New Strategies for Environmental Water Analysis

Bin HuDepartment of Chemistry, Wuhan University,

Wuhan 430072, China

2009.03.03

Outline► Introduction

► Microextraction techniques combined with atomic spectrometry for trace/ultratrace elements analysis in environmental water

► Microextraction combined with chromatographic techniques for environmental water analysis

► Conclusion

The nature water cycle Water covers 70% of the earth's surface and is vital to all living things. Water is always circulating between the earth's surface and the atmosphere in the water cycle.

To well serve sustainable development strategy of utilizing and protecting water resource, it is very important to monitor the quantity of environmental water.

However, water quality monitoring is a difficult task, as the scope of water analysis is inherently broad, encompassing analytical studies involving organic and inorganic contaminants.

Introduction

Environmental Water AnalysisFor studies of inorganic contaminants in water samples, trace elements analysis and elemental speciation protocols for elements such as As, Cr, Hg, Sb, Se and Sn have been receiving considerable attention.

As for organic pollutants, they encompass a diverse group of compounds, including pharmaceuticals, drugs of abuse, personal-care products (PCPs), steroids and hormones, surfactants, perfluorinated compounds (PFCs), flame retardants, industrial additives and agents, and gasoline additives, as well as their transformation products (TPs).

The development of simple, inexpensive, sensitive and rapid analytical methodologies for the quantitative analysis of inorganic contaminants, organic pollutants, their metabolites, and their TPs in environmental waters is very mandatory.

Inorganic contaminants◆Atomic absorption spectrometry► Flame atomic absorption spectrometry (FAAS)► Graphite furnace atomic absorption spectrometry (GFAAS)

◆Atomic emission spectrometry► Inductively coupled plasma optical emission spectrometry (ICP-OES)► Microwave induced plasma optical emission spectrometry (MIP-OES)► Direct current plasma optical emission spectrometry (DCP-OES)► Glow discharge optical emission spectrometry (GD-OES)

◆ Atomic fluorescence spectrometry (AFS)◆ Atomic mass spectrometry► Inductively coupled plasma mass spectrometry (ICP-MS)► Microwave plasma mass spectrometry (MW-MS)► Glow discharge mass spectrometry (GD-MS)◆ Electrochemical methods

Instrumental Methods for Water Analysis

Organic pollutants

◆ Chromatography► Gas chromatography (GC)► high performance liquid chromatography (HPLC)► Super-critical fluid chromatography (SFC)► Electrophoresis

◆ Molecular spectroscopy► Ultraviolet –visible spectrophotometry (UV-VIS)► Fluorescence spectrometry ► Chemiluminescence……

◆ Mass spectrometry

◆……

Instrumental Methods for Water Analysis

Hyphenated Techniques for Elemental Speciation

• The most powerful and effective approach for the elemental speciation.

• These involve the coupling a selective separation with sensitive and element-specific detection.

• For increased quality control, molecule-selective detection can be coupled to separation device.

Why Sample Pretreatment?

Powerful instruments The purpose of sample pretreatment:The purpose of sample pretreatment:

●● Removal of coexisting interferencesRemoval of coexisting interferences●● Preconcentration of the target analytesPreconcentration of the target analytes

Problems：► Very low concentration of analytes► Analyte species highly dependent on time and

space► Complicated matrix, severe matrix effect

One of the key step to the whole analytical procedure

Sample pretreatment

Why Microextraction?

◆Convention methods for sample pretreatment

►high reproducibility, easy to use

► requiring large amount of high-purity organicsolvents

► easily contamination

► prone to be analyte loss

► time-consuming

The development of faster, simpler, inexpensive and more environmentally friendly sample-preparation techniques is an important issue in analytical chemistry

Trends for sample pretreatment

Solventless and Environmental benign

MiniaturizationMiniaturizationVery small amount of Very small amount of sample available sample available

Solid phase extraction (SPE)Solid phase microextraction

(SPME)Liquid phase microextraction

(LPME)Stir bar sorptive extraction

(SBSE)Supercritical fluid extraction

(SFE)……

SPMELPME

SPME, LPME and SBSE are the most attractive ones

Single drop microextraction (SDME)

Sampling modes: direct and head space

LPME Hollow fiber liquid phase microextaction (HF-LPME)

◆LPME is a environmental benign sample preparation techniques

◆High preconcentration factors

◆ Since LPME was first proposed by Liu and his colleagues in 1996,it was accepted immediately by the analytical community. More and more papers was published in different scientific journals in recent years

Liquid Phase Microextraction

Dispersive liquid phase microextraction (DLPME)

MALDI-TOFMSESI-MS (MS)

ICP-IDMS

Schematic representation of direct single-drop microextraction system

Schematic representation of head space single-drop microextraction system

SDME

Popular apparatus

ICP-AESICP-MS

ICP-IDMS

Technical set-up for LPME based on U-shaped fiber

Technical set-up for LPME based on fiber

Membrane based LPME

Dispersive liquid phase microextraction

Sample solution

Extraction solvent，dispersive solvent

Chelating reagentCloudy solution

Organic phase with small volume

Clear aqueous solution

Centrifugation

Detection

Capillary Microextraction

◆CME is a environmental benign sample preparation techniques

◆ CME integrates a number of sample handling operations such as extraction, preconcentration, and sample introduction for instrumental analysis that follows the sample preparation step

◆ Like solid-phase microextraction (SPME), CME is also a simple, inexpensive, easy-to-automate, portable, and time-efficient sample preparation technique

ICP-AESICP-MS

R. Eisert, J. Pawliszyn, Anal. Chem., 1997, 69, 3140H. Kataoka, J. Pawliszyn, Anal. Chem., 1999, 71, 4237

On-line CME-HPLC

On-line CME-ICP-MS

Simple

Rapid

Less sample required

Solvent-free

automation

ICP-AESICP-MS

ICP-IDMS

Extraction materials for CMEGC capillary commercially availableGC capillary commercially availablePPY Coated CapillaryPPY Coated CapillarySolSol--gel Coated Capillarygel Coated Capillary

Capillary packed with stainless steel wire Capillary packed with stainless steel wire or fiber /PEEKor fiber /PEEK tubetubeParticle packed capillary /PEEKParticle packed capillary /PEEK tube (MIP, tube (MIP, AlkylAlkyl--diol silica)diol silica)

C18 silica monolithic capillaryC18 silica monolithic capillary

Polymer monolithic capillaryPolymer monolithic capillary

Coated capillaryCoated capillary

Packing materialsPacking materials

Monolithic materialsMonolithic materials

◆ Sol-gel CME, as a viable solventless or little solvent extraction technique, was first introduced in 2002 by Bigham and workers. More and more papers was published in different scientific journals in recent years

◆Most applications of CME were focused on the organic analysis, very few reports on its application in inorganic analysis

Extraction Mode

1.Cap；2.Vial；3.Sample； 4.PDMS stir bar；5.Stir

Text

Text

Text

Text

Direct Headspace

Stir bar sorptive extraction (SBSE) is derived from solid-phase microextraction (SPME), which was developed by Baltussen et al in 1999

The amount of sorbent in the stir bar is higher than the amount in the SPME fiber, so better reproducibility and higher sensitivity and recoveryare expected

Stir Bar Sorptive Extraction

Microextraction Techniques Combined with Atomic

Spectrometry for Trace/ultratrace Elements Analysis in Environmental Water

MALDI-TOFMSESI-MS (MS)

ICP-IDMS

Microextraction Techniques

Combined with Electrothermal

Vaporization-ICP-MS for

Trace/ultratrace Elements Analysis

Electrothermal Vaporization (ETV)One of the versatile sample introduction techniques currently employed in plasma optical emission spectrometry and mass spectrometry.

low sample consumption (μL or mg)high transport efficiency (~80%)low absolute detection limit (fg)the ability to directly analyze both liquid and solid samples.

◆ High sensitivity◆ Good precision◆ Simultaneous multielemental analysis◆ Isotopic information◆ A dynamic range exceeding five orders of magnitude

The Features of ICP-MS for Elemental Analysis

The ways to improve the analytical performance of ETV-ICP-MS

◆ The best set-up of ETV device

◆ The employment of chemical modifier

◆ Combined with separation /preconcentration techniques

Microextraction: miniaturized sample pretreatment technique

LPME/CME/SBSE-ETV-ICP-MS----a perfect coupling for inorganic analysis

ETV: micro amount sample introduction technique

System for Single Drop Microextraction

Single drop microextraction (SDME)-ETV-ICP-MS for the determination of Be, Co, Pd, and Cd

L. B. Xia, B. Hu, Z. C. Jiang, Y. L. Wu, Y. Liang, Anal. Chem., 76(2004)2910-2915.

Benzoylacetone (BZA)

can chelate with Be, Co,

Pd, and Cd to form

thermally stable and

volatile complexes.

BZA was used both as

the extractant and

chemical modifier.

SDME parametersAqueous volume, 1 mL; benzene drop volume, 4 μL; extraction time, 10 min; flow rate: 0.2 mL/min.

(A) 20 pg Be with 0.1 μmol BZA as chemical modifier vaporized at 900 oC. (A’) The residual signal of empty firing at 2500 oC.(B) 20 pg Co with 0.1 μmol BZA as chemical modifier vaporized at 900 oC.(B’) The residual signal of empty firing at 2500 oC.

ETV signal profiles

Analytical performance

Analytical applications

ICP-AESICP-MS

MALDI-TOFMSESI-MS (MS)

ICP-IDMS

Speciation of Inorganic Selenium

L. B. Xia, B. Hu, J. Anal. At. Spectrom., 21(2006)362-365.

Extraction:Extractant, ammonium pyrrolidine dithiocarbamate (APDC)/CCl4;aqueous volume, 2.5 mL; pH, 5.0; stirring, 800 rpm; extraction time, 20 min.

Basis: The Se(IV)-PDC chelate could be extracted by CCl4 under the pH range of 4-6.2, and Se(VI) remains in aqueous phase. The sum of selenite and selenate was determined after prereduction of selenate to selenite by gentle boiling in 5 M HCl mediums for 50 min

The schematic of experimental set-up for HF-LPME

Hollow fiber liquid phase microextraction (HF-LPME)-ETV-ICP-MS for trace analysis

CE –HPLC –

GC –

ICP-AESICP-MS

ICP-IDMS

Analytical performance of two modes of LPME

Species Detection limit Actual enrichment factor RSD (%)

Instrument(ng/mL)

Methoda

(pg/mL)Methodb

(pg/mL) Methoda Methodb Methoda Methodb

Selenite 0.20 0.50 2.7 410 75 7.1 13.2

Selenate 0.23 0.56 3.0 410 75 7.6 13.9

(a) HF-LPME-ETV-ICP-MS. (b) SDME-ETV-ICP-MS.

Sample Selenite +Selenate Selenite Selenate Total Se by

PN-ICP-MS

East lake water 1.35±0.09 1.12±0.08 0.23±0.03 1.39±0.03

Pool water 0.90±0.07 0.79±0.05 0.11±0.02 0.92±0.03

Yangtze river water 0.70±0.08 0.62±0.06 0.08±0.01 0.72±0.03

Analytical results (mean±s d, n=3) for selenite and selenate in real water samples (ng/mL)

Sample

Speciation of Vanadium

CDTAMasking V(IV)

APDC HF-LPME

ETV-ICP-OESV(V)

APDC

HF-LPME

ETV-ICP-OES

Total V

V(IV)＝Total V-V(V)

L. Li, B. Hu, L. B. Xia, Z. C. Jiang, Talanta, 70(2007)468-473.

HF-LPME Setup

200 400 600 800 1000 1200 1400 1600 1800 200010

15

20

25

30

35

40

45

1700 oC

Si

gnal

inte

nsity

(pea

k he

ight

)

Temperature (oC)

Effect of Vaporization Temperature

0 200 400 600 800 1000 1200

20

40

60

80

100

270 OC

Wei

ght %

Temperature/ OC

TG Curve of V-APDC Chelate

APDC Chemical Modification

Signal profileETV parameters

Drying: 100oC，ramp 10s, hold 15s

Vaporization: 1700oC, hold 6s

Cleaning: 2500oC, hold 3s

HF-LPME Conditions

2 3 4 5 60

10

20

30

40

50

Sign

al in

tens

ity (p

eak

heig

ht)

pH of sample

V-APDC V(IV)-CDTA

Solvent: CCl4

pH: 5.0Extraction time: 8 min APDC: 6.0×10-3 mol/L CDTA: 5.0×10-5 mol/L

LOD: 86 pg/mL for V(IV); 71 pg/mL for V(V)RSD: 5.3% (C＝2.0 ng/mL, n=7)Enrichment factor: 74Linear range: 0.75～75 ng/mL, r2>0.99

Merits of Figures

Environmental WatersVanadium (IV) Vanadium (V)

Sample Added (ng mL-1)

Found (ng mL-1)

Recovery (%)

Added (ng mL-1)

Found (ng mL-1)

Recovery (%)

0 N.D. a 0 4.20 ± 0.26 3.96 ± 0.11 b

Lake water

5 5.15 ± 0.23 103 5 8.93 ± 0.46 98

0 N.D. a 0 2.41 ± 0.19 2.27 ± 0.13 b

Tap water

5 4.93 ± 0.18 99 5 7.52 ± 0.40 103

0 N.D. a 0 2.80 ± 0.11 Sea water

5 4.71 ± 0.22 94 5 8.35 ± 0.56 107

a not detected. b total concentration of vanadium determined by ICP-MS.

Ref. Analytes/Sample

FeaturesExtraction Analytical Performance

1 Cd, Pb/Fresh water, human serum

8-Hydroxyquinoline/Chloroform SDME

LOD(pg mL-1): Cd 4.6, Pb 2.9; EF: Cd 140, Pb 190

2 Al species/natural waters and

drinks

8-Hydroxyquinoline/chloroform SDME

LOD(pg mL-1): Al 3.3; EF: 210

3 Co, Hg, Pb/Lake water, serum,

hair

PAN/ [C4MIM][PF6] SDME

LOD(pg mL-1): Co 5.5, Hg 6.4, Pb 11.3; EF: Co 350, Hg 50, Pb

60

4 La PMBP/benzene SDME LOD(pg mL-1): La 16; EF: 500

5 Cu, Zn, Pd, Cd, Hg, Pb, Bi/Peach leaves

sea water

DDTC/CCl4 HF-LPME LOD(pg mL-1): 1.6(Bi)-28.7(Zn); EF: 20(Hg)-305(Cu)

LPME-ETV-ICP-OES/MS for Trace Analysis. A Survey

1. L. Li, B. Hu, L. B. Xia, Z. C. Jiang, Talanta, 70(2007)468-473.2. L. B. Xia, B. Hu, Z. C. Jiang, Y. L. Wu, L. Li, R. Chen, J. Anal. At. Spectrom., 20(2005)441-446.3. L. B. Xia, X. Li, Y. L. Wu, B. Hu, R. Chen, Spectrochim. Acta, 63B(2008)1290-1296.4. 吴英亮，江祖成，胡斌，高等学校化学学报，24(2003)1793-1794. 5. L. B. Xia, Y. L. Wu, B. Hu, J. Mass Spectrom., 42(2007)803-810.

CE –HPLC –

GC –

ICP-AESICP-MS

MALDI-TOFMSESI-MS (MS)

ICP-IDMS

(i) The method provided much larger enrichment factor and thus a much lower detection limit

(ii) Chelating reagent could be used both as extracting reagent and as chemical modifier, and analytes could be vaporized and transported as gaseous chelates into the ICP, therefore, improved the analytical sensitivity

(iii) LPME technique combined with a micro-amount detection technique was proved to be a perfect coupling and 100% of sample after pretreatment could be introduced into the ICP for detection

Summary

CE –HPLC –

GC –

ICP-AESICP-MS

MALDI-TOFMSESI-MS (MS)

ICP-IDMS

LPME Combined with GFAAS for trace Elements Analysis

Similar to ETV-ICP-MS, LPME is also very suitable for combination with GFAAS for trace elements and their speciation by selection of appropriate extraction system

Ref. Analytes/Sample

FeaturesExtraction Analytical Performance

1 Cd, Pb/ Environmental

water

dithizone/toluene SDME LOD(pg mL-1): Cd 2.0, Pb 90; EF: Cd 118, Pb 90

2 As(III), As(V)/Environmental

waters and human hair extracts

APDC/toluene HF-LPME LOD(pg mL-1): As 120; EF: 78

3 MeHg+/Hair extracts, sludges

toluene/thiourea HF-LLLME

LOD(pg mL-1): MeHg+ 100, EF: 204

4 Co, Ni/Environmental

water, rice

PAN/CCl4-acetone DLPME

LOD(pg mL-1):Co 21, Ni 33; EF: Co 101; Ni 200

LPME-GFAAS for Trace Analysis. A Survey

1. H. M. Jiang, B. Hu, Microchim. Acta, 2008, in press.2. H. M. Jiang, B. Hu, B. B. Chen, Anal. Chim. Acta, accepted.3. H. M. Jiang, B. Hu, B. B. Chen, W. Q. Zu, Spectrochim. Acta, 63B(2008)770-776.4. H. M. Jiang, B. Hu, B. B. Chen, W. Q. Zu, Spectrochim. Acta, 63B(2008)770-776.

6 μm silica skeletons

8 μm

25 nm

LOD：1.6 ng L-1

Preconcentration factor：436RSD：6.2% Simple, rapid, sensitive, high tolerance for the interference

Monolithic Capillary Microextraction-ETV-ICP-MS for Al Speciation

Fei Zheng, Bin Hu, Spectrochim. Acta Part B, 63(2008)9-18.

Analytical results of Al fractionation (mean ± s.d., n = 3) in rainwater and fruit juice

Sample pH aAlT / μg L-1 All / μg L-1 Alo / μg L-1bAll fraction

(%)

Rainwater1

Rainwater2

Rainwater3

Tomato juice

Cucumber juice

Watermelon juice

5.46

5.38

5.62

4.24

5.21

5.33

3.23 ± 0.15

2.94 ± 0.20

3.76 ± 0.18

6.21 ± 0.21

18.56 ± 0.74

33.29 ± 1.77

2.60 ± 0.08

2.01 ± 0.08

3.27 ± 0.16

4.71 ± 0.13

12.89 ± 0.84

15.33 ± 0.78

0.63 ± 0.02

0.93 ± 0.04

0.49 ± 0.03

1.50 ± 0.07

5.67 ± 0.38

17.96 ± 0.89

80.5 ± 2.5

68.4 ± 2.7

87.0 ± 4.3

75.8 ± 2.1

69.5 ± 4.5

46.0 ± 2.3

a All : labile monomeric Al; Alo: non-labile monomeric Al; AlT: total monomeric Alb The percentage of labile monomeric Al in total monomeric Al of real samples

Sample introduction system from the graphite adsorption bar to the ETV and the ETV-ICPconnecting interface

Graphite bar micro-extraction device

Zirconia-coated graphite adsorption bar

Xuli Pu, Bin Hu*, et al., J. Mass Spectrom., 41(2006)887-893.

Sample introduction system from the graphite adsorption bar to the ETV and the ETV-ICPconnecting interface

Analytical performance

Analytical application

ICP-AESICP-MS

MALDI-TOFMSESI-MS (MS)

ICP-IDMS

Capillary Microextraction on-line Hyphenated with ICP-MS for Trace

Elements Analysis

Simultaneous speciation of inorganic As(III)/As(V) and Cr(III)/Cr(VI) in natural waters utilizing ordered mesoporous Al2O3 CME-ICP-MS

Wenling Hu, Fei Zheng, Bin Hu, et al., J. Hazedous. Mater., 151(2008)58-64.

Sample loading

Elution/eluent introduction

Scanning electron microscopic images of (A) enlarged surface view of hostile capillary, (B) enlarged surface view of ordered mesoporous Al2O3coated capillary.

A B

TEM micrographes of (C) ordered mesoporous Al2O3coating, magnification: 50,000 ×(D) non-mesoporous Al2O3 coating,magnification: 30,000 ×

C D

Effect of pH on the adsorption rate (%) of As(V), As(III), Cr(VI) and Cr(III)

Capillary: 40 cm × 320 µm i.d.Separation pH: pH 4.0Sample flow rate: 0.1 mL min-1

Eluent: 0.1 mL of 0.01mol l-1 NaOH at flow rate of 0.1 mL min-1

Separation conditions

Detection limits : 0.7 and 18 ng L-1 for As(V) and Cr(VI), and 3.4 and 74 ng L-1 for As(III) and Cr(III)

Enrichment factor: 5

RSDs: 3.1, 4.0, 2.8 and 3.9 % (C= 1 ng mL−1, n = 7) for As(V), As(III), Cr(VI) and Cr(III).

SEM for MPTS-silica monolithic capillary

SEM for AAPTS-silica monolithic capillary

600× 2400×

On-line dual silica monolithic CME-ICP-MS for sequential determination of inorganic arsenic and selenium species

1 2 3 4 5 6 7 8 90

20

40

60

80

100

Abso

rptio

n pe

rcen

tage

(%)

pH

As(III) Se(IV) As(V) Se(VI)

0 1 2 3 4 5 6 7 8 9 100

20

40

60

80

100

Adso

rptio

n pe

rcen

tage

(%)

pH

As(V) Se(VI) As(III) Se(IV)

Effect of pH

3-mercaptopropyltrimethoxysilane (MPTS)

AAPTS

Fei Zheng, Bin Hu, J. Anal. At. Spectrom., submitted. N-(2-aminoethyl)-3-aminopropyltrimethoxysilane

(AAPTS)

MPTS-silica monolithic capillary (-SH)As(III)/Se(IV) retained was eluted with 100 μL of 0.2 mol L-1 HNO3-3% thiourea (m/v)

AAPTS-silica monolithic capillary (-NH2)As(V)/Se(VI) retained was eluted with 100 μL of 0.5 mol L-1 HNO3

On-line dual silica monolithic CME-ICP-MS

SpeciesLinear range

(µg L-1)Linear equations

Linear coefficient

(R2)

R.S.D(C=1 μg L-1,

n=7)

Detectionlimits

(ng L-1)

Enrichmentfactor

As(III)Se(IV)As(V)Se(VI)

0.05-160.1-160.05-160.05-16

y = 80130x-2993y = 13706x-2759y = 84416x+422y = 14246x+5975

0.99830.99470.99780.9924

4.3%3.3%5.8%6.5%

10.931.16.211.6

34.337.536.139.0

Analytical performance of on-line dual-column CME-ICP-MS

Samples Element Certified(μg L-1)

Determined(μg L-1)

t-Testc

GSB Z50004-88

GBS Z50027-94

Total AsAs(III)As(V)

Total SeSe(IV)Se(VI)

59.3 ± 4.2--

23.8 ± 2.7--

54.0 ± 5.4a

3.4 ± 0.250.6 ± 5.225.3 ± 1.4b

3.3 ± 0.122.0 ± 1.4

1.701.86

a This total As is the sum of As(III) and As(V) determined through on-line dual silica monolithic CME-ICP-MS system; b This total Se is the sum of Se(IV) and Se(VI) determined through on-line dual silica monolithic CME-ICP-MS system; c t0.05,2 = 4.30

Analytical results of As(V), As(III), Se(IV) and Se(VI) in CRM environmental water (mean ± s.d., n=3)

CE –HPLC –

GC –

ICP-AESICP-MS

MALDI-TOFMSESI-MS (MS)

ICP-IDMS

Microextraction Combined with

Chromatographic Techniques

for Environmental Water

Analysis

CE –HPLC –

GC –

ICP-AESICP-MS

MALDI-TOFMSESI-MS (MS)

ICP-IDMS

Determination of organophosphorus pesticide residues using SDME-GC-FPD

Q. Xiao, B. Hu, Talanta, 41(2006)887-893.

The factors affecting the extraction efficiencyOrganic drop volume: 1.5 µL toluene Extraction time: 20 minStirring rate: 600 rpm Sample pH: pH 5-6 (natural pH for waters)Salt concentration: No salt addition Extraction temperature: Room temperature

Analytes A B R2 Enrichment factors

LODs(ng/ml)

dichlorvos -0.02824 0.10859 0.99949 23 0.58phorate -0.04029 0.40819 0.99993 97 0.22fenitrothion 0.00332 0.45375 0.99984 109 0.35malathion 0.03596 0.30824 0.99967 99 0.26parathion 0.02198 0.39791 0.99976 99 0.21quinalphos 0.02985 0.35295 0.99953 97 0.37

Analytical Performance

OPPs Added/ng·ml-1

Found/ ng·ml-1

Recovery/% RSD/%

dichlorvos 25

1.974.62

98.692.4

0.72.4

phorate 25

1.815.32

90.7106.5

8.52.7

fenitrothion 25

1.814.94

90.898.9

5.43.3

malathion 25

1.824.89

91.497.7

4.62.7

parathion 25

1.834.84

91.796.9

6.12.7

quinalphos 25

1.914.97

95.599.4

6.80.6

Six OPPs recoveries in East Lake water samples

Fruit juice analysis: No OPPs was detected in pear juice, organge juice and apple juice. The recoveries for all spiked fruit juice samples(analysed after dilution) were between 77.7% and 113.6% with an RSD of less than 13.4.

HS-SDME Coupled with GC-ICP-MS for Butyltin Compounds Speciation

GC-ICP-MS

Schematic of experimental set-up of HS-SDME

4.0 4.5 5.0 5.5 6.0 6.5 7.0

0

250000

500000

750000

1000000

1250000

1500000

1750000

Sign

al in

tens

ity

Time (min)

STD solution

PACS-2 sediment

MBT

TPrT(I.S.)

DBT TBT

Chromatograms for sample

Q. Xiao, B. Hu, M. He, J. Chromatogr. A, 1211(2008)135-141.

NaBEt4derivatization HS-SDMESolvent: 2.0 µL decane; 0.5%NaBEt4: 20 µL; pH: 5; stirring: 600 rpm, 5 min

NaBH4derivatization HS-SDMESolvent: 2.0 µL decane; 3%NaBEt4: 0.2 mL; pH: 3; stirring: 600 rpm, 5 min

Analytical performance data by HS-SDME-GC-ICP-MS

Comparison of detection limits for butyltins

Analysis of butyltins in seawater sample ( n = 3)

Determination of butyltins in PACS-2 sediment (mean±s.d., n=3)

Analysis of butyltins in shellfish samples ( n = 3)

Chemical structures of PBDEs

HF-LPME-GC-ICP-MS for the Analysis of Polybrominated Diphenyl Ethers

Qin Xiao, Bin Hu, et al., J. Am. Soc. Mass Spectrom., 18(2007)1740-1748.

Microextraction conditionsExtraction solvent: decane 30% methanol was added to avoid the adsorption of apolar compounds on the glass walls Stirring rate: 1000 rpmExtraction time: 20 minExtraction temperature: 40 oCIon strength: no salt addition

Monitoring isotope79Br and 81Br

Analyte Enrichment factors of HF-LPME

BDE28 83

BDE47 54

BDE100 37.5

BDE99 30.5

Enrichment factors

AnalyteLinearity/

ng/mL R Detection Limit/ ng/L RSD/%

BDE28 0.2-20 0.9999 15.2 6.8BDE47 0.2-20 0.9999 32.8 5.1

BDE100 0.2-20 0.9999 24.5 9.1

BDE99 0.2-20 0.9990 40.5 8.3

Analytical performance

Real sampleSample

preparationaExtraction

timeDetection technique

Injection volume

LODs Ref.

human serum,water, soil, and

dust

HF-LPME 20 min GC-ICP-MS 1 μL 15.2-40.5 ng/L This work

sewage sludge LLE 18 h GC-ICP-MS 2 μL 90-200b ng/L [22]

water samples HF-MMLLE 60 min GC-MS 2 μL 0.3-1.1 ng/L [20]

water samples SBSE 25 h GC-MS - 0.3-7.8 ng/L [9]

food samples SPE-HPLC fractionation

- GC-MS-MS 4 μL 80-680 ng/L [30]

water samples HS-SPME 30 min GC-MS-MS - 0.02-0.06 ng/L [8]

solid samples HS-SPME 60 min GC-MS-MS - 5.4-109 pg/g [31-32]

sediments MAE 24 min GC-ITMS 70 μL 4-20 pg/g [33]

birds SPE - GC-MS - 0.1 and 0.4 ng/g [34]

a: HF-LPME, hollow fibre liquid phase microextraction; LLE, liquid liquid extraction; HF-MMLLE, hollow-fiber microporous membrane liquid–liquid extraction; SBSE, stir bar sorptive extraction; SPE, solid phase extraction; HS-SPME: headspace-solid phase microextraction; MAE, microwave-assisted extraction.b: instrument detection limits.

Comparison of the methods for the determination of PBDEs

COLLEGE OF CHEMISTRY AND MOLECULAR SCIENCES, WUHAN UNIV.

HF-LPME-GC-ICP-MS chromatograms for soil (a), dust (b), water (c) and serum (e)

• Soil, dust, water and serum

0 2 4 6 8 10 12

0

50000

100000

150000

200000

Sign

al in

tens

ity (C

PS)

Time (min)

BDE28

BDE47

BDE100

BDE99I. S.

abcdefg

a: Soilb: Dustc: East Lake waterd: East Lake water spiked 1 ng/mLe: Human serum (10-fold dilution)f: Human serum spiked 10 ng/mL (10-fold dilution)g: Human serum spiked 50 ng/mL (50-fold dilution)

HS-SDME-HPLC for Polycyclic Aromatic Hydrocarbons (PAHs)

HS-SDME conditions

Extraction solvent: 10 μL saturated β-cyclodextrin solution; pH: 5.0

Addition salt: 0.2 g/mL NaCl; Temperature: 40oC

Extraction time: 10 min; Stirring speed: 1000 rpm

Y. L. Wu, L. B. Xia, R. Chen, B. Hu, Talanta, 74(2008)470-477.

PAH Instrument(ng/mL)

Method(ng/mL)

Actualenrichment factor

RSD (%) DLR

nap 6.0 0.097 30 6.1 0.3-50

phe 3.8 0.016 53 7.1 0.05-5

ant 1.5 0.004 18 5.6 0.01-1.25flu 28.0 0.247 50 6.7 0.7-50Pyr 11.6 0.098 20 6.1 0.3-50

Analytical performance

Determination of PAHs in waters

Inclusion precedure

β-cyclodextrin

3 4 5 6 7 8 9 10 11 12

23

24

25

26

27

28

29

30pyr

flu

ant

phe

nap

fluor

esce

nce

inte

nsity

/LU

time/min

with ß-CD without ß-CD

•Extract PAHs effectively by forming inclusion complex•Enhance the fluorescence intensity in HPLC analysis

β-cyclodextrin

PAHs Added (ng/mL) Determined (ng/mL) Recovery (%)

NAP

0 0.71 -

2 2.88±0.05 108.5±5.1

5 5.68±0.17 99.4±8.1

10 10.83±0.09 101.2±2.1

PHE

0 0.38 -

0.2 0.57±0.01 95±5.1

0.5 0.89±0.02 102±6.5

1 1.35±0.04 97±8.5

ANT

0 0.08 -

0.05 0.127±0.002 94±4.7

0.125 0.217±0.006 109.6±8.0

0.25 0.332±0.008 100.8±6.9

FLU

0 n.d.a -

2 2.21±0.05 110.5±6.5

5 5.23±0.11 104.6±6.1

10 10.34±0.24 103.4±6.7

PYR

0 0.33 -

2 2.48±0.06 107.5±7.0

5 5.48±0.09 103±4.8

10 10.35±0.25 100.2±7.0

Analytical results of PAHs in real water sample (Mean±sd, n=3)

CE –HPLC –

GC –

ICP-AESICP-MS

MALDI-TOFMSESI-MS (MS)

ICP-IDMS

LLLME-HPLC-UV for Organomercury

CE –HPLC –

GC –

ICP-AESICP-MS

MALDI-TOFMSESI-MS (MS)

ICP-IDMSSpecies LOD Actual enrichment factor (fold)

RSD (%) method (n=7)

Equation Correlation coefficient

Linearity (ng mL-1)

Instrument (µg mL-1)

Method (ng mL-1)

MeHg 0.45 3.8 120 8.9 y=0.9+0.05857x 0.9920 5-100

EtHg 0.15 0.7 215 6.4 y=0.6+0.155x 0.9862 1-100

PhHg 0.10 0.29 350 6.6 y=-3.7+0.39143x 0.9976 1-100

Analytical performance for the analysis of organomercury by LLLME-HPLC

LLLME-HPLC-UV for Organomercury

L. B. Xia, Y. L. Wu, B. Hu, J. Chromatogr. A, 1173(2007)44-51.

SampleSpecies

East lake water Synthetic water sample

Added (ng/mL)

5 10 20 5 10 20

Determined MeHg 5.92±0.56 10.88±1.02 20.86±1.33 4.90±0.52 10.11±0.88 20.09±1.22

EtHg 4.98±0.43 10.09±0.65 19.88±1.07 5.03±0.49 9.92±0.54 20.13±0.98

PhHg 5.02±0.43 9.97±0.63 19.90±1.01 4.98±0.45 9.97±0.55 19.88±1.03

Analytical results of water samples (mean±sd, n=3)

CE –HPLC –

GC –

ICP-AESICP-MS MALDI-TOFMS

ESI-MS (MS)

ICP-IDMS

Methylmercury (as Hg) in DORM-2 was found to be 4.42±0.41 μg g−1, which was in good agreement with the certified value (4.47± 0.32 μg g−1) for methylmercury.

Certified reference material

Standard mixture

HPLC mobile phase, 70% methanol, 30% 0.02M NaAc-Ac, (PH6.0, containing 0.1 mM 2-mercaptoethanol), 0.01M Na2S2O3

Organic solvent:Toluene

Stirring speed: 1500 rpm

Extraction time: 20 min

Acceptor:0.05M Na2S2O3

LLLME parameters

Headspace single drop and hollow fiber liquid phase microextractions for HPLC determination of phenols

HS-SDMEDonor phase: 0.05 mol L-1 HNO3 Acceptor phase: 0.05 mol L-1 NaOHMicrodrop volume: 10 µL Sample-to-headspace volume ratio: 3:1Extraction temperature: 70 oCStirring rate: 1000 rpmExtraction time: 15 minSalt addition: 0.25 g mL-1 NaCl

HS-HF-LPMEDonor phase: 0.05 mol L-1 HNO3 Acceptor phase: 0.05 mol L-1 NaOHMicrodrop volume: 10 µL Sample-to-headspace volume ratio: 1:1Extraction temperature: 60 oCStirring rate: 900 rpmExtraction time: 20 minSalt addition: 0.25 g mL-1 NaCl

Experimental set-up for HS-HF-LPME

Y. L. Wu, B. Hu, Y. L. Hou, J. Sep. Sci., published online.

Analytical performance data for phenols

Analytes Linearity range

Correlationcoefficient

(r2)

Limits of detection

(LODs, ng mL-1)

Enrichment factor

RSD (%)(n=7)

HS-SDME

Ph 10-1000 0.9944 2.1 15.8 3.7

CP 1-500 0.9981 0.2 198.9 4.0

DCP 5-500 0.9979 0.8 159.7 9.8

TCP 5-500 0.9935 1.1 194.8 6.7

HS-HF-LPME

Ph 10-1000 0.9962 4.2 9.2 6.3

CP 5-500 0.9980 0.4 149.9 3.6

DCP 5-500 0.9989 0.4 301.9 3.1

TCP 5-500 0.9996 0.4 411.1 4.8

Honey and three real environmental water samples including East Lake water, Yangtz River water, and tap water were analyzed and no target analytes in honey and all the three water samples were detected. The content of phenol (Ph) in toner obtained by HS-SDME-HPLC-UV and HS-HF-LPME- HPLC-UV was found to be 2.92 ±0.19 and 2.76 ± 0.24 µg g -1, respectively.

Chromatograms of HS-HF-LPME-HPLC-UV and HS-SDME-HPLC-UV for the toner sample and spiked toner sample

Ph

CP

DCPTCP

HS-HF-LPME-HPLC-UV for toner

HS-SDME-HPLC-UV for toner

HS-HF-LPME-HPLC-UV for spiked toner

HS-SDME-HPLC-UV for spiked toner

◆ Since there was no direct contact with the sample matrix, both HS-SDME and HS-HF-LPME were performed without interference.

◆ HS-SDME is simpler than HS-HF- LPME, while HS-HF-LPME is more robust than HS-SDME and can tolerate a relatively higher stirring rate.

◆ Compared to HS-SDME, HS-HF-LPME has larger specific extraction interface that makes the volatile compounds especially the less volatile compounds reach the equilibrium in a short time.

◆ Either HS-SDME or HS-HF-LPME combined with HPLC-UV has been demonstrated to be an effective method for the analysis phenols in real world samples with different matrix.

Summary

CE –HPLC –

GC –

ICP-AESICP-MS

MALDI-TOFMSESI-MS (MS)

ICP-IDMS

(i) Three microextraction techniques, LPME, CME and SBSE, are faster, simpler, inexpensive and more environmentally friendlysample-preparation techniques;

(ii) The device of LPME is quite simple, and no sample carry-overassociated with it, but its reproducibility should be improved;

(iii) The volume and surface area of the extraction phase for SBSE are larger than those of CME, thus, a better reproducibility and higher sensitivity than CME are expected when SBSE is used.

(iv) Compared with LPME, SBSE is more robust;(v) Several unsolved problems associated with CME and SBSE,

such as the physical damage of the coating, limited SBSE coatings available;

(vi) Microextraction techniques combined with different detection methods are simple and robust, suitable for the implementation of trace metals (including speciation) and organic pollutants analysis in routine protocols for environmental water.

Conclusions

Acknowledgments

◆ National Nature Science Foundation of China

◆ Excellent Young Scientist Foundation of Hubei Province

◆ NCET, MOE of China

◆ Wuhan Municipal Science & Technology Committee

Thank you for your attention!