

mw

ith

poly

anili

neco

atin

g

Imm

une

toel

ectr

omag

netic

inte

rfer

ence

fa

stre

spon

se

times

ch

eap

light

wei

ght

Suff

erfr

omph

otob

leac

hing

com

plex

inte

rfac

eci

rcui

try

rest

ricte

dlig

htso

urce

s

Jin

etal

(2

001)

and

Nag

leet

al

(199

8)

MOSFET

Thre

shol

d

volta

ge

chan

ge

Mic

rofa

bric

atio

n

ther

mal

evap

orat

ion

28m

Vp

pmfo

rto

luen

e

DLfrac14

(am

ines

Su

lphi

des)frac14

01p

pm

Max

imum

resp

onse

frac1420

0m

V

espe

cial

lyfo

ram

ines

Smal

llo

wco

stse

nsor

sC

MO

S

inte

grat

ible

and

repr

oduc

ible

Bas

elin

edr

ift

need

cont

rolle

d

envi

ronm

ent

Cov

ingt

onet

al

(200

1)

and

Kal

man

etal

(20

00)

Notes

HV

PGndash

high

vapo

rpr

essu

rega

sLV

PGndash

low

vapo

rpr

essu

rega

sD

RR b

ndashre

lativ

edi

ffer

entia

lre

sist

ance

chan

ge



Sensor Review


195





2000)















































reviewed in Table V

Conclusions















References











Sensor Review


196






































Sensor Review


197
































Sensor Review


198













paper











S frac14Dy

Dxeth4THORN
























































Sensor Review


183


































Table II






















Lewis 1995)










before exposure
















Table IV










Sensor Review


184




























Thomas 2001)




































Substrate

Electrode

material

Electrode

dimensions

(mm)

Electrode gap

(mm)

Electrode

thickness

(nm) Reference








Sensor Review


185

















































































et al 1997) and













composites



60 Partridge (2000)

180-240 Corcoran (1993b)




Sensor Review


186
















































2003) and 180-240 s (Corcoran 1993a)



































Sensor Review


187












Metal oxide sensors





























the surface

1






Pearce et al 2003)























































Sensor Review


188










250 and 4008C (Saha et al 2001)











1993b)

































































Figure 6 SAW sensor



Sensor Review


189






































(Dejous et al 1995)








(Nagle et al 1998)





































1998)


Df

Dcfrac14


Aeth8THORN




Sensor Review


190






(Carey 1987)



























































(Walt et al 1998)







1998)












Sensor Review


191




















































(Kalman et al 2000)































Sensor Review


192

Table

VC

hara

cter

istic

sof

com

mer

cial

e-no

ses

Man

ufacturer

Sensor

type

No

of

sensors

Applications

Pattern

recognition

commen

ts

Web

sitereferen

ceuniversity

backg

round

Airsense

analysisGmbH

MO

S10

Food

eval

uatio

nfla

vour

and

frag

ranc

ete

stin

gA

NN

D

C

PCA

Lapt

op

ww

wa

irsen

sec

om

AlphaMOS-Multi

Organ

olepticSystem

s

CP

MO

S

QC

M

SAW

6-24

Ana

lysi

sof

food

type

squ

ality

cont

rolo

ffoo

dst

orag

efr

esh

fish

and

petr

oche

mic

alpr

oduc

ts

pack

agin

gev

alua

tion

anal

ysis

of

dairy

prod

ucts

al

coho

licbe

vera

ges

and

perf

umes

AN

N

DFA

PCA

Des

ktop

ww

wa

lpha

-mos

com

Applied

Sensor

IR

MO

S

MO

SFET

QC

M

22Id

entifi

catio

nof

purit

ypr

oces

san

dqu

ality

cont

rol

envi

ronm

enta

lan

alys

is

med

ical

diag

nosi

s

AN

N

PCA

Lapt

op

ww

wa

pplie

dsen

sorc

om

Uni

vers

ityof

Link

opin

gs

Swed

en

AromaS

canPLC

CP

32En

viro

nmen

tal

mon

itorin

gch

emic

alqu

ality

cont

rol

phar

mac

eutic

alpr

oduc

tev

alua

tion

AN

N

Des

ktop

Uni

vers

ityof

Man

ches

ter

Inst

itute

ofsc

ienc

ean

dte

chno

logy

UK

Array

Tech

QC

M8

Dia

gnos

ing

lung

canc

er

food

anal

ysis

Uni

vers

ityof

Rom

e

Bloodhoundsensors

CP

14Fo

odev

alua

tion

flavo

uran

dfr

agra

nce

test

ing

mic

robi

olog

y

envi

ronm

enta

lm

onito

ring

degr

adat

ion

dete

ctio

n

AN

N

CA

PC

A

DA

Lapt

op

Uni

vers

ityof

Leed

sU

K

Cyran

oScience

Inc

CP

32Fo

odqu

ality

ch

emic

alan

alys

is

fres

hnes

ssp

oila

ge

cont

amin

atio

nde

tect

ion

cons

iste

ncy

info

ods

and

beve

rage

s

PCA

Palm

top

ww

wc

yran

osci

ence

sco

m

Cal

iforn

iain

stitu

teof

Tech

nolo

gy

USA

MarconiApplied

Technologies

QC

M

CP

MO

SSA

W

8-28

AN

N

DA

PC

AU

nive

rsity

ofW

arw

ick

UK

ElectronicSe

nsorTechnology

Inc

GC

SA

W1

Food

and

beve

rage

qual

ity

bact

eria

iden

tifica

tion

expl

osiv

es

and

drug

dete

ctio

nen

viro

nmen

tal

mon

itorin

g

SPR

Des

ktop

ww

we

stca

lcom

Forschungszen

trum

Karlsruhe

MO

SSA

W40

8

Envi

ronm

enta

lpr

otec

tion

indu

stria

lpr

oces

sco

ntro

lai

r

mon

itorin

gin

text

ilem

ills

fire

alar

ms

Qua

lity

cont

rol

info

od

prod

uctio

nA

utom

otiv

eap

plic

atio

ns

PCA

ww

wf

zkd

eFZ

K2

engl

ish

HKR-Sen

sorsystemeGmbH

QC

M6

Food

and

beve

rage

sco

smet

ics

and

perf

umes

or

gani

c

mat

eria

ls

phar

mac

eutic

alin

dust

ry

AN

N

CA

DFA

PC

A

Des

ktop

ww

wh

kr-s

enso

rde

Tech

nica

lU

nive

rsity

ofM

unic

h

Ger

man

y

Illumina

FOndash

Life

scie

nces

fo

odpr

oces

sing

ag

ricul

ture

ch

emic

alde

tect

ion

AN

Nw

ww

illu

min

aco

mTu

fts

Uni

vers

ity

USA

(Con

tinue

d)



Sensor Review


193

Table

V

Man

ufacturer

Sensor

type

No

of

sensors

Applications

Pattern

recognition

commen

ts

Web

sitereferen

ceuniversity

backg

round

Lennartz

ElectronicGmbH

MO

SQ

CM

16-4

0Fo

odan

dbe

vera

gepr

oces

sing

per

fum

eoi

lsa

gric

ultu

ralo

dour

s

and

chem

ical

anal

ysis

pr

oces

sco

ntro

l

AN

N

PCA

Des

ktop

ww

wle

nnar

tz-e

lect

roni

cde

PDF_

docu

men

ts

Uni

vers

ityof

Tubi

ngen

Marconitechnologies

MastiffElectronic

System

sLtd

CP

16Sn

iffs

palm

sfo

rpe

rson

alid

entifi

catio

nw

ww

mas

tiffc

ouk

MicrosensorSystem

sSA

W2

Che

mic

alag

ent

dete

ctio

nch

emic

alw

arfa

re(C

W)

agen

tsan

d

toxi

cin

dust

rial

chem

ical

s(T

ICs)

anal

ysis

Palm

top

ww

wm

icro

sens

orsy

stem

sco

mp

df

hazm

atca

d

OligoSe

nse

CO

ndashA

utom

otiv

eap

plic

atio

nsf

ood

eval

uatio

npa

ckag

ing

eval

uatio

nht

tp

ww

wo

ligos

ense

be

RST

Rostock

Rau

m-fah

rtund

UmweltschatzGmbH

MO

SQ

CM

SAW

6-10

Early

reco

gniti

onof

fires

w

arni

ngin

the

even

tof

esca

peof

haza

rdou

ssu

bsta

nces

le

akde

tect

ion

wor

kpla

cem

onito

ring

AN

N

PCA

Des

ktop

Ant

wer

pU

nive

rsity

B

elgi

um

ww

wr

st-r

osto

ckd

e

Shim

adzu

Co

MO

S6

PCA

D

eskt

op

Diag-Nose

Dia

gnos

ing

tube

rcul

osis

bo

wel

canc

ers

infe

ctio

nsin

wou

nds

and

the

urin

ary

trac

t

ww

wn

ose-

netw

ork

org

Cra

nfiel

dU

nive

rsity

B

edfo

rdsh

ire

Engl

and

Notes

MO

Sndash

met

alox

ide

sem

icon

duct

orC

Pndash

cond

uctin

gpo

lym

erQ

CM

ndashqu

artz

crys

talm

onito

rSA

Wndash

surf

ace

acou

stic

wav

eIR

ndashin

fra

red

MO

SFET

ndashm

etal

oxid

ese

mic

ondu

ctor

field

effe

ct

tran

sist

orG

Cndash

gas

chro

mat

ogra

phy

FOndash

fibre

optic

CO

ndashco

nduc

tive

olig

omer

AN

Nndash

artifi

cial

neur

alne

twor

kD

Cndash

dist

ance

clas

sifie

rsP

CA

ndashpr

inci

ple

com

pone

ntan

alys

isD

FAndash

disc

rimin

ant

func

tion

anal

ysis

C

Andash

clus

ter

anal

ysis

D

Andash

disc

rimin

ant

anal

ysis



Sensor Review


194

Table

VI

Sum

mar

yof

the

prop

ertie

sof

each

sens

orty

pere

view

ed

Sensortype

Mea

surand

Fabrication

Exam



Advantages

Disad

vantages

Referen

ce

Polymer

composites

Con

duct

ivity

Scre

enpr

intin

g

spin

coat

ing

dipc

oatin

g

spra

yco

atin

g

mic

rofa

bric

atio

n

ppb

for

HV

PGpp

mfo

rLV

PG

1pe

rce

ntD

RR

bp

pm

DL

01-

5pp

m

Ope

rate

atro

omte

mpe

ratu

re

chea

pdi

vers

era

nge

of

coat

ings

Sens

itive

tote

mpe

ratu

rean

d

hum

idity

Mun

ozet

al

(199

9)

Gar

dner

and

Dye

r(19

97)

and

Rya

net

al

(199

9)

Intrinsically

conducting

polymers

Con

duct

ivity

Elec

troc

hem

ical

chem

ical

poly

mer

isat

ion

01-

100

ppm

Sens

itive

topo

lar

anal

ytes

chea

pgo

odre

spon

setim

es

oper

ate

atro

omte

mpe

ratu

re

Sens

itive

tote

mpe

ratu

rean

d

hum

idity

su

ffer

from

base

line

drift

Nag

leet

al

(199

8)

Metal

oxides

Con

duct

ivity

Scre

enpr

intin

g

RF

sput

terin

gth

erm

al

evap

orat

ion

mic

rofa

bric

atio

n

5-50

0pp

mFa

stre

spon

sean

dre

cove

ry

times

ch

eap

Hig

hop

erat

ing

tem

pera

ture

s

suff

erfr

omsu

lphu

rpo

ison

ing

limite

dra

nge

ofco

atin

gs

Nag

leet

al

(199

8)

SAW

Piez

oele

ctric

ityPh

otol

ithog

raph

y

airb

rush

ing

scre

enpr

intin

g

dipc

oatin

gsp

inco

atin

g

1pg

to1

mg

ofva

pour

1pg

mas

s

chan

ge

DLfrac14

2pp

mfo

roc

tane

and

1pp

mN

O2

and

1pp

mH

2S

with

poly

mer

mem

bran

es

Div

erse

rang

eof

coat

ings

high

sens

itivi

ty

good

resp

onse

times

IC

inte

grat

able

Com

plex

inte

rfac

eci

rcui

try

diffi

cult

tore

prod

uce

Nag

leet

al

(199

8)

Alb

ert

and

Lew

in(2

000)

and

Penz

aet

al(

2001

a)

QCM

Piez

oele

ctric

ityM

icro

mac

hini

ng

spin

coat

ing

airb

rush

ing

inkj

etpr

intin

g

dipc

oatin

g

15

Hz

ppm

1

ngm

ass

chan

geD

iver

sera

nge

ofco

atin

gs

good

batc

hto

batc

h

repr

oduc

ibili

ty

Poor

sign

al-t

o-no

ise

ratio

com

plex

circ

uitr

y

Nag

leet

al

(199

8)an

d

Kim

and

Cho

i(2

002)

Optical

devices

Inte

nsity

spec

trum

Dip

coat

ing

Low

ppb

DL

(NH

3)frac14

1pp

mw

ith

poly

anili

neco

atin

g

Imm

une

toel

ectr

omag

netic

inte

rfer

ence

fa

stre

spon

se

times

ch

eap

light

wei

ght

Suff

erfr

omph

otob

leac

hing

com

plex

inte

rfac

eci

rcui

try

rest

ricte

dlig

htso

urce

s

Jin

etal

(2

001)

and

Nag

leet

al

(199

8)

MOSFET

Thre

shol

d

volta

ge

chan

ge

Mic

rofa

bric

atio

n

ther

mal

evap

orat

ion

28m

Vp

pmfo

rto

luen

e

DLfrac14

(am

ines

Su

lphi

des)frac14

01p

pm

Max

imum

resp

onse

frac1420

0m

V

espe

cial

lyfo

ram

ines

Smal

llo

wco

stse

nsor

sC

MO

S

inte

grat

ible

and

repr

oduc

ible

Bas

elin

edr

ift

need

cont

rolle

d

envi

ronm

ent

Cov

ingt

onet

al

(200

1)

and

Kal

man

etal

(20

00)

Notes

HV

PGndash

high

vapo

rpr

essu

rega

sLV

PGndash

low

vapo

rpr

essu

rega

sD

RR b

ndashre

lativ

edi

ffer

entia

lre

sist

ance

chan

ge



Sensor Review


195





2000)















































reviewed in Table V

Conclusions















References











Sensor Review


196






































Sensor Review


197
































Sensor Review


198


































Table II






















Lewis 1995)










before exposure
















Table IV










Sensor Review


184




























Thomas 2001)




































Substrate

Electrode

material

Electrode

dimensions

(mm)

Electrode gap

(mm)

Electrode

thickness

(nm) Reference








Sensor Review


185

















































































et al 1997) and













composites



60 Partridge (2000)

180-240 Corcoran (1993b)




Sensor Review


186
















































2003) and 180-240 s (Corcoran 1993a)



































Sensor Review


187












Metal oxide sensors





























the surface

1






Pearce et al 2003)























































Sensor Review


188










250 and 4008C (Saha et al 2001)











1993b)

































































Figure 6 SAW sensor



Sensor Review


189






































(Dejous et al 1995)








(Nagle et al 1998)





































1998)


Df

Dcfrac14


Aeth8THORN




Sensor Review


190






(Carey 1987)



























































(Walt et al 1998)







1998)












Sensor Review


191




















































(Kalman et al 2000)































Sensor Review


192

Table

VC

hara

cter

istic

sof

com

mer

cial

e-no

ses

Man

ufacturer

Sensor

type

No

of

sensors

Applications

Pattern

recognition

commen

ts

Web

sitereferen

ceuniversity

backg

round

Airsense

analysisGmbH

MO

S10

Food

eval

uatio

nfla

vour

and

frag

ranc

ete

stin

gA

NN

D

C

PCA

Lapt

op

ww

wa

irsen

sec

om

AlphaMOS-Multi

Organ

olepticSystem

s

CP

MO

S

QC

M

SAW

6-24

Ana

lysi

sof

food

type

squ

ality

cont

rolo

ffoo

dst

orag

efr

esh

fish

and

petr

oche

mic

alpr

oduc

ts

pack

agin

gev

alua

tion

anal

ysis

of

dairy

prod

ucts

al

coho

licbe

vera

ges

and

perf

umes

AN

N

DFA

PCA

Des

ktop

ww

wa

lpha

-mos

com

Applied

Sensor

IR

MO

S

MO

SFET

QC

M

22Id

entifi

catio

nof

purit

ypr

oces

san

dqu

ality

cont

rol

envi

ronm

enta

lan

alys

is

med

ical

diag

nosi

s

AN

N

PCA

Lapt

op

ww

wa

pplie

dsen

sorc

om

Uni

vers

ityof

Link

opin

gs

Swed

en

AromaS

canPLC

CP

32En

viro

nmen

tal

mon

itorin

gch

emic

alqu

ality

cont

rol

phar

mac

eutic

alpr

oduc

tev

alua

tion

AN

N

Des

ktop

Uni

vers

ityof

Man

ches

ter

Inst

itute

ofsc

ienc

ean

dte

chno

logy

UK

Array

Tech

QC

M8

Dia

gnos

ing

lung

canc

er

food

anal

ysis

Uni

vers

ityof

Rom

e

Bloodhoundsensors

CP

14Fo

odev

alua

tion

flavo

uran

dfr

agra

nce

test

ing

mic

robi

olog

y

envi

ronm

enta

lm

onito

ring

degr

adat

ion

dete

ctio

n

AN

N

CA

PC

A

DA

Lapt

op

Uni

vers

ityof

Leed

sU

K

Cyran

oScience

Inc

CP

32Fo

odqu

ality

ch

emic

alan

alys

is

fres

hnes

ssp

oila

ge

cont

amin

atio

nde

tect

ion

cons

iste

ncy

info

ods

and

beve

rage

s

PCA

Palm

top

ww

wc

yran

osci

ence

sco

m

Cal

iforn

iain

stitu

teof

Tech

nolo

gy

USA

MarconiApplied

Technologies

QC

M

CP

MO

SSA

W

8-28

AN

N

DA

PC

AU

nive

rsity

ofW

arw

ick

UK

ElectronicSe

nsorTechnology

Inc

GC

SA

W1

Food

and

beve

rage

qual

ity

bact

eria

iden

tifica

tion

expl

osiv

es

and

drug

dete

ctio

nen

viro

nmen

tal

mon

itorin

g

SPR

Des

ktop

ww

we

stca

lcom

Forschungszen

trum

Karlsruhe

MO

SSA

W40

8

Envi

ronm

enta

lpr

otec

tion

indu

stria

lpr

oces

sco

ntro

lai

r

mon

itorin

gin

text

ilem

ills

fire

alar

ms

Qua

lity

cont

rol

info

od

prod

uctio

nA

utom

otiv

eap

plic

atio

ns

PCA

ww

wf

zkd

eFZ

K2

engl

ish

HKR-Sen

sorsystemeGmbH

QC

M6

Food

and

beve

rage

sco

smet

ics

and

perf

umes

or

gani

c

mat

eria

ls

phar

mac

eutic

alin

dust

ry

AN

N

CA

DFA

PC

A

Des

ktop

ww

wh

kr-s

enso

rde

Tech

nica

lU

nive

rsity

ofM

unic

h

Ger

man

y

Illumina

FOndash

Life

scie

nces

fo

odpr

oces

sing

ag

ricul

ture

ch

emic

alde

tect

ion

AN

Nw

ww

illu

min

aco

mTu

fts

Uni

vers

ity

USA

(Con

tinue

d)



Sensor Review


193

Table

V

Man

ufacturer

Sensor

type

No

of

sensors

Applications

Pattern

recognition

commen

ts

Web

sitereferen

ceuniversity

backg

round

Lennartz

ElectronicGmbH

MO

SQ

CM

16-4

0Fo

odan

dbe

vera

gepr

oces

sing

per

fum

eoi

lsa

gric

ultu

ralo

dour

s

and

chem

ical

anal

ysis

pr

oces

sco

ntro

l

AN

N

PCA

Des

ktop

ww

wle

nnar

tz-e

lect

roni

cde

PDF_

docu

men

ts

Uni

vers

ityof

Tubi

ngen

Marconitechnologies

MastiffElectronic

System

sLtd

CP

16Sn

iffs

palm

sfo

rpe

rson

alid

entifi

catio

nw

ww

mas

tiffc

ouk

MicrosensorSystem

sSA

W2

Che

mic

alag

ent

dete

ctio

nch

emic

alw

arfa

re(C

W)

agen

tsan

d

toxi

cin

dust

rial

chem

ical

s(T

ICs)

anal

ysis

Palm

top

ww

wm

icro

sens

orsy

stem

sco

mp

df

hazm

atca

d

OligoSe

nse

CO

ndashA

utom

otiv

eap

plic

atio

nsf

ood

eval

uatio

npa

ckag

ing

eval

uatio

nht

tp

ww

wo

ligos

ense

be

RST

Rostock

Rau

m-fah

rtund

UmweltschatzGmbH

MO

SQ

CM

SAW

6-10

Early

reco

gniti

onof

fires

w

arni

ngin

the

even

tof

esca

peof

haza

rdou

ssu

bsta

nces

le

akde

tect

ion

wor

kpla

cem

onito

ring

AN

N

PCA

Des

ktop

Ant

wer

pU

nive

rsity

B

elgi

um

ww

wr

st-r

osto

ckd

e

Shim

adzu

Co

MO

S6

PCA

D

eskt

op

Diag-Nose

Dia

gnos

ing

tube

rcul

osis

bo

wel

canc

ers

infe

ctio

nsin

wou

nds

and

the

urin

ary

trac

t

ww

wn

ose-

netw

ork

org

Cra

nfiel

dU

nive

rsity

B

edfo

rdsh

ire

Engl

and

Notes

MO

Sndash

met

alox

ide

sem

icon

duct

orC

Pndash

cond

uctin

gpo

lym

erQ

CM

ndashqu

artz

crys

talm

onito

rSA

Wndash

surf

ace

acou

stic

wav

eIR

ndashin

fra

red

MO

SFET

ndashm

etal

oxid

ese

mic

ondu

ctor

field

effe

ct

tran

sist

orG

Cndash

gas

chro

mat

ogra

phy

FOndash

fibre

optic

CO

ndashco

nduc

tive

olig

omer

AN

Nndash

artifi

cial

neur

alne

twor

kD

Cndash

dist

ance

clas

sifie

rsP

CA

ndashpr

inci

ple

com

pone

ntan

alys

isD

FAndash

disc

rimin

ant

func

tion

anal

ysis

C

Andash

clus

ter

anal

ysis

D

Andash

disc

rimin

ant

anal

ysis



Sensor Review


194

Table

VI

Sum

mar

yof

the

prop

ertie

sof

each

sens

orty

pere

view

ed

Sensortype

Mea

surand

Fabrication

Exam



Advantages

Disad

vantages

Referen

ce

Polymer

composites

Con

duct

ivity

Scre

enpr

intin

g

spin

coat

ing

dipc

oatin

g

spra

yco

atin

g

mic

rofa

bric

atio

n

ppb

for

HV

PGpp

mfo

rLV

PG

1pe

rce

ntD

RR

bp

pm

DL

01-

5pp

m

Ope

rate

atro

omte

mpe

ratu

re

chea

pdi

vers

era

nge

of

coat

ings

Sens

itive

tote

mpe

ratu

rean

d

hum

idity

Mun

ozet

al

(199

9)

Gar

dner

and

Dye

r(19

97)

and

Rya

net

al

(199

9)

Intrinsically

conducting

polymers

Con

duct

ivity

Elec

troc

hem

ical

chem

ical

poly

mer

isat

ion

01-

100

ppm

Sens

itive

topo

lar

anal

ytes

chea

pgo

odre

spon

setim

es

oper

ate

atro

omte

mpe

ratu

re

Sens

itive

tote

mpe

ratu

rean

d

hum

idity

su

ffer

from

base

line

drift

Nag

leet

al

(199

8)

Metal

oxides

Con

duct

ivity

Scre

enpr

intin

g

RF

sput

terin

gth

erm

al

evap

orat

ion

mic

rofa

bric

atio

n

5-50

0pp

mFa

stre

spon

sean

dre

cove

ry

times

ch

eap

Hig

hop

erat

ing

tem

pera

ture

s

suff

erfr

omsu

lphu

rpo

ison

ing

limite

dra

nge

ofco

atin

gs

Nag

leet

al

(199

8)

SAW

Piez

oele

ctric

ityPh

otol

ithog

raph

y

airb

rush

ing

scre

enpr

intin

g

dipc

oatin

gsp

inco

atin

g

1pg

to1

mg

ofva

pour

1pg

mas

s

chan

ge

DLfrac14

2pp

mfo

roc

tane

and

1pp

mN

O2

and

1pp

mH

2S

with

poly

mer

mem

bran

es

Div

erse

rang

eof

coat

ings

high

sens

itivi

ty

good

resp

onse

times

IC

inte

grat

able

Com

plex

inte

rfac

eci

rcui

try

diffi

cult

tore

prod

uce

Nag

leet

al

(199

8)

Alb

ert

and

Lew

in(2

000)

and

Penz

aet

al(

2001

a)

QCM

Piez

oele

ctric

ityM

icro

mac

hini

ng

spin

coat

ing

airb

rush

ing

inkj

etpr

intin

g

dipc

oatin

g

15

Hz

ppm

1

ngm

ass

chan

geD

iver

sera

nge

ofco

atin

gs

good

batc

hto

batc

h

repr

oduc

ibili

ty

Poor

sign

al-t

o-no

ise

ratio

com

plex

circ

uitr

y

Nag

leet

al

(199

8)an

d

Kim

and

Cho

i(2

002)

Optical

devices

Inte

nsity

spec

trum

Dip

coat

ing

Low

ppb

DL

(NH

3)frac14

1pp

mw

ith

poly

anili

neco

atin

g

Imm

une

toel

ectr

omag

netic

inte

rfer

ence

fa

stre

spon

se

times

ch

eap

light

wei

ght

Suff

erfr

omph

otob

leac

hing

com

plex

inte

rfac

eci

rcui

try

rest

ricte

dlig

htso

urce

s

Jin

etal

(2

001)

and

Nag

leet

al

(199

8)

MOSFET

Thre

shol

d

volta

ge

chan

ge

Mic

rofa

bric

atio

n

ther

mal

evap

orat

ion

28m

Vp

pmfo

rto

luen

e

DLfrac14

(am

ines

Su

lphi

des)frac14

01p

pm

Max

imum

resp

onse

frac1420

0m

V

espe

cial

lyfo

ram

ines

Smal

llo

wco

stse

nsor

sC

MO

S

inte

grat

ible

and

repr

oduc

ible

Bas

elin

edr

ift

need

cont

rolle

d

envi

ronm

ent

Cov

ingt

onet

al

(200

1)

and

Kal

man

etal

(20

00)

Notes

HV

PGndash

high

vapo

rpr

essu

rega

sLV

PGndash

low

vapo

rpr

essu

rega

sD

RR b

ndashre

lativ

edi

ffer

entia

lre

sist

ance

chan

ge



Sensor Review


195





2000)















































reviewed in Table V

Conclusions















References











Sensor Review


196






































Sensor Review


197
































Sensor Review


198




























Thomas 2001)




































Substrate

Electrode

material

Electrode

dimensions

(mm)

Electrode gap

(mm)

Electrode

thickness

(nm) Reference








Sensor Review


185

















































































et al 1997) and













composites



60 Partridge (2000)

180-240 Corcoran (1993b)




Sensor Review


186
















































2003) and 180-240 s (Corcoran 1993a)



































Sensor Review


187












Metal oxide sensors





























the surface

1






Pearce et al 2003)























































Sensor Review


188










250 and 4008C (Saha et al 2001)











1993b)

































































Figure 6 SAW sensor



Sensor Review


189






































(Dejous et al 1995)








(Nagle et al 1998)





































1998)


Df

Dcfrac14


Aeth8THORN




Sensor Review


190






(Carey 1987)



























































(Walt et al 1998)







1998)












Sensor Review


191




















































(Kalman et al 2000)































Sensor Review


192

Table

VC

hara

cter

istic

sof

com

mer

cial

e-no

ses

Man

ufacturer

Sensor

type

No

of

sensors

Applications

Pattern

recognition

commen

ts

Web

sitereferen

ceuniversity

backg

round

Airsense

analysisGmbH

MO

S10

Food

eval

uatio

nfla

vour

and

frag

ranc

ete

stin

gA

NN

D

C

PCA

Lapt

op

ww

wa

irsen

sec

om

AlphaMOS-Multi

Organ

olepticSystem

s

CP

MO

S

QC

M

SAW

6-24

Ana

lysi

sof

food

type

squ

ality

cont

rolo

ffoo

dst

orag

efr

esh

fish

and

petr

oche

mic

alpr

oduc

ts

pack

agin

gev

alua

tion

anal

ysis

of

dairy

prod

ucts

al

coho

licbe

vera

ges

and

perf

umes

AN

N

DFA

PCA

Des

ktop

ww

wa

lpha

-mos

com

Applied

Sensor

IR

MO

S

MO

SFET

QC

M

22Id

entifi

catio

nof

purit

ypr

oces

san

dqu

ality

cont

rol

envi

ronm

enta

lan

alys

is

med

ical

diag

nosi

s

AN

N

PCA

Lapt

op

ww

wa

pplie

dsen

sorc

om

Uni

vers

ityof

Link

opin

gs

Swed

en

AromaS

canPLC

CP

32En

viro

nmen

tal

mon

itorin

gch

emic

alqu

ality

cont

rol

phar

mac

eutic

alpr

oduc

tev

alua

tion

AN

N

Des

ktop

Uni

vers

ityof

Man

ches

ter

Inst

itute

ofsc

ienc

ean

dte

chno

logy

UK

Array

Tech

QC

M8

Dia

gnos

ing

lung

canc

er

food

anal

ysis

Uni

vers

ityof

Rom

e

Bloodhoundsensors

CP

14Fo

odev

alua

tion

flavo

uran

dfr

agra

nce

test

ing

mic

robi

olog

y

envi

ronm

enta

lm

onito

ring

degr

adat

ion

dete

ctio

n

AN

N

CA

PC

A

DA

Lapt

op

Uni

vers

ityof

Leed

sU

K

Cyran

oScience

Inc

CP

32Fo

odqu

ality

ch

emic

alan

alys

is

fres

hnes

ssp

oila

ge

cont

amin

atio

nde

tect

ion

cons

iste

ncy

info

ods

and

beve

rage

s

PCA

Palm

top

ww

wc

yran

osci

ence

sco

m

Cal

iforn

iain

stitu

teof

Tech

nolo

gy

USA

MarconiApplied

Technologies

QC

M

CP

MO

SSA

W

8-28

AN

N

DA

PC

AU

nive

rsity

ofW

arw

ick

UK

ElectronicSe

nsorTechnology

Inc

GC

SA

W1

Food

and

beve

rage

qual

ity

bact

eria

iden

tifica

tion

expl

osiv

es

and

drug

dete

ctio

nen

viro

nmen

tal

mon

itorin

g

SPR

Des

ktop

ww

we

stca

lcom

Forschungszen

trum

Karlsruhe

MO

SSA

W40

8

Envi

ronm

enta

lpr

otec

tion

indu

stria

lpr

oces

sco

ntro

lai

r

mon

itorin

gin

text

ilem

ills

fire

alar

ms

Qua

lity

cont

rol

info

od

prod

uctio

nA

utom

otiv

eap

plic

atio

ns

PCA

ww

wf

zkd

eFZ

K2

engl

ish

HKR-Sen

sorsystemeGmbH

QC

M6

Food

and

beve

rage

sco

smet

ics

and

perf

umes

or

gani

c

mat

eria

ls

phar

mac

eutic

alin

dust

ry

AN

N

CA

DFA

PC

A

Des

ktop

ww

wh

kr-s

enso

rde

Tech

nica

lU

nive

rsity

ofM

unic

h

Ger

man

y

Illumina

FOndash

Life

scie

nces

fo

odpr

oces

sing

ag

ricul

ture

ch

emic

alde

tect

ion

AN

Nw

ww

illu

min

aco

mTu

fts

Uni

vers

ity

USA

(Con

tinue

d)



Sensor Review


193

Table

V

Man

ufacturer

Sensor

type

No

of

sensors

Applications

Pattern

recognition

commen

ts

Web

sitereferen

ceuniversity

backg

round

Lennartz

ElectronicGmbH

MO

SQ

CM

16-4

0Fo

odan

dbe

vera

gepr

oces

sing

per

fum

eoi

lsa

gric

ultu

ralo

dour

s

and

chem

ical

anal

ysis

pr

oces

sco

ntro

l

AN

N

PCA

Des

ktop

ww

wle

nnar

tz-e

lect

roni

cde

PDF_

docu

men

ts

Uni

vers

ityof

Tubi

ngen

Marconitechnologies

MastiffElectronic

System

sLtd

CP

16Sn

iffs

palm

sfo

rpe

rson

alid

entifi

catio

nw

ww

mas

tiffc

ouk

MicrosensorSystem

sSA

W2

Che

mic

alag

ent

dete

ctio

nch

emic

alw

arfa

re(C

W)

agen

tsan

d

toxi

cin

dust

rial

chem

ical

s(T

ICs)

anal

ysis

Palm

top

ww

wm

icro

sens

orsy

stem

sco

mp

df

hazm

atca

d

OligoSe

nse

CO

ndashA

utom

otiv

eap

plic

atio

nsf

ood

eval

uatio

npa

ckag

ing

eval

uatio

nht

tp

ww

wo

ligos

ense

be

RST

Rostock

Rau

m-fah

rtund

UmweltschatzGmbH

MO

SQ

CM

SAW

6-10

Early

reco

gniti

onof

fires

w

arni

ngin

the

even

tof

esca

peof

haza

rdou

ssu

bsta

nces

le

akde

tect

ion

wor

kpla

cem

onito

ring

AN

N

PCA

Des

ktop

Ant

wer

pU

nive

rsity

B

elgi

um

ww

wr

st-r

osto

ckd

e

Shim

adzu

Co

MO

S6

PCA

D

eskt

op

Diag-Nose

Dia

gnos

ing

tube

rcul

osis

bo

wel

canc

ers

infe

ctio

nsin

wou

nds

and

the

urin

ary

trac

t

ww

wn

ose-

netw

ork

org

Cra

nfiel

dU

nive

rsity

B

edfo

rdsh

ire

Engl

and

Notes

MO

Sndash

met

alox

ide

sem

icon

duct

orC

Pndash

cond

uctin

gpo

lym

erQ

CM

ndashqu

artz

crys

talm

onito

rSA

Wndash

surf

ace

acou

stic

wav

eIR

ndashin

fra

red

MO

SFET

ndashm

etal

oxid

ese

mic

ondu

ctor

field

effe

ct

tran

sist

orG

Cndash

gas

chro

mat

ogra

phy

FOndash

fibre

optic

CO

ndashco

nduc

tive

olig

omer

AN

Nndash

artifi

cial

neur

alne

twor

kD

Cndash

dist

ance

clas

sifie

rsP

CA

ndashpr

inci

ple

com

pone

ntan

alys

isD

FAndash

disc

rimin

ant

func

tion

anal

ysis

C

Andash

clus

ter

anal

ysis

D

Andash

disc

rimin

ant

anal

ysis



Sensor Review


194

Table

VI

Sum

mar

yof

the

prop

ertie

sof

each

sens

orty

pere

view

ed

Sensortype

Mea

surand

Fabrication

Exam



Advantages

Disad

vantages

Referen

ce

Polymer

composites

Con

duct

ivity

Scre

enpr

intin

g

spin

coat

ing

dipc

oatin

g

spra

yco

atin

g

mic

rofa

bric

atio

n

ppb

for

HV

PGpp

mfo

rLV

PG

1pe

rce

ntD

RR

bp

pm

DL

01-

5pp

m

Ope

rate

atro

omte

mpe

ratu

re

chea

pdi

vers

era

nge

of

coat

ings

Sens

itive

tote

mpe

ratu

rean

d

hum

idity

Mun

ozet

al

(199

9)

Gar

dner

and

Dye

r(19

97)

and

Rya

net

al

(199

9)

Intrinsically

conducting

polymers

Con

duct

ivity

Elec

troc

hem

ical

chem

ical

poly

mer

isat

ion

01-

100

ppm

Sens

itive

topo

lar

anal

ytes

chea

pgo

odre

spon

setim

es

oper

ate

atro

omte

mpe

ratu

re

Sens

itive

tote

mpe

ratu

rean

d

hum

idity

su

ffer

from

base

line

drift

Nag

leet

al

(199

8)

Metal

oxides

Con

duct

ivity

Scre

enpr

intin

g

RF

sput

terin

gth

erm

al

evap

orat

ion

mic

rofa

bric

atio

n

5-50

0pp

mFa

stre

spon

sean

dre

cove

ry

times

ch

eap

Hig

hop

erat

ing

tem

pera

ture

s

suff

erfr

omsu

lphu

rpo

ison

ing

limite

dra

nge

ofco

atin

gs

Nag

leet

al

(199

8)

SAW

Piez

oele

ctric

ityPh

otol

ithog

raph

y

airb

rush

ing

scre

enpr

intin

g

dipc

oatin

gsp

inco

atin

g

1pg

to1

mg

ofva

pour

1pg

mas

s

chan

ge

DLfrac14

2pp

mfo

roc

tane

and

1pp

mN

O2

and

1pp

mH

2S

with

poly

mer

mem

bran

es

Div

erse

rang

eof

coat

ings

high

sens

itivi

ty

good

resp

onse

times

IC

inte

grat

able

Com

plex

inte

rfac

eci

rcui

try

diffi

cult

tore

prod

uce

Nag

leet

al

(199

8)

Alb

ert

and

Lew

in(2

000)

and

Penz

aet

al(

2001

a)

QCM

Piez

oele

ctric

ityM

icro

mac

hini

ng

spin

coat

ing

airb

rush

ing

inkj

etpr

intin

g

dipc

oatin

g

15

Hz

ppm

1

ngm

ass

chan

geD

iver

sera

nge

ofco

atin

gs

good

batc

hto

batc

h

repr

oduc

ibili

ty

Poor

sign

al-t

o-no

ise

ratio

com

plex

circ

uitr

y

Nag

leet

al

(199

8)an

d

Kim

and

Cho

i(2

002)

Optical

devices

Inte

nsity

spec

trum

Dip

coat

ing

Low

ppb

DL

(NH

3)frac14

1pp

mw

ith

poly

anili

neco

atin

g

Imm

une

toel

ectr

omag

netic

inte

rfer

ence

fa

stre

spon

se

times

ch

eap

light

wei

ght

Suff

erfr

omph

otob

leac

hing

com

plex

inte

rfac

eci

rcui

try

rest

ricte

dlig

htso

urce

s

Jin

etal

(2

001)

and

Nag

leet

al

(199

8)

MOSFET

Thre

shol

d

volta

ge

chan

ge

Mic

rofa

bric

atio

n

ther

mal

evap

orat

ion

28m

Vp

pmfo

rto

luen

e

DLfrac14

(am

ines

Su

lphi

des)frac14

01p

pm

Max

imum

resp

onse

frac1420

0m

V

espe

cial

lyfo

ram

ines

Smal

llo

wco

stse

nsor

sC

MO

S

inte

grat

ible

and

repr

oduc

ible

Bas

elin

edr

ift

need

cont

rolle

d

envi

ronm

ent

Cov

ingt

onet

al

(200

1)

and

Kal

man

etal

(20

00)

Notes

HV

PGndash

high

vapo

rpr

essu

rega

sLV

PGndash

low

vapo

rpr

essu

rega

sD

RR b

ndashre

lativ

edi

ffer

entia

lre

sist

ance

chan

ge



Sensor Review


195





2000)















































reviewed in Table V

Conclusions















References











Sensor Review


196






































Sensor Review


197
































Sensor Review


198

















































































et al 1997) and













composites



60 Partridge (2000)

180-240 Corcoran (1993b)




Sensor Review


186
















































2003) and 180-240 s (Corcoran 1993a)



































Sensor Review


187












Metal oxide sensors





























the surface

1






Pearce et al 2003)























































Sensor Review


188










250 and 4008C (Saha et al 2001)











1993b)

































































Figure 6 SAW sensor



Sensor Review


189






































(Dejous et al 1995)








(Nagle et al 1998)





































1998)


Df

Dcfrac14


Aeth8THORN




Sensor Review


190






(Carey 1987)



























































(Walt et al 1998)







1998)












Sensor Review


191




















































(Kalman et al 2000)































Sensor Review


192

Table

VC

hara

cter

istic

sof

com

mer

cial

e-no

ses

Man

ufacturer

Sensor

type

No

of

sensors

Applications

Pattern

recognition

commen

ts

Web

sitereferen

ceuniversity

backg

round

Airsense

analysisGmbH

MO

S10

Food

eval

uatio

nfla

vour

and

frag

ranc

ete

stin

gA

NN

D

C

PCA

Lapt

op

ww

wa

irsen

sec

om

AlphaMOS-Multi

Organ

olepticSystem

s

CP

MO

S

QC

M

SAW

6-24

Ana

lysi

sof

food

type

squ

ality

cont

rolo

ffoo

dst

orag

efr

esh

fish

and

petr

oche

mic

alpr

oduc

ts

pack

agin

gev

alua

tion

anal

ysis

of

dairy

prod

ucts

al

coho

licbe

vera

ges

and

perf

umes

AN

N

DFA

PCA

Des

ktop

ww

wa

lpha

-mos

com

Applied

Sensor

IR

MO

S

MO

SFET

QC

M

22Id

entifi

catio

nof

purit

ypr

oces

san

dqu

ality

cont

rol

envi

ronm

enta

lan

alys

is

med

ical

diag

nosi

s

AN

N

PCA

Lapt

op

ww

wa

pplie

dsen

sorc

om

Uni

vers

ityof

Link

opin

gs

Swed

en

AromaS

canPLC

CP

32En

viro

nmen

tal

mon

itorin

gch

emic

alqu

ality

cont

rol

phar

mac

eutic

alpr

oduc

tev

alua

tion

AN

N

Des

ktop

Uni

vers

ityof

Man

ches

ter

Inst

itute

ofsc

ienc

ean

dte

chno

logy

UK

Array

Tech

QC

M8

Dia

gnos

ing

lung

canc

er

food

anal

ysis

Uni

vers

ityof

Rom

e

Bloodhoundsensors

CP

14Fo

odev

alua

tion

flavo

uran

dfr

agra

nce

test

ing

mic

robi

olog

y

envi

ronm

enta

lm

onito

ring

degr

adat

ion

dete

ctio

n

AN

N

CA

PC

A

DA

Lapt

op

Uni

vers

ityof

Leed

sU

K

Cyran

oScience

Inc

CP

32Fo

odqu

ality

ch

emic

alan

alys

is

fres

hnes

ssp

oila

ge

cont

amin

atio

nde

tect

ion

cons

iste

ncy

info

ods

and

beve

rage

s

PCA

Palm

top

ww

wc

yran

osci

ence

sco

m

Cal

iforn

iain

stitu

teof

Tech

nolo

gy

USA

MarconiApplied

Technologies

QC

M

CP

MO

SSA

W

8-28

AN

N

DA

PC

AU

nive

rsity

ofW

arw

ick

UK

ElectronicSe

nsorTechnology

Inc

GC

SA

W1

Food

and

beve

rage

qual

ity

bact

eria

iden

tifica

tion

expl

osiv

es

and

drug

dete

ctio

nen

viro

nmen

tal

mon

itorin

g

SPR

Des

ktop

ww

we

stca

lcom

Forschungszen

trum

Karlsruhe

MO

SSA

W40

8

Envi

ronm

enta

lpr

otec

tion

indu

stria

lpr

oces

sco

ntro

lai

r

mon

itorin

gin

text

ilem

ills

fire

alar

ms

Qua

lity

cont

rol

info

od

prod

uctio

nA

utom

otiv

eap

plic

atio

ns

PCA

ww

wf

zkd

eFZ

K2

engl

ish

HKR-Sen

sorsystemeGmbH

QC

M6

Food

and

beve

rage

sco

smet

ics

and

perf

umes

or

gani

c

mat

eria

ls

phar

mac

eutic

alin

dust

ry

AN

N

CA

DFA

PC

A

Des

ktop

ww

wh

kr-s

enso

rde

Tech

nica

lU

nive

rsity

ofM

unic

h

Ger

man

y

Illumina

FOndash

Life

scie

nces

fo

odpr

oces

sing

ag

ricul

ture

ch

emic

alde

tect

ion

AN

Nw

ww

illu

min

aco

mTu

fts

Uni

vers

ity

USA

(Con

tinue

d)



Sensor Review


193

Table

V

Man

ufacturer

Sensor

type

No

of

sensors

Applications

Pattern

recognition

commen

ts

Web

sitereferen

ceuniversity

backg

round

Lennartz

ElectronicGmbH

MO

SQ

CM

16-4

0Fo

odan

dbe

vera

gepr

oces

sing

per

fum

eoi

lsa

gric

ultu

ralo

dour

s

and

chem

ical

anal

ysis

pr

oces

sco

ntro

l

AN

N

PCA

Des

ktop

ww

wle

nnar

tz-e

lect

roni

cde

PDF_

docu

men

ts

Uni

vers

ityof

Tubi

ngen

Marconitechnologies

MastiffElectronic

System

sLtd

CP

16Sn

iffs

palm

sfo

rpe

rson

alid

entifi

catio

nw

ww

mas

tiffc

ouk

MicrosensorSystem

sSA

W2

Che

mic

alag

ent

dete

ctio

nch

emic

alw

arfa

re(C

W)

agen

tsan

d

toxi

cin

dust

rial

chem

ical

s(T

ICs)

anal

ysis

Palm

top

ww

wm

icro

sens

orsy

stem

sco

mp

df

hazm

atca

d

OligoSe

nse

CO

ndashA

utom

otiv

eap

plic

atio

nsf

ood

eval

uatio

npa

ckag

ing

eval

uatio

nht

tp

ww

wo

ligos

ense

be

RST

Rostock

Rau

m-fah

rtund

UmweltschatzGmbH

MO

SQ

CM

SAW

6-10

Early

reco

gniti

onof

fires

w

arni

ngin

the

even

tof

esca

peof

haza

rdou

ssu

bsta

nces

le

akde

tect

ion

wor

kpla

cem

onito

ring

AN

N

PCA

Des

ktop

Ant

wer

pU

nive

rsity

B

elgi

um

ww

wr

st-r

osto

ckd

e

Shim

adzu

Co

MO

S6

PCA

D

eskt

op

Diag-Nose

Dia

gnos

ing

tube

rcul

osis

bo

wel

canc

ers

infe

ctio

nsin

wou

nds

and

the

urin

ary

trac

t

ww

wn

ose-

netw

ork

org

Cra

nfiel

dU

nive

rsity

B

edfo

rdsh

ire

Engl

and

Notes

MO

Sndash

met

alox

ide

sem

icon

duct

orC

Pndash

cond

uctin

gpo

lym

erQ

CM

ndashqu

artz

crys

talm

onito

rSA

Wndash

surf

ace

acou

stic

wav

eIR

ndashin

fra

red

MO

SFET

ndashm

etal

oxid

ese

mic

ondu

ctor

field

effe

ct

tran

sist

orG

Cndash

gas

chro

mat

ogra

phy

FOndash

fibre

optic

CO

ndashco

nduc

tive

olig

omer

AN

Nndash

artifi

cial

neur

alne

twor

kD

Cndash

dist

ance

clas

sifie

rsP

CA

ndashpr

inci

ple

com

pone

ntan

alys

isD

FAndash

disc

rimin

ant

func

tion

anal

ysis

C

Andash

clus

ter

anal

ysis

D

Andash

disc

rimin

ant

anal

ysis



Sensor Review


194

Table

VI

Sum

mar

yof

the

prop

ertie

sof

each

sens

orty

pere

view

ed

Sensortype

Mea

surand

Fabrication

Exam



Advantages

Disad

vantages

Referen

ce

Polymer

composites

Con

duct

ivity

Scre

enpr

intin

g

spin

coat

ing

dipc

oatin

g

spra

yco

atin

g

mic

rofa

bric

atio

n

ppb

for

HV

PGpp

mfo

rLV

PG

1pe

rce

ntD

RR

bp

pm

DL

01-

5pp

m

Ope

rate

atro

omte

mpe

ratu

re

chea

pdi

vers

era

nge

of

coat

ings

Sens

itive

tote

mpe

ratu

rean

d

hum

idity

Mun

ozet

al

(199

9)

Gar

dner

and

Dye

r(19

97)

and

Rya

net

al

(199

9)

Intrinsically

conducting

polymers

Con

duct

ivity

Elec

troc

hem

ical

chem

ical

poly

mer

isat

ion

01-

100

ppm

Sens

itive

topo

lar

anal

ytes

chea

pgo

odre

spon

setim

es

oper

ate

atro

omte

mpe

ratu

re

Sens

itive

tote

mpe

ratu

rean

d

hum

idity

su

ffer

from

base

line

drift

Nag

leet

al

(199

8)

Metal

oxides

Con

duct

ivity

Scre

enpr

intin

g

RF

sput

terin

gth

erm

al

evap

orat

ion

mic

rofa

bric

atio

n

5-50

0pp

mFa

stre

spon

sean

dre

cove

ry

times

ch

eap

Hig

hop

erat

ing

tem

pera

ture

s

suff

erfr

omsu

lphu

rpo

ison

ing

limite

dra

nge

ofco

atin

gs

Nag

leet

al

(199

8)

SAW

Piez

oele

ctric

ityPh

otol

ithog

raph

y

airb

rush

ing

scre

enpr

intin

g

dipc

oatin

gsp

inco

atin

g

1pg

to1

mg

ofva

pour

1pg

mas

s

chan

ge

DLfrac14

2pp

mfo

roc

tane

and

1pp

mN

O2

and

1pp

mH

2S

with

poly

mer

mem

bran

es

Div

erse

rang

eof

coat

ings

high

sens

itivi

ty

good

resp

onse

times

IC

inte

grat

able

Com

plex

inte

rfac

eci

rcui

try

diffi

cult

tore

prod

uce

Nag

leet

al

(199

8)

Alb

ert

and

Lew

in(2

000)

and

Penz

aet

al(

2001

a)

QCM

Piez

oele

ctric

ityM

icro

mac

hini

ng

spin

coat

ing

airb

rush

ing

inkj

etpr

intin

g

dipc

oatin

g

15

Hz

ppm

1

ngm

ass

chan

geD

iver

sera

nge

ofco

atin

gs

good

batc

hto

batc

h

repr

oduc

ibili

ty

Poor

sign

al-t

o-no

ise

ratio

com

plex

circ

uitr

y

Nag

leet

al

(199

8)an

d

Kim

and

Cho

i(2

002)

Optical

devices

Inte

nsity

spec

trum

Dip

coat

ing

Low

ppb

DL

(NH

3)frac14

1pp

mw

ith

poly

anili

neco

atin

g

Imm

une

toel

ectr

omag

netic

inte

rfer

ence

fa

stre

spon

se

times

ch

eap

light

wei

ght

Suff

erfr

omph

otob

leac

hing

com

plex

inte

rfac

eci

rcui

try

rest

ricte

dlig

htso

urce

s

Jin

etal

(2

001)

and

Nag

leet

al

(199

8)

MOSFET

Thre

shol

d

volta

ge

chan

ge

Mic

rofa

bric

atio

n

ther

mal

evap

orat

ion

28m

Vp

pmfo

rto

luen

e

DLfrac14

(am

ines

Su

lphi

des)frac14

01p

pm

Max

imum

resp

onse

frac1420

0m

V

espe

cial

lyfo

ram

ines

Smal

llo

wco

stse

nsor

sC

MO

S

inte

grat

ible

and

repr

oduc

ible

Bas

elin

edr

ift

need

cont

rolle

d

envi

ronm

ent

Cov

ingt

onet

al

(200

1)

and

Kal

man

etal

(20

00)

Notes

HV

PGndash

high

vapo

rpr

essu

rega

sLV

PGndash

low

vapo

rpr

essu

rega

sD

RR b

ndashre

lativ

edi

ffer

entia

lre

sist

ance

chan

ge



Sensor Review


195





2000)















































reviewed in Table V

Conclusions















References











Sensor Review


196






































Sensor Review


197
































Sensor Review


198
















































2003) and 180-240 s (Corcoran 1993a)



































Sensor Review


187












Metal oxide sensors





























the surface

1






Pearce et al 2003)























































Sensor Review


188










250 and 4008C (Saha et al 2001)











1993b)

































































Figure 6 SAW sensor



Sensor Review


189






































(Dejous et al 1995)








(Nagle et al 1998)





































1998)


Df

Dcfrac14


Aeth8THORN




Sensor Review


190






(Carey 1987)



























































(Walt et al 1998)







1998)












Sensor Review


191




















































(Kalman et al 2000)































Sensor Review


192

Table

VC

hara

cter

istic

sof

com

mer

cial

e-no

ses

Man

ufacturer

Sensor

type

No

of

sensors

Applications

Pattern

recognition

commen

ts

Web

sitereferen

ceuniversity

backg

round

Airsense

analysisGmbH

MO

S10

Food

eval

uatio

nfla

vour

and

frag

ranc

ete

stin

gA

NN

D

C

PCA

Lapt

op

ww

wa

irsen

sec

om

AlphaMOS-Multi

Organ

olepticSystem

s

CP

MO

S

QC

M

SAW

6-24

Ana

lysi

sof

food

type

squ

ality

cont

rolo

ffoo

dst

orag

efr

esh

fish

and

petr

oche

mic

alpr

oduc

ts

pack

agin

gev

alua

tion

anal

ysis

of

dairy

prod

ucts

al

coho

licbe

vera

ges

and

perf

umes

AN

N

DFA

PCA

Des

ktop

ww

wa

lpha

-mos

com

Applied

Sensor

IR

MO

S

MO

SFET

QC

M

22Id

entifi

catio

nof

purit

ypr

oces

san

dqu

ality

cont

rol

envi

ronm

enta

lan

alys

is

med

ical

diag

nosi

s

AN

N

PCA

Lapt

op

ww

wa

pplie

dsen

sorc

om

Uni

vers

ityof

Link

opin

gs

Swed

en

AromaS

canPLC

CP

32En

viro

nmen

tal

mon

itorin

gch

emic

alqu

ality

cont

rol

phar

mac

eutic

alpr

oduc

tev

alua

tion

AN

N

Des

ktop

Uni

vers

ityof

Man

ches

ter

Inst

itute

ofsc

ienc

ean

dte

chno

logy

UK

Array

Tech

QC

M8

Dia

gnos

ing

lung

canc

er

food

anal

ysis

Uni

vers

ityof

Rom

e

Bloodhoundsensors

CP

14Fo

odev

alua

tion

flavo

uran

dfr

agra

nce

test

ing

mic

robi

olog

y

envi

ronm

enta

lm

onito

ring

degr

adat

ion

dete

ctio

n

AN

N

CA

PC

A

DA

Lapt

op

Uni

vers

ityof

Leed

sU

K

Cyran

oScience

Inc

CP

32Fo

odqu

ality

ch

emic

alan

alys

is

fres

hnes

ssp

oila

ge

cont

amin

atio

nde

tect

ion

cons

iste

ncy

info

ods

and

beve

rage

s

PCA

Palm

top

ww

wc

yran

osci

ence

sco

m

Cal

iforn

iain

stitu

teof

Tech

nolo

gy

USA

MarconiApplied

Technologies

QC

M

CP

MO

SSA

W

8-28

AN

N

DA

PC

AU

nive

rsity

ofW

arw

ick

UK

ElectronicSe

nsorTechnology

Inc

GC

SA

W1

Food

and

beve

rage

qual

ity

bact

eria

iden

tifica

tion

expl

osiv

es

and

drug

dete

ctio

nen

viro

nmen

tal

mon

itorin

g

SPR

Des

ktop

ww

we

stca

lcom

Forschungszen

trum

Karlsruhe

MO

SSA

W40

8

Envi

ronm

enta

lpr

otec

tion

indu

stria

lpr

oces

sco

ntro

lai

r

mon

itorin

gin

text

ilem

ills

fire

alar

ms

Qua

lity

cont

rol

info

od

prod

uctio

nA

utom

otiv

eap

plic

atio

ns

PCA

ww

wf

zkd

eFZ

K2

engl

ish

HKR-Sen

sorsystemeGmbH

QC

M6

Food

and

beve

rage

sco

smet

ics

and

perf

umes

or

gani

c

mat

eria

ls

phar

mac

eutic

alin

dust

ry

AN

N

CA

DFA

PC

A

Des

ktop

ww

wh

kr-s

enso

rde

Tech

nica

lU

nive

rsity

ofM

unic

h

Ger

man

y

Illumina

FOndash

Life

scie

nces

fo

odpr

oces

sing

ag

ricul

ture

ch

emic

alde

tect

ion

AN

Nw

ww

illu

min

aco

mTu

fts

Uni

vers

ity

USA

(Con

tinue

d)



Sensor Review


193

Table

V

Man

ufacturer

Sensor

type

No

of

sensors

Applications

Pattern

recognition

commen

ts

Web

sitereferen

ceuniversity

backg

round

Lennartz

ElectronicGmbH

MO

SQ

CM

16-4

0Fo

odan

dbe

vera

gepr

oces

sing

per

fum

eoi

lsa

gric

ultu

ralo

dour

s

and

chem

ical

anal

ysis

pr

oces

sco

ntro

l

AN

N

PCA

Des

ktop

ww

wle

nnar

tz-e

lect

roni

cde

PDF_

docu

men

ts

Uni

vers

ityof

Tubi

ngen

Marconitechnologies

MastiffElectronic

System

sLtd

CP

16Sn

iffs

palm

sfo

rpe

rson

alid

entifi

catio

nw

ww

mas

tiffc

ouk

MicrosensorSystem

sSA

W2

Che

mic

alag

ent

dete

ctio

nch

emic

alw

arfa

re(C

W)

agen

tsan

d

toxi

cin

dust

rial

chem

ical

s(T

ICs)

anal

ysis

Palm

top

ww

wm

icro

sens

orsy

stem

sco

mp

df

hazm

atca

d

OligoSe

nse

CO

ndashA

utom

otiv

eap

plic

atio

nsf

ood

eval

uatio

npa

ckag

ing

eval

uatio

nht

tp

ww

wo

ligos

ense

be

RST

Rostock

Rau

m-fah

rtund

UmweltschatzGmbH

MO

SQ

CM

SAW

6-10

Early

reco

gniti

onof

fires

w

arni

ngin

the

even

tof

esca

peof

haza

rdou

ssu

bsta

nces

le

akde

tect

ion

wor

kpla

cem

onito

ring

AN

N

PCA

Des

ktop

Ant

wer

pU

nive

rsity

B

elgi

um

ww

wr

st-r

osto

ckd

e

Shim

adzu

Co

MO

S6

PCA

D

eskt

op

Diag-Nose

Dia

gnos

ing

tube

rcul

osis

bo

wel

canc

ers

infe

ctio

nsin

wou

nds

and

the

urin

ary

trac

t

ww

wn

ose-

netw

ork

org

Cra

nfiel

dU

nive

rsity

B

edfo

rdsh

ire

Engl

and

Notes

MO

Sndash

met

alox

ide

sem

icon

duct

orC

Pndash

cond

uctin

gpo

lym

erQ

CM

ndashqu

artz

crys

talm

onito

rSA

Wndash

surf

ace

acou

stic

wav

eIR

ndashin

fra

red

MO

SFET

ndashm

etal

oxid

ese

mic

ondu

ctor

field

effe

ct

tran

sist

orG

Cndash

gas

chro

mat

ogra

phy

FOndash

fibre

optic

CO

ndashco

nduc

tive

olig

omer

AN

Nndash

artifi

cial

neur

alne

twor

kD

Cndash

dist

ance

clas

sifie

rsP

CA

ndashpr

inci

ple

com

pone

ntan

alys

isD

FAndash

disc

rimin

ant

func

tion

anal

ysis

C

Andash

clus

ter

anal

ysis

D

Andash

disc

rimin

ant

anal

ysis



Sensor Review


194

Table

VI

Sum

mar

yof

the

prop

ertie

sof

each

sens

orty

pere

view

ed

Sensortype

Mea

surand

Fabrication

Exam



Advantages

Disad

vantages

Referen

ce

Polymer

composites

Con

duct

ivity

Scre

enpr

intin

g

spin

coat

ing

dipc

oatin

g

spra

yco

atin

g

mic

rofa

bric

atio

n

ppb

for

HV

PGpp

mfo

rLV

PG

1pe

rce

ntD

RR

bp

pm

DL

01-

5pp

m

Ope

rate

atro

omte

mpe

ratu

re

chea

pdi

vers

era

nge

of

coat

ings

Sens

itive

tote

mpe

ratu

rean

d

hum

idity

Mun

ozet

al

(199

9)

Gar

dner

and

Dye

r(19

97)

and

Rya

net

al

(199

9)

Intrinsically

conducting

polymers

Con

duct

ivity

Elec

troc

hem

ical

chem

ical

poly

mer

isat

ion

01-

100

ppm

Sens

itive

topo

lar

anal

ytes

chea

pgo

odre

spon

setim

es

oper

ate

atro

omte

mpe

ratu

re

Sens

itive

tote

mpe

ratu

rean

d

hum

idity

su

ffer

from

base

line

drift

Nag

leet

al

(199

8)

Metal

oxides

Con

duct

ivity

Scre

enpr

intin

g

RF

sput

terin

gth

erm

al

evap

orat

ion

mic

rofa

bric

atio

n

5-50

0pp

mFa

stre

spon

sean

dre

cove

ry

times

ch

eap

Hig

hop

erat

ing

tem

pera

ture

s

suff

erfr

omsu

lphu

rpo

ison

ing

limite

dra

nge

ofco

atin

gs

Nag

leet

al

(199

8)

SAW

Piez

oele

ctric

ityPh

otol

ithog

raph

y

airb

rush

ing

scre

enpr

intin

g

dipc

oatin

gsp

inco

atin

g

1pg

to1

mg

ofva

pour

1pg

mas

s

chan

ge

DLfrac14

2pp

mfo

roc

tane

and

1pp

mN

O2

and

1pp

mH

2S

with

poly

mer

mem

bran

es

Div

erse

rang

eof

coat

ings

high

sens

itivi

ty

good

resp

onse

times

IC

inte

grat

able

Com

plex

inte

rfac

eci

rcui

try

diffi

cult

tore

prod

uce

Nag

leet

al

(199

8)

Alb

ert

and

Lew

in(2

000)

and

Penz

aet

al(

2001

a)

QCM

Piez

oele

ctric

ityM

icro

mac

hini

ng

spin

coat

ing

airb

rush

ing

inkj

etpr

intin

g

dipc

oatin

g

15

Hz

ppm

1

ngm

ass

chan

geD

iver

sera

nge

ofco

atin

gs

good

batc

hto

batc

h

repr

oduc

ibili

ty

Poor

sign

al-t

o-no

ise

ratio

com

plex

circ

uitr

y

Nag

leet

al

(199

8)an

d

Kim

and

Cho

i(2

002)

Optical

devices

Inte

nsity

spec

trum

Dip

coat

ing

Low

ppb

DL

(NH

3)frac14

1pp

mw

ith

poly

anili

neco

atin

g

Imm

une

toel

ectr

omag

netic

inte

rfer

ence

fa

stre

spon

se

times

ch

eap

light

wei

ght

Suff

erfr

omph

otob

leac

hing

com

plex

inte

rfac

eci

rcui

try

rest

ricte

dlig

htso

urce

s

Jin

etal

(2

001)

and

Nag

leet

al

(199

8)

MOSFET

Thre

shol

d

volta

ge

chan

ge

Mic

rofa

bric

atio

n

ther

mal

evap

orat

ion

28m

Vp

pmfo

rto

luen

e

DLfrac14

(am

ines

Su

lphi

des)frac14

01p

pm

Max

imum

resp

onse

frac1420

0m

V

espe

cial

lyfo

ram

ines

Smal

llo

wco

stse

nsor

sC

MO

S

inte

grat

ible

and

repr

oduc

ible

Bas

elin

edr

ift

need

cont

rolle

d

envi

ronm

ent

Cov

ingt

onet

al

(200

1)

and

Kal

man

etal

(20

00)

Notes

HV

PGndash

high

vapo

rpr

essu

rega

sLV

PGndash

low

vapo

rpr

essu

rega

sD

RR b

ndashre

lativ

edi

ffer

entia

lre

sist

ance

chan

ge



Sensor Review


195





2000)















































reviewed in Table V

Conclusions















References











Sensor Review


196






































Sensor Review


197
































Sensor Review


198












Metal oxide sensors





























the surface

1






Pearce et al 2003)























































Sensor Review


188










250 and 4008C (Saha et al 2001)











1993b)

































































Figure 6 SAW sensor



Sensor Review


189






































(Dejous et al 1995)








(Nagle et al 1998)





































1998)


Df

Dcfrac14


Aeth8THORN




Sensor Review


190






(Carey 1987)



























































(Walt et al 1998)







1998)












Sensor Review


191




















































(Kalman et al 2000)































Sensor Review


192

Table

VC

hara

cter

istic

sof

com

mer

cial

e-no

ses

Man

ufacturer

Sensor

type

No

of

sensors

Applications

Pattern

recognition

commen

ts

Web

sitereferen

ceuniversity

backg

round

Airsense

analysisGmbH

MO

S10

Food

eval

uatio

nfla

vour

and

frag

ranc

ete

stin

gA

NN

D

C

PCA

Lapt

op

ww

wa

irsen

sec

om

AlphaMOS-Multi

Organ

olepticSystem

s

CP

MO

S

QC

M

SAW

6-24

Ana

lysi

sof

food

type

squ

ality

cont

rolo

ffoo

dst

orag

efr

esh

fish

and

petr

oche

mic

alpr

oduc

ts

pack

agin

gev

alua

tion

anal

ysis

of

dairy

prod

ucts

al

coho

licbe

vera

ges

and

perf

umes

AN

N

DFA

PCA

Des

ktop

ww

wa

lpha

-mos

com

Applied

Sensor

IR

MO

S

MO

SFET

QC

M

22Id

entifi

catio

nof

purit

ypr

oces

san

dqu

ality

cont

rol

envi

ronm

enta

lan

alys

is

med

ical

diag

nosi

s

AN

N

PCA

Lapt

op

ww

wa

pplie

dsen

sorc

om

Uni

vers

ityof

Link

opin

gs

Swed

en

AromaS

canPLC

CP

32En

viro

nmen

tal

mon

itorin

gch

emic

alqu

ality

cont

rol

phar

mac

eutic

alpr

oduc

tev

alua

tion

AN

N

Des

ktop

Uni

vers

ityof

Man

ches

ter

Inst

itute

ofsc

ienc

ean

dte

chno

logy

UK

Array

Tech

QC

M8

Dia

gnos

ing

lung

canc

er

food

anal

ysis

Uni

vers

ityof

Rom

e

Bloodhoundsensors

CP

14Fo

odev

alua

tion

flavo

uran

dfr

agra

nce

test

ing

mic

robi

olog

y

envi

ronm

enta

lm

onito

ring

degr

adat

ion

dete

ctio

n

AN

N

CA

PC

A

DA

Lapt

op

Uni

vers

ityof

Leed

sU

K

Cyran

oScience

Inc

CP

32Fo

odqu

ality

ch

emic

alan

alys

is

fres

hnes

ssp

oila

ge

cont

amin

atio

nde

tect

ion

cons

iste

ncy

info

ods

and

beve

rage

s

PCA

Palm

top

ww

wc

yran

osci

ence

sco

m

Cal

iforn

iain

stitu

teof

Tech

nolo

gy

USA

MarconiApplied

Technologies

QC

M

CP

MO

SSA

W

8-28

AN

N

DA

PC

AU

nive

rsity

ofW

arw

ick

UK

ElectronicSe

nsorTechnology

Inc

GC

SA

W1

Food

and

beve

rage

qual

ity

bact

eria

iden

tifica

tion

expl

osiv

es

and

drug

dete

ctio

nen

viro

nmen

tal

mon

itorin

g

SPR

Des

ktop

ww

we

stca

lcom

Forschungszen

trum

Karlsruhe

MO

SSA

W40

8

Envi

ronm

enta

lpr

otec

tion

indu

stria

lpr

oces

sco

ntro

lai

r

mon

itorin

gin

text

ilem

ills

fire

alar

ms

Qua

lity

cont

rol

info

od

prod

uctio

nA

utom

otiv

eap

plic

atio

ns

PCA

ww

wf

zkd

eFZ

K2

engl

ish

HKR-Sen

sorsystemeGmbH

QC

M6

Food

and

beve

rage

sco

smet

ics

and

perf

umes

or

gani

c

mat

eria

ls

phar

mac

eutic

alin

dust

ry

AN

N

CA

DFA

PC

A

Des

ktop

ww

wh

kr-s

enso

rde

Tech

nica

lU

nive

rsity

ofM

unic

h

Ger

man

y

Illumina

FOndash

Life

scie

nces

fo

odpr

oces

sing

ag

ricul

ture

ch

emic

alde

tect

ion

AN

Nw

ww

illu

min

aco

mTu

fts

Uni

vers

ity

USA

(Con

tinue

d)



Sensor Review


193

Table

V

Man

ufacturer

Sensor

type

No

of

sensors

Applications

Pattern

recognition

commen

ts

Web

sitereferen

ceuniversity

backg

round

Lennartz

ElectronicGmbH

MO

SQ

CM

16-4

0Fo

odan

dbe

vera

gepr

oces

sing

per

fum

eoi

lsa

gric

ultu

ralo

dour

s

and

chem

ical

anal

ysis

pr

oces

sco

ntro

l

AN

N

PCA

Des

ktop

ww

wle

nnar

tz-e

lect

roni

cde

PDF_

docu

men

ts

Uni

vers

ityof

Tubi

ngen

Marconitechnologies

MastiffElectronic

System

sLtd

CP

16Sn

iffs

palm

sfo

rpe

rson

alid

entifi

catio

nw

ww

mas

tiffc

ouk

MicrosensorSystem

sSA

W2

Che

mic

alag

ent

dete

ctio

nch

emic

alw

arfa

re(C

W)

agen

tsan

d

toxi

cin

dust

rial

chem

ical

s(T

ICs)

anal

ysis

Palm

top

ww

wm

icro

sens

orsy

stem

sco

mp

df

hazm

atca

d

OligoSe

nse

CO

ndashA

utom

otiv

eap

plic

atio

nsf

ood

eval

uatio

npa

ckag

ing

eval

uatio

nht

tp

ww

wo

ligos

ense

be

RST

Rostock

Rau

m-fah

rtund

UmweltschatzGmbH

MO

SQ

CM

SAW

6-10

Early

reco

gniti

onof

fires

w

arni

ngin

the

even

tof

esca

peof

haza

rdou

ssu

bsta

nces

le

akde

tect

ion

wor

kpla

cem

onito

ring

AN

N

PCA

Des

ktop

Ant

wer

pU

nive

rsity

B

elgi

um

ww

wr

st-r

osto

ckd

e

Shim

adzu

Co

MO

S6

PCA

D

eskt

op

Diag-Nose

Dia

gnos

ing

tube

rcul

osis

bo

wel

canc

ers

infe

ctio

nsin

wou

nds

and

the

urin

ary

trac

t

ww

wn

ose-

netw

ork

org

Cra

nfiel

dU

nive

rsity

B

edfo

rdsh

ire

Engl

and

Notes

MO

Sndash

met

alox

ide

sem

icon

duct

orC

Pndash

cond

uctin

gpo

lym

erQ

CM

ndashqu

artz

crys

talm

onito

rSA

Wndash

surf

ace

acou

stic

wav

eIR

ndashin

fra

red

MO

SFET

ndashm

etal

oxid

ese

mic

ondu

ctor

field

effe

ct

tran

sist

orG

Cndash

gas

chro

mat

ogra

phy

FOndash

fibre

optic

CO

ndashco

nduc

tive

olig

omer

AN

Nndash

artifi

cial

neur

alne

twor

kD

Cndash

dist

ance

clas

sifie

rsP

CA

ndashpr

inci

ple

com

pone

ntan

alys

isD

FAndash

disc

rimin

ant

func

tion

anal

ysis

C

Andash

clus

ter

anal

ysis

D

Andash

disc

rimin

ant

anal

ysis



Sensor Review


194

Table

VI

Sum

mar

yof

the

prop

ertie

sof

each

sens

orty

pere

view

ed

Sensortype

Mea

surand

Fabrication

Exam



Advantages

Disad

vantages

Referen

ce

Polymer

composites

Con

duct

ivity

Scre

enpr

intin

g

spin

coat

ing

dipc

oatin

g

spra

yco

atin

g

mic

rofa

bric

atio

n

ppb

for

HV

PGpp

mfo

rLV

PG

1pe

rce

ntD

RR

bp

pm

DL

01-

5pp

m

Ope

rate

atro

omte

mpe

ratu

re

chea

pdi

vers

era

nge

of

coat

ings

Sens

itive

tote

mpe

ratu

rean

d

hum

idity

Mun

ozet

al

(199

9)

Gar

dner

and

Dye

r(19

97)

and

Rya

net

al

(199

9)

Intrinsically

conducting

polymers

Con

duct

ivity

Elec

troc

hem

ical

chem

ical

poly

mer

isat

ion

01-

100

ppm

Sens

itive

topo

lar

anal

ytes

chea

pgo

odre

spon

setim

es

oper

ate

atro

omte

mpe

ratu

re

Sens

itive

tote

mpe

ratu

rean

d

hum

idity

su

ffer

from

base

line

drift

Nag

leet

al

(199

8)

Metal

oxides

Con

duct

ivity

Scre

enpr

intin

g

RF

sput

terin

gth

erm

al

evap

orat

ion

mic

rofa

bric

atio

n

5-50

0pp

mFa

stre

spon

sean

dre

cove

ry

times

ch

eap

Hig

hop

erat

ing

tem

pera

ture

s

suff

erfr

omsu

lphu

rpo

ison

ing

limite

dra

nge

ofco

atin

gs

Nag

leet

al

(199

8)

SAW

Piez

oele

ctric

ityPh

otol

ithog

raph

y

airb

rush

ing

scre

enpr

intin

g

dipc

oatin

gsp

inco

atin

g

1pg

to1

mg

ofva

pour

1pg

mas

s

chan

ge

DLfrac14

2pp

mfo

roc

tane

and

1pp

mN

O2

and

1pp

mH

2S

with

poly

mer

mem

bran

es

Div

erse

rang

eof

coat

ings

high

sens

itivi

ty

good

resp

onse

times

IC

inte

grat

able

Com

plex

inte

rfac

eci

rcui

try

diffi

cult

tore

prod

uce

Nag

leet

al

(199

8)

Alb

ert

and

Lew

in(2

000)

and

Penz

aet

al(

2001

a)

QCM

Piez

oele

ctric

ityM

icro

mac

hini

ng

spin

coat

ing

airb

rush

ing

inkj

etpr

intin

g

dipc

oatin

g

15

Hz

ppm

1

ngm

ass

chan

geD

iver

sera

nge

ofco

atin

gs

good

batc

hto

batc

h

repr

oduc

ibili

ty

Poor

sign

al-t

o-no

ise

ratio

com

plex

circ

uitr

y

Nag

leet

al

(199

8)an

d

Kim

and

Cho

i(2

002)

Optical

devices

Inte

nsity

spec

trum

Dip

coat

ing

Low

ppb

DL

(NH

3)frac14

1pp

mw

ith

poly

anili

neco

atin

g

Imm

une

toel

ectr

omag

netic

inte

rfer

ence

fa

stre

spon

se

times

ch

eap

light

wei

ght

Suff

erfr

omph

otob

leac

hing

com

plex

inte

rfac

eci

rcui

try

rest

ricte

dlig

htso

urce

s

Jin

etal

(2

001)

and

Nag

leet

al

(199

8)

MOSFET

Thre

shol

d

volta

ge

chan

ge

Mic

rofa

bric

atio

n

ther

mal

evap

orat

ion

28m

Vp

pmfo

rto

luen

e

DLfrac14

(am

ines

Su

lphi

des)frac14

01p

pm

Max

imum

resp

onse

frac1420

0m

V

espe

cial

lyfo

ram

ines

Smal

llo

wco

stse

nsor

sC

MO

S

inte

grat

ible

and

repr

oduc

ible

Bas

elin

edr

ift

need

cont

rolle

d

envi

ronm

ent

Cov

ingt

onet

al

(200

1)

and

Kal

man

etal

(20

00)

Notes

HV

PGndash

high

vapo

rpr

essu

rega

sLV

PGndash

low

vapo

rpr

essu

rega

sD

RR b

ndashre

lativ

edi

ffer

entia

lre

sist

ance

chan

ge



Sensor Review


195





2000)















































reviewed in Table V

Conclusions















References











Sensor Review


196






































Sensor Review


197
































Sensor Review


198










250 and 4008C (Saha et al 2001)











1993b)

































































Figure 6 SAW sensor



Sensor Review


189






































(Dejous et al 1995)








(Nagle et al 1998)





































1998)


Df

Dcfrac14


Aeth8THORN




Sensor Review


190






(Carey 1987)



























































(Walt et al 1998)







1998)












Sensor Review


191




















































(Kalman et al 2000)































Sensor Review


192

Table

VC

hara

cter

istic

sof

com

mer

cial

e-no

ses

Man

ufacturer

Sensor

type

No

of

sensors

Applications

Pattern

recognition

commen

ts

Web

sitereferen

ceuniversity

backg

round

Airsense

analysisGmbH

MO

S10

Food

eval

uatio

nfla

vour

and

frag

ranc

ete

stin

gA

NN

D

C

PCA

Lapt

op

ww

wa

irsen

sec

om

AlphaMOS-Multi

Organ

olepticSystem

s

CP

MO

S

QC

M

SAW

6-24

Ana

lysi

sof

food

type

squ

ality

cont

rolo

ffoo

dst

orag

efr

esh

fish

and

petr

oche

mic

alpr

oduc

ts

pack

agin

gev

alua

tion

anal

ysis

of

dairy

prod

ucts

al

coho

licbe

vera

ges

and

perf

umes

AN

N

DFA

PCA

Des

ktop

ww

wa

lpha

-mos

com

Applied

Sensor

IR

MO

S

MO

SFET

QC

M

22Id

entifi

catio

nof

purit

ypr

oces

san

dqu

ality

cont

rol

envi

ronm

enta

lan

alys

is

med

ical

diag

nosi

s

AN

N

PCA

Lapt

op

ww

wa

pplie

dsen

sorc

om

Uni

vers

ityof

Link

opin

gs

Swed

en

AromaS

canPLC

CP

32En

viro

nmen

tal

mon

itorin

gch

emic

alqu

ality

cont

rol

phar

mac

eutic

alpr

oduc

tev

alua

tion

AN

N

Des

ktop

Uni

vers

ityof

Man

ches

ter

Inst

itute

ofsc

ienc

ean

dte

chno

logy

UK

Array

Tech

QC

M8

Dia

gnos

ing

lung

canc

er

food

anal

ysis

Uni

vers

ityof

Rom

e

Bloodhoundsensors

CP

14Fo

odev

alua

tion

flavo

uran

dfr

agra

nce

test

ing

mic

robi

olog

y

envi

ronm

enta

lm

onito

ring

degr

adat

ion

dete

ctio

n

AN

N

CA

PC

A

DA

Lapt

op

Uni

vers

ityof

Leed

sU

K

Cyran

oScience

Inc

CP

32Fo

odqu

ality

ch

emic

alan

alys

is

fres

hnes

ssp

oila

ge

cont

amin

atio

nde

tect

ion

cons

iste

ncy

info

ods

and

beve

rage

s

PCA

Palm

top

ww

wc

yran

osci

ence

sco

m

Cal

iforn

iain

stitu

teof

Tech

nolo

gy

USA

MarconiApplied

Technologies

QC

M

CP

MO

SSA

W

8-28

AN

N

DA

PC

AU

nive

rsity

ofW

arw

ick

UK

ElectronicSe

nsorTechnology

Inc

GC

SA

W1

Food

and

beve

rage

qual

ity

bact

eria

iden

tifica

tion

expl

osiv

es

and

drug

dete

ctio

nen

viro

nmen

tal

mon

itorin

g

SPR

Des

ktop

ww

we

stca

lcom

Forschungszen

trum

Karlsruhe

MO

SSA

W40

8

Envi

ronm

enta

lpr

otec

tion

indu

stria

lpr

oces

sco

ntro

lai

r

mon

itorin

gin

text

ilem

ills

fire

alar

ms

Qua

lity

cont

rol

info

od

prod

uctio

nA

utom

otiv

eap

plic

atio

ns

PCA

ww

wf

zkd

eFZ

K2

engl

ish

HKR-Sen

sorsystemeGmbH

QC

M6

Food

and

beve

rage

sco

smet

ics

and

perf

umes

or

gani

c

mat

eria

ls

phar

mac

eutic

alin

dust

ry

AN

N

CA

DFA

PC

A

Des

ktop

ww

wh

kr-s

enso

rde

Tech

nica

lU

nive

rsity

ofM

unic

h

Ger

man

y

Illumina

FOndash

Life

scie

nces

fo

odpr

oces

sing

ag

ricul

ture

ch

emic

alde

tect

ion

AN

Nw

ww

illu

min

aco

mTu

fts

Uni

vers

ity

USA

(Con

tinue

d)



Sensor Review


193

Table

V

Man

ufacturer

Sensor

type

No

of

sensors

Applications

Pattern

recognition

commen

ts

Web

sitereferen

ceuniversity

backg

round

Lennartz

ElectronicGmbH

MO

SQ

CM

16-4

0Fo

odan

dbe

vera

gepr

oces

sing

per

fum

eoi

lsa

gric

ultu

ralo

dour

s

and

chem

ical

anal

ysis

pr

oces

sco

ntro

l

AN

N

PCA

Des

ktop

ww

wle

nnar

tz-e

lect

roni

cde

PDF_

docu

men

ts

Uni

vers

ityof

Tubi

ngen

Marconitechnologies

MastiffElectronic

System

sLtd

CP

16Sn

iffs

palm

sfo

rpe

rson

alid

entifi

catio

nw

ww

mas

tiffc

ouk

MicrosensorSystem

sSA

W2

Che

mic

alag

ent

dete

ctio

nch

emic

alw

arfa

re(C

W)

agen

tsan

d

toxi

cin

dust

rial

chem

ical

s(T

ICs)

anal

ysis

Palm

top

ww

wm

icro

sens

orsy

stem

sco

mp

df

hazm

atca

d

OligoSe

nse

CO

ndashA

utom

otiv

eap

plic

atio

nsf

ood

eval

uatio

npa

ckag

ing

eval

uatio

nht

tp

ww

wo

ligos

ense

be

RST

Rostock

Rau

m-fah

rtund

UmweltschatzGmbH

MO

SQ

CM

SAW

6-10

Early

reco

gniti

onof

fires

w

arni

ngin

the

even

tof

esca

peof

haza

rdou

ssu

bsta

nces

le

akde

tect

ion

wor

kpla

cem

onito

ring

AN

N

PCA

Des

ktop

Ant

wer

pU

nive

rsity

B

elgi

um

ww

wr

st-r

osto

ckd

e

Shim

adzu

Co

MO

S6

PCA

D

eskt

op

Diag-Nose

Dia

gnos

ing

tube

rcul

osis

bo

wel

canc

ers

infe

ctio

nsin

wou

nds

and

the

urin

ary

trac

t

ww

wn

ose-

netw

ork

org

Cra

nfiel

dU

nive

rsity

B

edfo

rdsh

ire

Engl

and

Notes

MO

Sndash

met

alox

ide

sem

icon

duct

orC

Pndash

cond

uctin

gpo

lym

erQ

CM

ndashqu

artz

crys

talm

onito

rSA

Wndash

surf

ace

acou

stic

wav

eIR

ndashin

fra

red

MO

SFET

ndashm

etal

oxid

ese

mic

ondu

ctor

field

effe

ct

tran

sist

orG

Cndash

gas

chro

mat

ogra

phy

FOndash

fibre

optic

CO

ndashco

nduc

tive

olig

omer

AN

Nndash

artifi

cial

neur

alne

twor

kD

Cndash

dist

ance

clas

sifie

rsP

CA

ndashpr

inci

ple

com

pone

ntan

alys

isD

FAndash

disc

rimin

ant

func

tion

anal

ysis

C

Andash

clus

ter

anal

ysis

D

Andash

disc

rimin

ant

anal

ysis



Sensor Review


194

Table

VI

Sum

mar

yof

the

prop

ertie

sof

each

sens

orty

pere

view

ed

Sensortype

Mea

surand

Fabrication

Exam



Advantages

Disad

vantages

Referen

ce

Polymer

composites

Con

duct

ivity

Scre

enpr

intin

g

spin

coat

ing

dipc

oatin

g

spra

yco

atin

g

mic

rofa

bric

atio

n

ppb

for

HV

PGpp

mfo

rLV

PG

1pe

rce

ntD

RR

bp

pm

DL

01-

5pp

m

Ope

rate

atro

omte

mpe

ratu

re

chea

pdi

vers

era

nge

of

coat

ings

Sens

itive

tote

mpe

ratu

rean

d

hum

idity

Mun

ozet

al

(199

9)

Gar

dner

and

Dye

r(19

97)

and

Rya

net

al

(199

9)

Intrinsically

conducting

polymers

Con

duct

ivity

Elec

troc

hem

ical

chem

ical

poly

mer

isat

ion

01-

100

ppm

Sens

itive

topo

lar

anal

ytes

chea

pgo

odre

spon

setim

es

oper

ate

atro

omte

mpe

ratu

re

Sens

itive

tote

mpe

ratu

rean

d

hum

idity

su

ffer

from

base

line

drift

Nag

leet

al

(199

8)

Metal

oxides

Con

duct

ivity

Scre

enpr

intin

g

RF

sput

terin

gth

erm

al

evap

orat

ion

mic

rofa

bric

atio

n

5-50

0pp

mFa

stre

spon

sean

dre

cove

ry

times

ch

eap

Hig

hop

erat

ing

tem

pera

ture

s

suff

erfr

omsu

lphu

rpo

ison

ing

limite

dra

nge

ofco

atin

gs

Nag

leet

al

(199

8)

SAW

Piez

oele

ctric

ityPh

otol

ithog

raph

y

airb

rush

ing

scre

enpr

intin

g

dipc

oatin

gsp

inco

atin

g

1pg

to1

mg

ofva

pour

1pg

mas

s

chan

ge

DLfrac14

2pp

mfo

roc

tane

and

1pp

mN

O2

and

1pp

mH

2S

with

poly

mer

mem

bran

es

Div

erse

rang

eof

coat

ings

high

sens

itivi

ty

good

resp

onse

times

IC

inte

grat

able

Com

plex

inte

rfac

eci

rcui

try

diffi

cult

tore

prod

uce

Nag

leet

al

(199

8)

Alb

ert

and

Lew

in(2

000)

and

Penz

aet

al(

2001

a)

QCM

Piez

oele

ctric

ityM

icro

mac

hini

ng

spin

coat

ing

airb

rush

ing

inkj

etpr

intin

g

dipc

oatin

g

15

Hz

ppm

1

ngm

ass

chan

geD

iver

sera

nge

ofco

atin

gs

good

batc

hto

batc

h

repr

oduc

ibili

ty

Poor

sign

al-t

o-no

ise

ratio

com

plex

circ

uitr

y

Nag

leet

al

(199

8)an

d

Kim

and

Cho

i(2

002)

Optical

devices

Inte

nsity

spec

trum

Dip

coat

ing

Low

ppb

DL

(NH

3)frac14

1pp

mw

ith

poly

anili

neco

atin

g

Imm

une

toel

ectr

omag

netic

inte

rfer

ence

fa

stre

spon

se

times

ch

eap

light

wei

ght

Suff

erfr

omph

otob

leac

hing

com

plex

inte

rfac

eci

rcui

try

rest

ricte

dlig

htso

urce

s

Jin

etal

(2

001)

and

Nag

leet

al

(199

8)

MOSFET

Thre

shol

d

volta

ge

chan

ge

Mic

rofa

bric

atio

n

ther

mal

evap

orat

ion

28m

Vp

pmfo

rto

luen

e

DLfrac14

(am

ines

Su

lphi

des)frac14

01p

pm

Max

imum

resp

onse

frac1420

0m

V

espe

cial

lyfo

ram

ines

Smal

llo

wco

stse

nsor

sC

MO

S

inte

grat

ible

and

repr

oduc

ible

Bas

elin

edr

ift

need

cont

rolle

d

envi

ronm

ent

Cov

ingt

onet

al

(200

1)

and

Kal

man

etal

(20

00)

Notes

HV

PGndash

high

vapo

rpr

essu

rega

sLV

PGndash

low

vapo

rpr

essu

rega

sD

RR b

ndashre

lativ

edi

ffer

entia

lre

sist

ance

chan

ge



Sensor Review


195





2000)















































reviewed in Table V

Conclusions















References











Sensor Review


196






































Sensor Review


197
































Sensor Review


198






































(Dejous et al 1995)








(Nagle et al 1998)





































1998)


Df

Dcfrac14


Aeth8THORN




Sensor Review


190






(Carey 1987)



























































(Walt et al 1998)







1998)












Sensor Review


191




















































(Kalman et al 2000)































Sensor Review


192

Table

VC

hara

cter

istic

sof

com

mer

cial

e-no

ses

Man

ufacturer

Sensor

type

No

of

sensors

Applications

Pattern

recognition

commen

ts

Web

sitereferen

ceuniversity

backg

round

Airsense

analysisGmbH

MO

S10

Food

eval

uatio

nfla

vour

and

frag

ranc

ete

stin

gA

NN

D

C

PCA

Lapt

op

ww

wa

irsen

sec

om

AlphaMOS-Multi

Organ

olepticSystem

s

CP

MO

S

QC

M

SAW

6-24

Ana

lysi

sof

food

type

squ

ality

cont

rolo

ffoo

dst

orag

efr

esh

fish

and

petr

oche

mic

alpr

oduc

ts

pack

agin

gev

alua

tion

anal

ysis

of

dairy

prod

ucts

al

coho

licbe

vera

ges

and

perf

umes

AN

N

DFA

PCA

Des

ktop

ww

wa

lpha

-mos

com

Applied

Sensor

IR

MO

S

MO

SFET

QC

M

22Id

entifi

catio

nof

purit

ypr

oces

san

dqu

ality

cont

rol

envi

ronm

enta

lan

alys

is

med

ical

diag

nosi

s

AN

N

PCA

Lapt

op

ww

wa

pplie

dsen

sorc

om

Uni

vers

ityof

Link

opin

gs

Swed

en

AromaS

canPLC

CP

32En

viro

nmen

tal

mon

itorin

gch

emic

alqu

ality

cont

rol

phar

mac

eutic

alpr

oduc

tev

alua

tion

AN

N

Des

ktop

Uni

vers

ityof

Man

ches

ter

Inst

itute

ofsc

ienc

ean

dte

chno

logy

UK

Array

Tech

QC

M8

Dia

gnos

ing

lung

canc

er

food

anal

ysis

Uni

vers

ityof

Rom

e

Bloodhoundsensors

CP

14Fo

odev

alua

tion

flavo

uran

dfr

agra

nce

test

ing

mic

robi

olog

y

envi

ronm

enta

lm

onito

ring

degr

adat

ion

dete

ctio

n

AN

N

CA

PC

A

DA

Lapt

op

Uni

vers

ityof

Leed

sU

K

Cyran

oScience

Inc

CP

32Fo

odqu

ality

ch

emic

alan

alys

is

fres

hnes

ssp

oila

ge

cont

amin

atio

nde

tect

ion

cons

iste

ncy

info

ods

and

beve

rage

s

PCA

Palm

top

ww

wc

yran

osci

ence

sco

m

Cal

iforn

iain

stitu

teof

Tech

nolo

gy

USA

MarconiApplied

Technologies

QC

M

CP

MO

SSA

W

8-28

AN

N

DA

PC

AU

nive

rsity

ofW

arw

ick

UK

ElectronicSe

nsorTechnology

Inc

GC

SA

W1

Food

and

beve

rage

qual

ity

bact

eria

iden

tifica

tion

expl

osiv

es

and

drug

dete

ctio

nen

viro

nmen

tal

mon

itorin

g

SPR

Des

ktop

ww

we

stca

lcom

Forschungszen

trum

Karlsruhe

MO

SSA

W40

8

Envi

ronm

enta

lpr

otec

tion

indu

stria

lpr

oces

sco

ntro

lai

r

mon

itorin

gin

text

ilem

ills

fire

alar

ms

Qua

lity

cont

rol

info

od

prod

uctio

nA

utom

otiv

eap

plic

atio

ns

PCA

ww

wf

zkd

eFZ

K2

engl

ish

HKR-Sen

sorsystemeGmbH

QC

M6

Food

and

beve

rage

sco

smet

ics

and

perf

umes

or

gani

c

mat

eria

ls

phar

mac

eutic

alin

dust

ry

AN

N

CA

DFA

PC

A

Des

ktop

ww

wh

kr-s

enso

rde

Tech

nica

lU

nive

rsity

ofM

unic

h

Ger

man

y

Illumina

FOndash

Life

scie

nces

fo

odpr

oces

sing

ag

ricul

ture

ch

emic

alde

tect

ion

AN

Nw

ww

illu

min

aco

mTu

fts

Uni

vers

ity

USA

(Con

tinue

d)



Sensor Review


193

Table

V

Man

ufacturer

Sensor

type

No

of

sensors

Applications

Pattern

recognition

commen

ts

Web

sitereferen

ceuniversity

backg

round

Lennartz

ElectronicGmbH

MO

SQ

CM

16-4

0Fo

odan

dbe

vera

gepr

oces

sing

per

fum

eoi

lsa

gric

ultu

ralo

dour

s

and

chem

ical

anal

ysis

pr

oces

sco

ntro

l

AN

N

PCA

Des

ktop

ww

wle

nnar

tz-e

lect

roni

cde

PDF_

docu

men

ts

Uni

vers

ityof

Tubi

ngen

Marconitechnologies

MastiffElectronic

System

sLtd

CP

16Sn

iffs

palm

sfo

rpe

rson

alid

entifi

catio

nw

ww

mas

tiffc

ouk

MicrosensorSystem

sSA

W2

Che

mic

alag

ent

dete

ctio

nch

emic

alw

arfa

re(C

W)

agen

tsan

d

toxi

cin

dust

rial

chem

ical

s(T

ICs)

anal

ysis

Palm

top

ww

wm

icro

sens

orsy

stem

sco

mp

df

hazm

atca

d

OligoSe

nse

CO

ndashA

utom

otiv

eap

plic

atio

nsf

ood

eval

uatio

npa

ckag

ing

eval

uatio

nht

tp

ww

wo

ligos

ense

be

RST

Rostock

Rau

m-fah

rtund

UmweltschatzGmbH

MO

SQ

CM

SAW

6-10

Early

reco

gniti

onof

fires

w

arni

ngin

the

even

tof

esca

peof

haza

rdou

ssu

bsta

nces

le

akde

tect

ion

wor

kpla

cem

onito

ring

AN

N

PCA

Des

ktop

Ant

wer

pU

nive

rsity

B

elgi

um

ww

wr

st-r

osto

ckd

e

Shim

adzu

Co

MO

S6

PCA

D

eskt

op

Diag-Nose

Dia

gnos

ing

tube

rcul

osis

bo

wel

canc

ers

infe

ctio

nsin

wou

nds

and

the

urin

ary

trac

t

ww

wn

ose-

netw

ork

org

Cra

nfiel

dU

nive

rsity

B

edfo

rdsh

ire

Engl

and

Notes

MO

Sndash

met

alox

ide

sem

icon

duct

orC

Pndash

cond

uctin

gpo

lym

erQ

CM

ndashqu

artz

crys

talm

onito

rSA

Wndash

surf

ace

acou

stic

wav

eIR

ndashin

fra

red

MO

SFET

ndashm

etal

oxid

ese

mic

ondu

ctor

field

effe

ct

tran

sist

orG

Cndash

gas

chro

mat

ogra

phy

FOndash

fibre

optic

CO

ndashco

nduc

tive

olig

omer

AN

Nndash

artifi

cial

neur

alne

twor

kD

Cndash

dist

ance

clas

sifie

rsP

CA

ndashpr

inci

ple

com

pone

ntan

alys

isD

FAndash

disc

rimin

ant

func

tion

anal

ysis

C

Andash

clus

ter

anal

ysis

D

Andash

disc

rimin

ant

anal

ysis



Sensor Review


194

Table

VI

Sum

mar

yof

the

prop

ertie

sof

each

sens

orty

pere

view

ed

Sensortype

Mea

surand

Fabrication

Exam



Advantages

Disad

vantages

Referen

ce

Polymer

composites

Con

duct

ivity

Scre

enpr

intin

g

spin

coat

ing

dipc

oatin

g

spra

yco

atin

g

mic

rofa

bric

atio

n

ppb

for

HV

PGpp

mfo

rLV

PG

1pe

rce

ntD

RR

bp

pm

DL

01-

5pp

m

Ope

rate

atro

omte

mpe

ratu

re

chea

pdi

vers

era

nge

of

coat

ings

Sens

itive

tote

mpe

ratu

rean

d

hum

idity

Mun

ozet

al

(199

9)

Gar

dner

and

Dye

r(19

97)

and

Rya

net

al

(199

9)

Intrinsically

conducting

polymers

Con

duct

ivity

Elec

troc

hem

ical

chem

ical

poly

mer

isat

ion

01-

100

ppm

Sens

itive

topo

lar

anal

ytes

chea

pgo

odre

spon

setim

es

oper

ate

atro

omte

mpe

ratu

re

Sens

itive

tote

mpe

ratu

rean

d

hum

idity

su

ffer

from

base

line

drift

Nag

leet

al

(199

8)

Metal

oxides

Con

duct

ivity

Scre

enpr

intin

g

RF

sput

terin

gth

erm

al

evap

orat

ion

mic

rofa

bric

atio

n

5-50

0pp

mFa

stre

spon

sean

dre

cove

ry

times

ch

eap

Hig

hop

erat

ing

tem

pera

ture

s

suff

erfr

omsu

lphu

rpo

ison

ing

limite

dra

nge

ofco

atin

gs

Nag

leet

al

(199

8)

SAW

Piez

oele

ctric

ityPh

otol

ithog

raph

y

airb

rush

ing

scre

enpr

intin

g

dipc

oatin

gsp

inco

atin

g

1pg

to1

mg

ofva

pour

1pg

mas

s

chan

ge

DLfrac14

2pp

mfo

roc

tane

and

1pp

mN

O2

and

1pp

mH

2S

with

poly

mer

mem

bran

es

Div

erse

rang

eof

coat

ings

high

sens

itivi

ty

good

resp

onse

times

IC

inte

grat

able

Com

plex

inte

rfac

eci

rcui

try

diffi

cult

tore

prod

uce

Nag

leet

al

(199

8)

Alb

ert

and

Lew

in(2

000)

and

Penz

aet

al(

2001

a)

QCM

Piez

oele

ctric

ityM

icro

mac

hini

ng

spin

coat

ing

airb

rush

ing

inkj

etpr

intin

g

dipc

oatin

g

15

Hz

ppm

1

ngm

ass

chan

geD

iver

sera

nge

ofco

atin

gs

good

batc

hto

batc

h

repr

oduc

ibili

ty

Poor

sign

al-t

o-no

ise

ratio

com

plex

circ

uitr

y

Nag

leet

al

(199

8)an

d

Kim

and

Cho

i(2

002)

Optical

devices

Inte

nsity

spec

trum

Dip

coat

ing

Low

ppb

DL

(NH

3)frac14

1pp

mw

ith

poly

anili

neco

atin

g

Imm

une

toel

ectr

omag

netic

inte

rfer

ence

fa

stre

spon

se

times

ch

eap

light

wei

ght

Suff

erfr

omph

otob

leac

hing

com

plex

inte

rfac

eci

rcui

try

rest

ricte

dlig

htso

urce

s

Jin

etal

(2

001)

and

Nag

leet

al

(199

8)

MOSFET

Thre

shol

d

volta

ge

chan

ge

Mic

rofa

bric

atio

n

ther

mal

evap

orat

ion

28m

Vp

pmfo

rto

luen

e

DLfrac14

(am

ines

Su

lphi

des)frac14

01p

pm

Max

imum

resp

onse

frac1420

0m

V

espe

cial

lyfo

ram

ines

Smal

llo

wco

stse

nsor

sC

MO

S

inte

grat

ible

and

repr

oduc

ible

Bas

elin

edr

ift

need

cont

rolle

d

envi

ronm

ent

Cov

ingt

onet

al

(200

1)

and

Kal

man

etal

(20

00)

Notes

HV

PGndash

high

vapo

rpr

essu

rega

sLV

PGndash

low

vapo

rpr

essu

rega

sD

RR b

ndashre

lativ

edi

ffer

entia

lre

sist

ance

chan

ge



Sensor Review


195





2000)















































reviewed in Table V

Conclusions















References











Sensor Review


196






































Sensor Review


197
































Sensor Review


198






(Carey 1987)



























































(Walt et al 1998)







1998)












Sensor Review


191




















































(Kalman et al 2000)































Sensor Review


192

Table

VC

hara

cter

istic

sof

com

mer

cial

e-no

ses

Man

ufacturer

Sensor

type

No

of

sensors

Applications

Pattern

recognition

commen

ts

Web

sitereferen

ceuniversity

backg

round

Airsense

analysisGmbH

MO

S10

Food

eval

uatio

nfla

vour

and

frag

ranc

ete

stin

gA

NN

D

C

PCA

Lapt

op

ww

wa

irsen

sec

om

AlphaMOS-Multi

Organ

olepticSystem

s

CP

MO

S

QC

M

SAW

6-24

Ana

lysi

sof

food

type

squ

ality

cont

rolo

ffoo

dst

orag

efr

esh

fish

and

petr

oche

mic

alpr

oduc

ts

pack

agin

gev

alua

tion

anal

ysis

of

dairy

prod

ucts

al

coho

licbe

vera

ges

and

perf

umes

AN

N

DFA

PCA

Des

ktop

ww

wa

lpha

-mos

com

Applied

Sensor

IR

MO

S

MO

SFET

QC

M

22Id

entifi

catio

nof

purit

ypr

oces

san

dqu

ality

cont

rol

envi

ronm

enta

lan

alys

is

med

ical

diag

nosi

s

AN

N

PCA

Lapt

op

ww

wa

pplie

dsen

sorc

om

Uni

vers

ityof

Link

opin

gs

Swed

en

AromaS

canPLC

CP

32En

viro

nmen

tal

mon

itorin

gch

emic

alqu

ality

cont

rol

phar

mac

eutic

alpr

oduc

tev

alua

tion

AN

N

Des

ktop

Uni

vers

ityof

Man

ches

ter

Inst

itute

ofsc

ienc

ean

dte

chno

logy

UK

Array

Tech

QC

M8

Dia

gnos

ing

lung

canc

er

food

anal

ysis

Uni

vers

ityof

Rom

e

Bloodhoundsensors

CP

14Fo

odev

alua

tion

flavo

uran

dfr

agra

nce

test

ing

mic

robi

olog

y

envi

ronm

enta

lm

onito

ring

degr

adat

ion

dete

ctio

n

AN

N

CA

PC

A

DA

Lapt

op

Uni

vers

ityof

Leed

sU

K

Cyran

oScience

Inc

CP

32Fo

odqu

ality

ch

emic

alan

alys

is

fres

hnes

ssp

oila

ge

cont

amin

atio

nde

tect

ion

cons

iste

ncy

info

ods

and

beve

rage

s

PCA

Palm

top

ww

wc

yran

osci

ence

sco

m

Cal

iforn

iain

stitu

teof

Tech

nolo

gy

USA

MarconiApplied

Technologies

QC

M

CP

MO

SSA

W

8-28

AN

N

DA

PC

AU

nive

rsity

ofW

arw

ick

UK

ElectronicSe

nsorTechnology

Inc

GC

SA

W1

Food

and

beve

rage

qual

ity

bact

eria

iden

tifica

tion

expl

osiv

es

and

drug

dete

ctio

nen

viro

nmen

tal

mon

itorin

g

SPR

Des

ktop

ww

we

stca

lcom

Forschungszen

trum

Karlsruhe

MO

SSA

W40

8

Envi

ronm

enta

lpr

otec

tion

indu

stria

lpr

oces

sco

ntro

lai

r

mon

itorin

gin

text

ilem

ills

fire

alar

ms

Qua

lity

cont

rol

info

od

prod

uctio

nA

utom

otiv

eap

plic

atio

ns

PCA

ww

wf

zkd

eFZ

K2

engl

ish

HKR-Sen

sorsystemeGmbH

QC

M6

Food

and

beve

rage

sco

smet

ics

and

perf

umes

or

gani

c

mat

eria

ls

phar

mac

eutic

alin

dust

ry

AN

N

CA

DFA

PC

A

Des

ktop

ww

wh

kr-s

enso

rde

Tech

nica

lU

nive

rsity

ofM

unic

h

Ger

man

y

Illumina

FOndash

Life

scie

nces

fo

odpr

oces

sing

ag

ricul

ture

ch

emic

alde

tect

ion

AN

Nw

ww

illu

min

aco

mTu

fts

Uni

vers

ity

USA

(Con

tinue

d)



Sensor Review


193

Table

V

Man

ufacturer

Sensor

type

No

of

sensors

Applications

Pattern

recognition

commen

ts

Web

sitereferen

ceuniversity

backg

round

Lennartz

ElectronicGmbH

MO

SQ

CM

16-4

0Fo

odan

dbe

vera

gepr

oces

sing

per

fum

eoi

lsa

gric

ultu

ralo

dour

s

and

chem

ical

anal

ysis

pr

oces

sco

ntro

l

AN

N

PCA

Des

ktop

ww

wle

nnar

tz-e

lect

roni

cde

PDF_

docu

men

ts

Uni

vers

ityof

Tubi

ngen

Marconitechnologies

MastiffElectronic

System

sLtd

CP

16Sn

iffs

palm

sfo

rpe

rson

alid

entifi

catio

nw

ww

mas

tiffc

ouk

MicrosensorSystem

sSA

W2

Che

mic

alag

ent

dete

ctio

nch

emic

alw

arfa

re(C

W)

agen

tsan

d

toxi

cin

dust

rial

chem

ical

s(T

ICs)

anal

ysis

Palm

top

ww

wm

icro

sens

orsy

stem

sco

mp

df

hazm

atca

d

OligoSe

nse

CO

ndashA

utom

otiv

eap

plic

atio

nsf

ood

eval

uatio

npa

ckag

ing

eval

uatio

nht

tp

ww

wo

ligos

ense

be

RST

Rostock

Rau

m-fah

rtund

UmweltschatzGmbH

MO

SQ

CM

SAW

6-10

Early

reco

gniti

onof

fires

w

arni

ngin

the

even

tof

esca

peof

haza

rdou

ssu

bsta

nces

le

akde

tect

ion

wor

kpla

cem

onito

ring

AN

N

PCA

Des

ktop

Ant

wer

pU

nive

rsity

B

elgi

um

ww

wr

st-r

osto

ckd

e

Shim

adzu

Co

MO

S6

PCA

D

eskt

op

Diag-Nose

Dia

gnos

ing

tube

rcul

osis

bo

wel

canc

ers

infe

ctio

nsin

wou

nds

and

the

urin

ary

trac

t

ww

wn

ose-

netw

ork

org

Cra

nfiel

dU

nive

rsity

B

edfo

rdsh

ire

Engl

and

Notes

MO

Sndash

met

alox

ide

sem

icon

duct

orC

Pndash

cond

uctin

gpo

lym

erQ

CM

ndashqu

artz

crys

talm

onito

rSA

Wndash

surf

ace

acou

stic

wav

eIR

ndashin

fra

red

MO

SFET

ndashm

etal

oxid

ese

mic

ondu

ctor

field

effe

ct

tran

sist

orG

Cndash

gas

chro

mat

ogra

phy

FOndash

fibre

optic

CO

ndashco

nduc

tive

olig

omer

AN

Nndash

artifi

cial

neur

alne

twor

kD

Cndash

dist

ance

clas

sifie

rsP

CA

ndashpr

inci

ple

com

pone

ntan

alys

isD

FAndash

disc

rimin

ant

func

tion

anal

ysis

C

Andash

clus

ter

anal

ysis

D

Andash

disc

rimin

ant

anal

ysis



Sensor Review


194

Table

VI

Sum

mar

yof

the

prop

ertie

sof

each

sens

orty

pere

view

ed

Sensortype

Mea

surand

Fabrication

Exam



Advantages

Disad

vantages

Referen

ce

Polymer

composites

Con

duct

ivity

Scre

enpr

intin

g

spin

coat

ing

dipc

oatin

g

spra

yco

atin

g

mic

rofa

bric

atio

n

ppb

for

HV

PGpp

mfo

rLV

PG

1pe

rce

ntD

RR

bp

pm

DL

01-

5pp

m

Ope

rate

atro

omte

mpe

ratu

re

chea

pdi

vers

era

nge

of

coat

ings

Sens

itive

tote

mpe

ratu

rean

d

hum

idity

Mun

ozet

al

(199

9)

Gar

dner

and

Dye

r(19

97)

and

Rya

net

al

(199

9)

Intrinsically

conducting

polymers

Con

duct

ivity

Elec

troc

hem

ical

chem

ical

poly

mer

isat

ion

01-

100

ppm

Sens

itive

topo

lar

anal

ytes

chea

pgo

odre

spon

setim

es

oper

ate

atro

omte

mpe

ratu

re

Sens

itive

tote

mpe

ratu

rean

d

hum

idity

su

ffer

from

base

line

drift

Nag

leet

al

(199

8)

Metal

oxides

Con

duct

ivity

Scre

enpr

intin

g

RF

sput

terin

gth

erm

al

evap

orat

ion

mic

rofa

bric

atio

n

5-50

0pp

mFa

stre

spon

sean

dre

cove

ry

times

ch

eap

Hig

hop

erat

ing

tem

pera

ture

s

suff

erfr

omsu

lphu

rpo

ison

ing

limite

dra

nge

ofco

atin

gs

Nag

leet

al

(199

8)

SAW

Piez

oele

ctric

ityPh

otol

ithog

raph

y

airb

rush

ing

scre

enpr

intin

g

dipc

oatin

gsp

inco

atin

g

1pg

to1

mg

ofva

pour

1pg

mas

s

chan

ge

DLfrac14

2pp

mfo

roc

tane

and

1pp

mN

O2

and

1pp

mH

2S

with

poly

mer

mem

bran

es

Div

erse

rang

eof

coat

ings

high

sens

itivi

ty

good

resp

onse

times

IC

inte

grat

able

Com

plex

inte

rfac

eci

rcui

try

diffi

cult

tore

prod

uce

Nag

leet

al

(199

8)

Alb

ert

and

Lew

in(2

000)

and

Penz

aet

al(

2001

a)

QCM

Piez

oele

ctric

ityM

icro

mac

hini

ng

spin

coat

ing

airb

rush

ing

inkj

etpr

intin

g

dipc

oatin

g

15

Hz

ppm

1

ngm

ass

chan

geD

iver

sera

nge

ofco

atin

gs

good

batc

hto

batc

h

repr

oduc

ibili

ty

Poor

sign

al-t

o-no

ise

ratio

com

plex

circ

uitr

y

Nag

leet

al

(199

8)an

d

Kim

and

Cho

i(2

002)

Optical

devices

Inte

nsity

spec

trum

Dip

coat

ing

Low

ppb

DL

(NH

3)frac14

1pp

mw

ith

poly

anili

neco

atin

g

Imm

une

toel

ectr

omag

netic

inte

rfer

ence

fa

stre

spon

se

times

ch

eap

light

wei

ght

Suff

erfr

omph

otob

leac

hing

com

plex

inte

rfac

eci

rcui

try

rest

ricte

dlig

htso

urce

s

Jin

etal

(2

001)

and

Nag

leet

al

(199

8)

MOSFET

Thre

shol

d

volta

ge

chan

ge

Mic

rofa

bric

atio

n

ther

mal

evap

orat

ion

28m

Vp

pmfo

rto

luen

e

DLfrac14

(am

ines

Su

lphi

des)frac14

01p

pm

Max

imum

resp

onse

frac1420

0m

V

espe

cial

lyfo

ram

ines

Smal

llo

wco

stse

nsor

sC

MO

S

inte

grat

ible

and

repr

oduc

ible

Bas

elin

edr

ift

need

cont

rolle

d

envi

ronm

ent

Cov

ingt

onet

al

(200

1)

and

Kal

man

etal

(20

00)

Notes

HV

PGndash

high

vapo

rpr

essu

rega

sLV

PGndash

low

vapo

rpr

essu

rega

sD

RR b

ndashre

lativ

edi

ffer

entia

lre

sist

ance

chan

ge



Sensor Review


195





2000)















































reviewed in Table V

Conclusions















References











Sensor Review


196






































Sensor Review


197
































Sensor Review


198




















































(Kalman et al 2000)































Sensor Review


192

Table

VC

hara

cter

istic

sof

com

mer

cial

e-no

ses

Man

ufacturer

Sensor

type

No

of

sensors

Applications

Pattern

recognition

commen

ts

Web

sitereferen

ceuniversity

backg

round

Airsense

analysisGmbH

MO

S10

Food

eval

uatio

nfla

vour

and

frag

ranc

ete

stin

gA

NN

D

C

PCA

Lapt

op

ww

wa

irsen

sec

om

AlphaMOS-Multi

Organ

olepticSystem

s

CP

MO

S

QC

M

SAW

6-24

Ana

lysi

sof

food

type

squ

ality

cont

rolo

ffoo

dst

orag

efr

esh

fish

and

petr

oche

mic

alpr

oduc

ts

pack

agin

gev

alua

tion

anal

ysis

of

dairy

prod

ucts

al

coho

licbe

vera

ges

and

perf

umes

AN

N

DFA

PCA

Des

ktop

ww

wa

lpha

-mos

com

Applied

Sensor

IR

MO

S

MO

SFET

QC

M

22Id

entifi

catio

nof

purit

ypr

oces

san

dqu

ality

cont

rol

envi

ronm

enta

lan

alys

is

med

ical

diag

nosi

s

AN

N

PCA

Lapt

op

ww

wa

pplie

dsen

sorc

om

Uni

vers

ityof

Link

opin

gs

Swed

en

AromaS

canPLC

CP

32En

viro

nmen

tal

mon

itorin

gch

emic

alqu

ality

cont

rol

phar

mac

eutic

alpr

oduc

tev

alua

tion

AN

N

Des

ktop

Uni

vers

ityof

Man

ches

ter

Inst

itute

ofsc

ienc

ean

dte

chno

logy

UK

Array

Tech

QC

M8

Dia

gnos

ing

lung

canc

er

food

anal

ysis

Uni

vers

ityof

Rom

e

Bloodhoundsensors

CP

14Fo

odev

alua

tion

flavo

uran

dfr

agra

nce

test

ing

mic

robi

olog

y

envi

ronm

enta

lm

onito

ring

degr

adat

ion

dete

ctio

n

AN

N

CA

PC

A

DA

Lapt

op

Uni

vers

ityof

Leed

sU

K

Cyran

oScience

Inc

CP

32Fo

odqu

ality

ch

emic

alan

alys

is

fres

hnes

ssp

oila

ge

cont

amin

atio

nde

tect

ion

cons

iste

ncy

info

ods

and

beve

rage

s

PCA

Palm

top

ww

wc

yran

osci

ence

sco

m

Cal

iforn

iain

stitu

teof

Tech

nolo

gy

USA

MarconiApplied

Technologies

QC

M

CP

MO

SSA

W

8-28

AN

N

DA

PC

AU

nive

rsity

ofW

arw

ick

UK

ElectronicSe

nsorTechnology

Inc

GC

SA

W1

Food

and

beve

rage

qual

ity

bact

eria

iden

tifica

tion

expl

osiv

es

and

drug

dete

ctio

nen

viro

nmen

tal

mon

itorin

g

SPR

Des

ktop

ww

we

stca

lcom

Forschungszen

trum

Karlsruhe

MO

SSA

W40

8

Envi

ronm

enta

lpr

otec

tion

indu

stria

lpr

oces

sco

ntro

lai

r

mon

itorin

gin

text

ilem

ills

fire

alar

ms

Qua

lity

cont

rol

info

od

prod

uctio

nA

utom

otiv

eap

plic

atio

ns

PCA

ww

wf

zkd

eFZ

K2

engl

ish

HKR-Sen

sorsystemeGmbH

QC

M6

Food

and

beve

rage

sco

smet

ics

and

perf

umes

or

gani

c

mat

eria

ls

phar

mac

eutic

alin

dust

ry

AN

N

CA

DFA

PC

A

Des

ktop

ww

wh

kr-s

enso

rde

Tech

nica

lU

nive

rsity

ofM

unic

h

Ger

man

y

Illumina

FOndash

Life

scie

nces

fo

odpr

oces

sing

ag

ricul

ture

ch

emic

alde

tect

ion

AN

Nw

ww

illu

min

aco

mTu

fts

Uni

vers

ity

USA

(Con

tinue

d)



Sensor Review


193

Table

V

Man

ufacturer

Sensor

type

No

of

sensors

Applications

Pattern

recognition

commen

ts

Web

sitereferen

ceuniversity

backg

round

Lennartz

ElectronicGmbH

MO

SQ

CM

16-4

0Fo

odan

dbe

vera

gepr

oces

sing

per

fum

eoi

lsa

gric

ultu

ralo

dour

s

and

chem

ical

anal

ysis

pr

oces

sco

ntro

l

AN

N

PCA

Des

ktop

ww

wle

nnar

tz-e

lect

roni

cde

PDF_

docu

men

ts

Uni

vers

ityof

Tubi

ngen

Marconitechnologies

MastiffElectronic

System

sLtd

CP

16Sn

iffs

palm

sfo

rpe

rson

alid

entifi

catio

nw

ww

mas

tiffc

ouk

MicrosensorSystem

sSA

W2

Che

mic

alag

ent

dete

ctio

nch

emic

alw

arfa

re(C

W)

agen

tsan

d

toxi

cin

dust

rial

chem

ical

s(T

ICs)

anal

ysis

Palm

top

ww

wm

icro

sens

orsy

stem

sco

mp

df

hazm

atca

d

OligoSe

nse

CO

ndashA

utom

otiv

eap

plic

atio

nsf

ood

eval

uatio

npa

ckag

ing

eval

uatio

nht

tp

ww

wo

ligos

ense

be

RST

Rostock

Rau

m-fah

rtund

UmweltschatzGmbH

MO

SQ

CM

SAW

6-10

Early

reco

gniti

onof

fires

w

arni

ngin

the

even

tof

esca

peof

haza

rdou

ssu

bsta

nces

le

akde

tect

ion

wor

kpla

cem

onito

ring

AN

N

PCA

Des

ktop

Ant

wer

pU

nive

rsity

B

elgi

um

ww

wr

st-r

osto

ckd

e

Shim

adzu

Co

MO

S6

PCA

D

eskt

op

Diag-Nose

Dia

gnos

ing

tube

rcul

osis

bo

wel

canc

ers

infe

ctio

nsin

wou

nds

and

the

urin

ary

trac

t

ww

wn

ose-

netw

ork

org

Cra

nfiel

dU

nive

rsity

B

edfo

rdsh

ire

Engl

and

Notes

MO

Sndash

met

alox

ide

sem

icon

duct

orC

Pndash

cond

uctin

gpo

lym

erQ

CM

ndashqu

artz

crys

talm

onito

rSA

Wndash

surf

ace

acou

stic

wav

eIR

ndashin

fra

red

MO

SFET

ndashm

etal

oxid

ese

mic

ondu

ctor

field

effe

ct

tran

sist

orG

Cndash

gas

chro

mat

ogra

phy

FOndash

fibre

optic

CO

ndashco

nduc

tive

olig

omer

AN

Nndash

artifi

cial

neur

alne

twor

kD

Cndash

dist

ance

clas

sifie

rsP

CA

ndashpr

inci

ple

com

pone

ntan

alys

isD

FAndash

disc

rimin

ant

func

tion

anal

ysis

C

Andash

clus

ter

anal

ysis

D

Andash

disc

rimin

ant

anal

ysis



Sensor Review


194

Table

VI

Sum

mar

yof

the

prop

ertie

sof

each

sens

orty

pere

view

ed

Sensortype

Mea

surand

Fabrication

Exam



Advantages

Disad

vantages

Referen

ce

Polymer

composites

Con

duct

ivity

Scre

enpr

intin

g

spin

coat

ing

dipc

oatin

g

spra

yco

atin

g

mic

rofa

bric

atio

n

ppb

for

HV

PGpp

mfo

rLV

PG

1pe

rce

ntD

RR

bp

pm

DL

01-

5pp

m

Ope

rate

atro

omte

mpe

ratu

re

chea

pdi

vers

era

nge

of

coat

ings

Sens

itive

tote

mpe

ratu

rean

d

hum

idity

Mun

ozet

al

(199

9)

Gar

dner

and

Dye

r(19

97)

and

Rya

net

al

(199

9)

Intrinsically

conducting

polymers

Con

duct

ivity

Elec

troc

hem

ical

chem

ical

poly

mer

isat

ion

01-

100

ppm

Sens

itive

topo

lar

anal

ytes

chea

pgo

odre

spon

setim

es

oper

ate

atro

omte

mpe

ratu

re

Sens

itive

tote

mpe

ratu

rean

d

hum

idity

su

ffer

from

base

line

drift

Nag

leet

al

(199

8)

Metal

oxides

Con

duct

ivity

Scre

enpr

intin

g

RF

sput

terin

gth

erm

al

evap

orat

ion

mic

rofa

bric

atio

n

5-50

0pp

mFa

stre

spon

sean

dre

cove

ry

times

ch

eap

Hig

hop

erat

ing

tem

pera

ture

s

suff

erfr

omsu

lphu

rpo

ison

ing

limite

dra

nge

ofco

atin

gs

Nag

leet

al

(199

8)

SAW

Piez

oele

ctric

ityPh

otol

ithog

raph

y

airb

rush

ing

scre

enpr

intin

g

dipc

oatin

gsp

inco

atin

g

1pg

to1

mg

ofva

pour

1pg

mas

s

chan

ge

DLfrac14

2pp

mfo

roc

tane

and

1pp

mN

O2

and

1pp

mH

2S

with

poly

mer

mem

bran

es

Div

erse

rang

eof

coat

ings

high

sens

itivi

ty

good

resp

onse

times

IC

inte

grat

able

Com

plex

inte

rfac

eci

rcui

try

diffi

cult

tore

prod

uce

Nag

leet

al

(199

8)

Alb

ert

and

Lew

in(2

000)

and

Penz

aet

al(

2001

a)

QCM

Piez

oele

ctric

ityM

icro

mac

hini

ng

spin

coat

ing

airb

rush

ing

inkj

etpr

intin

g

dipc

oatin

g

15

Hz

ppm

1

ngm

ass

chan

geD

iver

sera

nge

ofco

atin

gs

good

batc

hto

batc

h

repr

oduc

ibili

ty

Poor

sign

al-t

o-no

ise

ratio

com

plex

circ

uitr

y

Nag

leet

al

(199

8)an

d

Kim

and

Cho

i(2

002)

Optical

devices

Inte

nsity

spec

trum

Dip

coat

ing

Low

ppb

DL

(NH

3)frac14

1pp

mw

ith

poly

anili

neco

atin

g

Imm

une

toel

ectr

omag

netic

inte

rfer

ence

fa

stre

spon

se

times

ch

eap

light

wei

ght

Suff

erfr

omph

otob

leac

hing

com

plex

inte

rfac

eci

rcui

try

rest

ricte

dlig

htso

urce

s

Jin

etal

(2

001)

and

Nag

leet

al

(199

8)

MOSFET

Thre

shol

d

volta

ge

chan

ge

Mic

rofa

bric

atio

n

ther

mal

evap

orat

ion

28m

Vp

pmfo

rto

luen

e

DLfrac14

(am

ines

Su

lphi

des)frac14

01p

pm

Max

imum

resp

onse

frac1420

0m

V

espe

cial

lyfo

ram

ines

Smal

llo

wco

stse

nsor

sC

MO

S

inte

grat

ible

and

repr

oduc

ible

Bas

elin

edr

ift

need

cont

rolle

d

envi

ronm

ent

Cov

ingt

onet

al

(200

1)

and

Kal

man

etal

(20

00)

Notes

HV

PGndash

high

vapo

rpr

essu

rega

sLV

PGndash

low

vapo

rpr

essu

rega

sD

RR b

ndashre

lativ

edi

ffer

entia

lre

sist

ance

chan

ge



Sensor Review


195





2000)















































reviewed in Table V

Conclusions















References











Sensor Review


196






































Sensor Review


197
































Sensor Review


198

Table

VC

hara

cter

istic

sof

com

mer

cial

e-no

ses

Man

ufacturer

Sensor

type

No

of

sensors

Applications

Pattern

recognition

commen

ts

Web

sitereferen

ceuniversity

backg

round

Airsense

analysisGmbH

MO

S10

Food

eval

uatio

nfla

vour

and

frag

ranc

ete

stin

gA

NN

D

C

PCA

Lapt

op

ww

wa

irsen

sec

om

AlphaMOS-Multi

Organ

olepticSystem

s

CP

MO

S

QC

M

SAW

6-24

Ana

lysi

sof

food

type

squ

ality

cont

rolo

ffoo

dst

orag

efr

esh

fish

and

petr

oche

mic

alpr

oduc

ts

pack

agin

gev

alua

tion

anal

ysis

of

dairy

prod

ucts

al

coho

licbe

vera

ges

and

perf

umes

AN

N

DFA

PCA

Des

ktop

ww

wa

lpha

-mos

com

Applied

Sensor

IR

MO

S

MO

SFET

QC

M

22Id

entifi

catio

nof

purit

ypr

oces

san

dqu

ality

cont

rol

envi

ronm

enta

lan

alys

is

med

ical

diag

nosi

s

AN

N

PCA

Lapt

op

ww

wa

pplie

dsen

sorc

om

Uni

vers

ityof

Link

opin

gs

Swed

en

AromaS

canPLC

CP

32En

viro

nmen

tal

mon

itorin

gch

emic

alqu

ality

cont

rol

phar

mac

eutic

alpr

oduc

tev

alua

tion

AN

N

Des

ktop

Uni

vers

ityof

Man

ches

ter

Inst

itute

ofsc

ienc

ean

dte

chno

logy

UK

Array

Tech

QC

M8

Dia

gnos

ing

lung

canc

er

food

anal

ysis

Uni

vers

ityof

Rom

e

Bloodhoundsensors

CP

14Fo

odev

alua

tion

flavo

uran

dfr

agra

nce

test

ing

mic

robi

olog

y

envi

ronm

enta

lm

onito

ring

degr

adat

ion

dete

ctio

n

AN

N

CA

PC

A

DA

Lapt

op

Uni

vers

ityof

Leed

sU

K

Cyran

oScience

Inc

CP

32Fo

odqu

ality

ch

emic

alan

alys

is

fres

hnes

ssp

oila

ge

cont

amin

atio

nde

tect

ion

cons

iste

ncy

info

ods

and

beve

rage

s

PCA

Palm

top

ww

wc

yran

osci

ence

sco

m

Cal

iforn

iain

stitu

teof

Tech

nolo

gy

USA

MarconiApplied

Technologies

QC

M

CP

MO

SSA

W

8-28

AN

N

DA

PC

AU

nive

rsity

ofW

arw

ick

UK

ElectronicSe

nsorTechnology

Inc

GC

SA

W1

Food

and

beve

rage

qual

ity

bact

eria

iden

tifica

tion

expl

osiv

es

and

drug

dete

ctio

nen

viro

nmen

tal

mon

itorin

g

SPR

Des

ktop

ww

we

stca

lcom

Forschungszen

trum

Karlsruhe

MO

SSA

W40

8

Envi

ronm

enta

lpr

otec

tion

indu

stria

lpr

oces

sco

ntro

lai

r

mon

itorin

gin

text

ilem

ills

fire

alar

ms

Qua

lity

cont

rol

info

od

prod

uctio

nA

utom

otiv

eap

plic

atio

ns

PCA

ww

wf

zkd

eFZ

K2

engl

ish

HKR-Sen

sorsystemeGmbH

QC

M6

Food

and

beve

rage

sco

smet

ics

and

perf

umes

or

gani

c

mat

eria

ls

phar

mac

eutic

alin

dust

ry

AN

N

CA

DFA

PC

A

Des

ktop

ww

wh

kr-s

enso

rde

Tech

nica

lU

nive

rsity

ofM

unic

h

Ger

man

y

Illumina

FOndash

Life

scie

nces

fo

odpr

oces

sing

ag

ricul

ture

ch

emic

alde

tect

ion

AN

Nw

ww

illu

min

aco

mTu

fts

Uni

vers

ity

USA

(Con

tinue

d)



Sensor Review


193

Table

V

Man

ufacturer

Sensor

type

No

of

sensors

Applications

Pattern

recognition

commen

ts

Web

sitereferen

ceuniversity

backg

round

Lennartz

ElectronicGmbH

MO

SQ

CM

16-4

0Fo

odan

dbe

vera

gepr

oces

sing

per

fum

eoi

lsa

gric

ultu

ralo

dour

s

and

chem

ical

anal

ysis

pr

oces

sco

ntro

l

AN

N

PCA

Des

ktop

ww

wle

nnar

tz-e

lect

roni

cde

PDF_

docu

men

ts

Uni

vers

ityof

Tubi

ngen

Marconitechnologies

MastiffElectronic

System

sLtd

CP

16Sn

iffs

palm

sfo

rpe

rson

alid

entifi

catio

nw

ww

mas

tiffc

ouk

MicrosensorSystem

sSA

W2

Che

mic

alag

ent

dete

ctio

nch

emic

alw

arfa

re(C

W)

agen

tsan

d

toxi

cin

dust

rial

chem

ical

s(T

ICs)

anal

ysis

Palm

top

ww

wm

icro

sens

orsy

stem

sco

mp

df

hazm

atca

d

OligoSe

nse

CO

ndashA

utom

otiv

eap

plic

atio

nsf

ood

eval

uatio

npa

ckag

ing

eval

uatio

nht

tp

ww

wo

ligos

ense

be

RST

Rostock

Rau

m-fah

rtund

UmweltschatzGmbH

MO

SQ

CM

SAW

6-10

Early

reco

gniti

onof

fires

w

arni

ngin

the

even

tof

esca

peof

haza

rdou

ssu

bsta

nces

le

akde

tect

ion

wor

kpla

cem

onito

ring

AN

N

PCA

Des

ktop

Ant

wer

pU

nive

rsity

B

elgi

um

ww

wr

st-r

osto

ckd

e

Shim

adzu

Co

MO

S6

PCA

D

eskt

op

Diag-Nose

Dia

gnos

ing

tube

rcul

osis

bo

wel

canc

ers

infe

ctio

nsin

wou

nds

and

the

urin

ary

trac

t

ww

wn

ose-

netw

ork

org

Cra

nfiel

dU

nive

rsity

B

edfo

rdsh

ire

Engl

and

Notes

MO

Sndash

met

alox

ide

sem

icon

duct

orC

Pndash

cond

uctin

gpo

lym

erQ

CM

ndashqu

artz

crys

talm

onito

rSA

Wndash

surf

ace

acou

stic

wav

eIR

ndashin

fra

red

MO

SFET

ndashm

etal

oxid

ese

mic

ondu

ctor

field

effe

ct

tran

sist

orG

Cndash

gas

chro

mat

ogra

phy

FOndash

fibre

optic

CO

ndashco

nduc

tive

olig

omer

AN

Nndash

artifi

cial

neur

alne

twor

kD

Cndash

dist

ance

clas

sifie

rsP

CA

ndashpr

inci

ple

com

pone

ntan

alys

isD

FAndash

disc

rimin

ant

func

tion

anal

ysis

C

Andash

clus

ter

anal

ysis

D

Andash

disc

rimin

ant

anal

ysis



Sensor Review


194

Table

VI

Sum

mar

yof

the

prop

ertie

sof

each

sens

orty

pere

view

ed

Sensortype

Mea

surand

Fabrication

Exam



Advantages

Disad

vantages

Referen

ce

Polymer

composites

Con

duct

ivity

Scre

enpr

intin

g

spin

coat

ing

dipc

oatin

g

spra

yco

atin

g

mic

rofa

bric

atio

n

ppb

for

HV

PGpp

mfo

rLV

PG

1pe

rce

ntD

RR

bp

pm

DL

01-

5pp

m

Ope

rate

atro

omte

mpe

ratu

re

chea

pdi

vers

era

nge

of

coat

ings

Sens

itive

tote

mpe

ratu

rean

d

hum

idity

Mun

ozet

al

(199

9)

Gar

dner

and

Dye

r(19

97)

and

Rya

net

al

(199

9)

Intrinsically

conducting

polymers

Con

duct

ivity

Elec

troc

hem

ical

chem

ical

poly

mer

isat

ion

01-

100

ppm

Sens

itive

topo

lar

anal

ytes

chea

pgo

odre

spon

setim

es

oper

ate

atro

omte

mpe

ratu

re

Sens

itive

tote

mpe

ratu

rean

d

hum

idity

su

ffer

from

base

line

drift

Nag

leet

al

(199

8)

Metal

oxides

Con

duct

ivity

Scre

enpr

intin

g

RF

sput

terin

gth

erm

al

evap

orat

ion

mic

rofa

bric

atio

n

5-50

0pp

mFa

stre

spon

sean

dre

cove

ry

times

ch

eap

Hig

hop

erat

ing

tem

pera

ture

s

suff

erfr

omsu

lphu

rpo

ison

ing

limite

dra

nge

ofco

atin

gs

Nag

leet

al

(199

8)

SAW

Piez

oele

ctric

ityPh

otol

ithog

raph

y

airb

rush

ing

scre

enpr

intin

g

dipc

oatin

gsp

inco

atin

g

1pg

to1

mg

ofva

pour

1pg

mas

s

chan

ge

DLfrac14

2pp

mfo

roc

tane

and

1pp

mN

O2

and

1pp

mH

2S

with

poly

mer

mem

bran

es

Div

erse

rang

eof

coat

ings

high

sens

itivi

ty

good

resp

onse

times

IC

inte

grat

able

Com

plex

inte

rfac

eci

rcui

try

diffi

cult

tore

prod

uce

Nag

leet

al

(199

8)

Alb

ert

and

Lew

in(2

000)

and

Penz

aet

al(

2001

a)

QCM

Piez

oele

ctric

ityM

icro

mac

hini

ng

spin

coat

ing

airb

rush

ing

inkj

etpr

intin

g

dipc

oatin

g

15

Hz

ppm

1

ngm

ass

chan

geD

iver

sera

nge

ofco

atin

gs

good

batc

hto

batc

h

repr

oduc

ibili

ty

Poor

sign

al-t

o-no

ise

ratio

com

plex

circ

uitr

y

Nag

leet

al

(199

8)an

d

Kim

and

Cho

i(2

002)

Optical

devices

Inte

nsity

spec

trum

Dip

coat

ing

Low

ppb

DL

(NH

3)frac14

1pp

mw

ith

poly

anili

neco

atin

g

Imm

une

toel

ectr

omag

netic

inte

rfer

ence

fa

stre

spon

se

times

ch

eap

light

wei

ght

Suff

erfr

omph

otob

leac

hing

com

plex

inte

rfac

eci

rcui

try

rest

ricte

dlig

htso

urce

s

Jin

etal

(2

001)

and

Nag

leet

al

(199

8)

MOSFET

Thre

shol

d

volta

ge

chan

ge

Mic

rofa

bric

atio

n

ther

mal

evap

orat

ion

28m

Vp

pmfo

rto

luen

e

DLfrac14

(am

ines

Su

lphi

des)frac14

01p

pm

Max

imum

resp

onse

frac1420

0m

V

espe

cial

lyfo

ram

ines

Smal

llo

wco

stse

nsor

sC

MO

S

inte

grat

ible

and

repr

oduc

ible

Bas

elin

edr

ift

need

cont

rolle

d

envi

ronm

ent

Cov

ingt

onet

al

(200

1)

and

Kal

man

etal

(20

00)

Notes

HV

PGndash

high

vapo

rpr

essu

rega

sLV

PGndash

low

vapo

rpr

essu

rega

sD

RR b

ndashre

lativ

edi

ffer

entia

lre

sist

ance

chan

ge



Sensor Review


195





2000)















































reviewed in Table V

Conclusions















References











Sensor Review


196






































Sensor Review


197
































Sensor Review


198

Table

V

Man

ufacturer

Sensor

type

No

of

sensors

Applications

Pattern

recognition

commen

ts

Web

sitereferen

ceuniversity

backg

round

Lennartz

ElectronicGmbH

MO

SQ

CM

16-4

0Fo

odan

dbe

vera

gepr

oces

sing

per

fum

eoi

lsa

gric

ultu

ralo

dour

s

and

chem

ical

anal

ysis

pr

oces

sco

ntro

l

AN

N

PCA

Des

ktop

ww

wle

nnar

tz-e

lect

roni

cde

PDF_

docu

men

ts

Uni

vers

ityof

Tubi

ngen

Marconitechnologies

MastiffElectronic

System

sLtd

CP

16Sn

iffs

palm

sfo

rpe

rson

alid

entifi

catio

nw

ww

mas

tiffc

ouk

MicrosensorSystem

sSA

W2

Che

mic

alag

ent

dete

ctio

nch

emic

alw

arfa

re(C

W)

agen

tsan

d

toxi

cin

dust

rial

chem

ical

s(T

ICs)

anal

ysis

Palm

top

ww

wm

icro

sens

orsy

stem

sco

mp

df

hazm

atca

d

OligoSe

nse

CO

ndashA

utom

otiv

eap

plic

atio

nsf

ood

eval

uatio

npa

ckag

ing

eval

uatio

nht

tp

ww

wo

ligos

ense

be

RST

Rostock

Rau

m-fah

rtund

UmweltschatzGmbH

MO

SQ

CM

SAW

6-10

Early

reco

gniti

onof

fires

w

arni

ngin

the

even

tof

esca

peof

haza

rdou

ssu

bsta

nces

le

akde

tect

ion

wor

kpla

cem

onito

ring

AN

N

PCA

Des

ktop

Ant

wer

pU

nive

rsity

B

elgi

um

ww

wr

st-r

osto

ckd

e

Shim

adzu

Co

MO

S6

PCA

D

eskt

op

Diag-Nose

Dia

gnos

ing

tube

rcul

osis

bo

wel

canc

ers

infe

ctio

nsin

wou

nds

and

the

urin

ary

trac

t

ww

wn

ose-

netw

ork

org

Cra

nfiel

dU

nive

rsity

B

edfo

rdsh

ire

Engl

and

Notes

MO

Sndash

met

alox

ide

sem

icon

duct

orC

Pndash

cond

uctin

gpo

lym

erQ

CM

ndashqu

artz

crys

talm

onito

rSA

Wndash

surf

ace

acou

stic

wav

eIR

ndashin

fra

red

MO

SFET

ndashm

etal

oxid

ese

mic

ondu

ctor

field

effe

ct

tran

sist

orG

Cndash

gas

chro

mat

ogra

phy

FOndash

fibre

optic

CO

ndashco

nduc

tive

olig

omer

AN

Nndash

artifi

cial

neur

alne

twor

kD

Cndash

dist

ance

clas

sifie

rsP

CA

ndashpr

inci

ple

com

pone

ntan

alys

isD

FAndash

disc

rimin

ant

func

tion

anal

ysis

C

Andash

clus

ter

anal

ysis

D

Andash

disc

rimin

ant

anal

ysis



Sensor Review


194

Table

VI

Sum

mar

yof

the

prop

ertie

sof

each

sens

orty

pere

view

ed

Sensortype

Mea

surand

Fabrication

Exam



Advantages

Disad

vantages

Referen

ce

Polymer

composites

Con

duct

ivity

Scre

enpr

intin

g

spin

coat

ing

dipc

oatin

g

spra

yco

atin

g

mic

rofa

bric

atio

n

ppb

for

HV

PGpp

mfo

rLV

PG

1pe

rce

ntD

RR

bp

pm

DL

01-

5pp

m

Ope

rate

atro

omte

mpe

ratu

re

chea

pdi

vers

era

nge

of

coat

ings

Sens

itive

tote

mpe

ratu

rean

d

hum

idity

Mun

ozet

al

(199

9)

Gar

dner

and

Dye

r(19

97)

and

Rya

net

al

(199

9)

Intrinsically

conducting

polymers

Con

duct

ivity

Elec

troc

hem

ical

chem

ical

poly

mer

isat

ion

01-

100

ppm

Sens

itive

topo

lar

anal

ytes

chea

pgo

odre

spon

setim

es

oper

ate

atro

omte

mpe

ratu

re

Sens

itive

tote

mpe

ratu

rean

d

hum

idity

su

ffer

from

base

line

drift

Nag

leet

al

(199

8)

Metal

oxides

Con

duct

ivity

Scre

enpr

intin

g

RF

sput

terin

gth

erm

al

evap

orat

ion

mic

rofa

bric

atio

n

5-50

0pp

mFa

stre

spon

sean

dre

cove

ry

times

ch

eap

Hig

hop

erat

ing

tem

pera

ture

s

suff

erfr

omsu

lphu

rpo

ison

ing

limite

dra

nge

ofco

atin

gs

Nag

leet

al

(199

8)

SAW

Piez

oele

ctric

ityPh

otol

ithog

raph

y

airb

rush

ing

scre

enpr

intin

g

dipc

oatin

gsp

inco

atin

g

1pg

to1

mg

ofva

pour

1pg

mas

s

chan

ge

DLfrac14

2pp

mfo

roc

tane

and

1pp

mN

O2

and

1pp

mH

2S

with

poly

mer

mem

bran

es

Div

erse

rang

eof

coat

ings

high

sens

itivi

ty

good

resp

onse

times

IC

inte

grat

able

Com

plex

inte

rfac

eci

rcui

try

diffi

cult

tore

prod

uce

Nag

leet

al

(199

8)

Alb

ert

and

Lew

in(2

000)

and

Penz

aet

al(

2001

a)

QCM

Piez

oele

ctric

ityM

icro

mac

hini

ng

spin

coat

ing

airb

rush

ing

inkj

etpr

intin

g

dipc

oatin

g

15

Hz

ppm

1

ngm

ass

chan

geD

iver

sera

nge

ofco

atin

gs

good

batc

hto

batc

h

repr

oduc

ibili

ty

Poor

sign

al-t

o-no

ise

ratio

com

plex

circ

uitr

y

Nag

leet

al

(199

8)an

d

Kim

and

Cho

i(2

002)

Optical

devices

Inte

nsity

spec

trum

Dip

coat

ing

Low

ppb

DL

(NH

3)frac14

1pp

mw

ith

poly

anili

neco

atin

g

Imm

une

toel

ectr

omag

netic

inte

rfer

ence

fa

stre

spon

se

times

ch

eap

light

wei

ght

Suff

erfr

omph

otob

leac

hing

com

plex

inte

rfac

eci

rcui

try

rest

ricte

dlig

htso

urce

s

Jin

etal

(2

001)

and

Nag

leet

al

(199

8)

MOSFET

Thre

shol

d

volta

ge

chan

ge

Mic

rofa

bric

atio

n

ther

mal

evap

orat

ion

28m

Vp

pmfo

rto

luen

e

DLfrac14

(am

ines

Su

lphi

des)frac14

01p

pm

Max

imum

resp

onse

frac1420

0m

V

espe

cial

lyfo

ram

ines

Smal

llo

wco

stse

nsor

sC

MO

S

inte

grat

ible

and

repr

oduc

ible

Bas

elin

edr

ift

need

cont

rolle

d

envi

ronm

ent

Cov

ingt

onet

al

(200

1)

and

Kal

man

etal

(20

00)

Notes

HV

PGndash

high

vapo

rpr

essu

rega

sLV

PGndash

low

vapo

rpr

essu

rega

sD

RR b

ndashre

lativ

edi

ffer

entia

lre

sist

ance

chan

ge



Sensor Review


195





2000)















































reviewed in Table V

Conclusions















References











Sensor Review


196






































Sensor Review


197
































Sensor Review


198

Table

VI

Sum

mar

yof

the

prop

ertie

sof

each

sens

orty

pere

view

ed

Sensortype

Mea

surand

Fabrication

Exam



Advantages

Disad

vantages

Referen

ce

Polymer

composites

Con

duct

ivity

Scre

enpr

intin

g

spin

coat

ing

dipc

oatin

g

spra

yco

atin

g

mic

rofa

bric

atio

n

ppb

for

HV

PGpp

mfo

rLV

PG

1pe

rce

ntD

RR

bp

pm

DL

01-

5pp

m

Ope

rate

atro

omte

mpe

ratu

re

chea

pdi

vers

era

nge

of

coat

ings

Sens

itive

tote

mpe

ratu

rean

d

hum

idity

Mun

ozet

al

(199

9)

Gar

dner

and

Dye

r(19

97)

and

Rya

net

al

(199

9)

Intrinsically

conducting

polymers

Con

duct

ivity

Elec

troc

hem

ical

chem

ical

poly

mer

isat

ion

01-

100

ppm

Sens

itive

topo

lar

anal

ytes

chea

pgo

odre

spon

setim

es

oper

ate

atro

omte

mpe

ratu

re

Sens

itive

tote

mpe

ratu

rean

d

hum

idity

su

ffer

from

base

line

drift

Nag

leet

al

(199

8)

Metal

oxides

Con

duct

ivity

Scre

enpr

intin

g

RF

sput

terin

gth

erm

al

evap

orat

ion

mic

rofa

bric

atio

n

5-50

0pp

mFa

stre

spon

sean

dre

cove

ry

times

ch

eap

Hig

hop

erat

ing

tem

pera

ture

s

suff

erfr

omsu

lphu

rpo

ison

ing

limite

dra

nge

ofco

atin

gs

Nag

leet

al

(199

8)

SAW

Piez

oele

ctric

ityPh

otol

ithog

raph

y

airb

rush

ing

scre

enpr

intin

g

dipc

oatin

gsp

inco

atin

g

1pg

to1

mg

ofva

pour

1pg

mas

s

chan

ge

DLfrac14

2pp

mfo

roc

tane

and

1pp

mN

O2

and

1pp

mH

2S

with

poly

mer

mem

bran

es

Div

erse

rang

eof

coat

ings

high

sens

itivi

ty

good

resp

onse

times

IC

inte

grat

able

Com

plex

inte

rfac

eci

rcui

try

diffi

cult

tore

prod

uce

Nag

leet

al

(199

8)

Alb

ert

and

Lew

in(2

000)

and

Penz

aet

al(

2001

a)

QCM

Piez

oele

ctric

ityM

icro

mac

hini

ng

spin

coat

ing

airb

rush

ing

inkj

etpr

intin

g

dipc

oatin

g

15

Hz

ppm

1

ngm

ass

chan

geD

iver

sera

nge

ofco

atin

gs

good

batc

hto

batc

h

repr

oduc

ibili

ty

Poor

sign

al-t

o-no

ise

ratio

com

plex

circ

uitr

y

Nag

leet

al

(199

8)an

d

Kim

and

Cho

i(2

002)

Optical

devices

Inte

nsity

spec

trum

Dip

coat

ing

Low

ppb

DL

(NH

3)frac14

1pp

mw

ith

poly

anili

neco

atin

g

Imm

une

toel

ectr

omag

netic

inte

rfer

ence

fa

stre

spon

se

times

ch

eap

light

wei

ght

Suff

erfr

omph

otob

leac

hing

com

plex

inte

rfac

eci

rcui

try

rest

ricte

dlig

htso

urce

s

Jin

etal

(2

001)

and

Nag

leet

al

(199

8)

MOSFET

Thre

shol

d

volta

ge

chan

ge

Mic

rofa

bric

atio

n

ther

mal

evap

orat

ion

28m

Vp

pmfo

rto

luen

e

DLfrac14

(am

ines

Su

lphi

des)frac14

01p

pm

Max

imum

resp

onse

frac1420

0m

V

espe

cial

lyfo

ram

ines

Smal

llo

wco

stse

nsor

sC

MO

S

inte

grat

ible

and

repr

oduc

ible

Bas

elin

edr

ift

need

cont

rolle

d

envi

ronm

ent

Cov

ingt

onet

al

(200

1)

and

Kal

man

etal

(20

00)

Notes

HV

PGndash

high

vapo

rpr

essu

rega

sLV

PGndash

low

vapo

rpr

essu

rega

sD

RR b

ndashre

lativ

edi

ffer

entia

lre

sist

ance

chan

ge



Sensor Review


195





2000)















































reviewed in Table V

Conclusions















References











Sensor Review


196






































Sensor Review


197
































Sensor Review


198





2000)















































reviewed in Table V

Conclusions















References











Sensor Review


196






































Sensor Review


197
































Sensor Review


198






































Sensor Review


197
































Sensor Review


198
































Sensor Review


198

a review of gas sensors employed in electronic nose applications

Documents

analytica chimica acta

intrinsically conducting polymers

general response times

electronic nose applications

cent carbon black

gas sensors employed

pca desktop ann

surface acoustic wave