trace metal analysis in sediments using aas and asv techniques

Awad Albalwi Student No:3343297

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Chemical Lab Report

Trace Metal Analysis in Sediments Using AAS and ASV Techniques

Procedure- AAS- 4samples (Port Kembla 2) sediments were obtained and their masses recorded. In addition 4 samples of

blank were prepared. they were then placed into polyethylene digestion vessels. 10ml of conc HNO3 was

added to each tube . in addition 1 ml spike was added to 1blank(1) and 1sample(1) tubes and 2ml spike was

added to anther 1blank(2) and 1 sample(2), the tubes were then heated on the hot plate for 15 minutes.

After 15 minutes the tubes were removed from the hot plate and hydrogen peroxide was added dropwise to

each vessel (approx 1 ml H2O2), the tubes were then placed back on the hot plate for 10 minutes. This was

repeated 4 times until all organic materials were eliminated via oxidation to volatile oxides. Digests were

then removed from the heating block and each solution filtered into 100ml volumetric flasks and made up to

mark with Milli-q water.

Combined standards were then prepared in the range from 0-10mg/L from stock solutions as

explained in lab book. Unknown was collected in 100ml volumetric flask and made up to the mark with Milli-q

water. Sediments samples were all diluted by a factor of 10 into 100ml volumetric flasks to bring analytes

into optimum concentration range for analysis.

The absorbance and concentration of each analyte was then recorded on the AAS instrument. The

wavelengths used for each analyte is shown in the table below.

Metal Wavelength (nm)

Pb 217

Zn 213.7

Cu 324.8

Cd 228.8

ASV- combined standard solution by appropriate dilution. All sediment solutions were then diluted as per

calculations in pre lab. Unknown solutions were then diluted by a factor of 100. All final solutions were made

up in 10% electrolyte solution.

A blank run was performed using 10% electrolyte solution to optimize parameters of instrument. 40μl

each individual stock solution was subsequently added and an analysis performed after each addition to

determine which peaks belong to which analytes. 10ml of unknown solution was then pipetted into ASV flask

and then analyzed by ASV. 3 x 40μL standard additions of combined standard solutions were then added and

new analysis was performed after each addition. This process was then repeated for all diluted sediment

solutions. Peak Areas where recorded and calibration curves generated allowing the concentration of

analytes in the solutions to be determined. Instrument parameters used for the analysis are shown below.

Parameters

Deposition E (mV) -1300

Initial potential E (mV) -1200

Final potential (mV) -100

Deposition time (s) 60

Step E (mV) 6

Pulse Width (ms) 40

Pulse period (ms) 100

Pulse Amplitude(mV) 50


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Results- The results obtained by both methods are shown in the tables below. Discussion of the results

and errors in the results is provided in the discussion section.

AAS results

Table1. summary of an analysis Pb in spike un spike blank ,sediment samples & unknown lead ABS Conc (ppm) Amount

of Pb in 100ml (mg)

Weight of the sample (g)

Pb in the sample (mg/g)

Mg/Kg Sx Sx*3.18 Interval Confidence

Blank (1)spike 0.19245 10.0 10.0

0.29 0.94

10±0.9

Blank (2)spike 0.19365 10.1 10.1

0.29 0.94

10±0.9

Sediment(1) 0.07745 3.9 3.9 0.5002 0.777 779.4 0.23 0.76 3.9±0.8

Sediment(2) 0.07715 3.9 3.9 0.5003 0.776 776.0 0.23 0.76 3.9±0.8

Sediment(1) spike 0.22765 11.9 11.9

0.5011

2.378 2378. 0.32 1.04

12±1

Sediment(2)spike 0.32715 17.2 17.2

0.5003

3.443 3443.9 0.43 1.39

17±1

Unknown (Awad) 0.08625 4.4

0.24 0.76

4.4±0.8

Table2. summary of an analysis Cu in spike un spike blank ,sediment samples & unknown

Copper ABS Conc (ppm)

Amount of cu in 100ml (mg)


Cu in the sample (mg/g)

Mg/Kg Sx Sx*2.78

Interval Confidence

Blank (1)spike 1.0105 11.8 10.0 0.410 1.14 12±1

Blank (2)spike 2.0105 23.7 10.1 0.727 2.02 24±2

Sidment(1) 0.5987 6.9 3.9 0.5002 1.375 1375.9 0.321 0.89 6.9±0.9

Sidment(2) 0.6003 6.9 3.9 0.5003 1.379 1379.4 0.321 0.89 6.9±0.9

Sidment(1) spiKe 1.1286 13.2 11.9

0.5011 2.634 2634. 0.442 1.23 13±1

Sidment(2)spike 2.4485 28.9 17.2 0.5003 5.7849 5783. 0.882 2.45 29±2

Unknown -awad) 0.3612 4.1

0.297 0.83 4.1±0.8

Table3. summary of an analysis Pb in spike un spike blank ,sediment samples & unknown

Cadimum ABS Conc

(ppm) Amount of cd in 100ml (mg)


Cd in the sample (mg/g)


Blank (1)spike 0.2915 1.248 0.1248 0.485 1.35 1±1

Blank (2)spike 0.524 2.605 0.2605 0.500 1.39 3±1

Sidment(1) 0.0009 -0.448 -0.0448 0.5002 -0.0896 -89.64 0.525 1.46 -0.4±1

Sidment(2) 0.001 -0.448 -0.0448 0.5003 -0.0895 -89.51 0.525 1.46 -0.4±1

Sidment(1) spiKe 0.2749 1.151 0.1151

0.5011 0.2297 229.7 0.486 1.35 1±1

Sidment(2)spike 0.4797 2.347 0.2347 0.5003 0.4691 469.05 0.494 1.37 2±1

Unknown 0.3484 1.580 0.485 1.35 2±1


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Table4. summary of an analysis Pb in spike un spike blank ,sediment samples & unknown

Zinc ABS Conc

(ppm) Amount of zn in 100ml (mg)


Zn in the sample (mg/g)


Blank (1)spike 1.175 11.068 1.107 1.59 4.43 11±4

Blank (2)spike 2.09 20.255 2.025 2.90 8.05 20±8

Sidment(1) 1.279 12.112 1.211 0.5002 2.421 2421.38 1.73 4.82 12±5

Sidment(2) 1.293 12.252 1.225 0.5003 2.448 2449.00 1.75 4.88 12±5

Sidment(1) spiKe 1.411 13.437 1.344 0.5011 2.681 2681.53 1.92 5.33 13±5

Sidment(2)spike 1.22 11.519 1.152 0.5003 2.302 2302.49 1.65 4.60 12±5

Unknown (Awad) 0.1387 0.7 0.69 1.92 0.7±2

Table5.extarction efficiency of spike sample.

Spike Recoveries Cd % Cu % Pb % Zn %

Blank (1)+ 1ml (spike) 17.0 118. 102.8 117.6

Blank (2) + 2ml(spike) 15.3 121. 51.7 105.

Sedment(1)+ 1ml(spike) 156 63. 160.4 26.5

Sedment(2) + 2ml(spike) 139.7 110.2 133.5 n/a

Table6. comaring beween Reference&sedment results

Metal Reference mg/kg Sediment (1) mg/Kg % accuracy LOD (mg) Sensitivity

Zn 2000 2421.38 80% 0.61

0.018

Cu 1230 1375.9 88.3% 1.7

0.0996

Cd <1 -89.64 n/a 11.75

0.083

Pb 670 779.4 83.7% 0.014

0.171

Fig(1a)

Fig(1b)

Fig(2a)

Fig(2b)


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ASV results Table.7 measurements of concentration heavy elements of sediment(1)&unknown from ASV method.

Sample Type [Cd] (mg/L) [Cu] (mg/L) [Pb] (mg/L) [Zn] (mg/L)

Unknown 0.55 2.3 2.9 n/a

[Cd] (mg/l) [Cu] (mg/ L) [Pb] (mg/l) [Zn] (mg/l)

Reference n/a n/a n/a n/a

Sample 0.35 1.72 3.005 n/a

Fig(3a) Fig(3b)

Fig(4a)

Fig(4b)


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Discussion/Questions-

In order to obtain accurate results with the AAS method it was crucial that background corrections were

performed before calculating any concentrations. Background corrections are crucial in order to distinguish

between the signal from the analyte from absorption, emission and scattering of the matrix and the flame.

Absorption due to the absorption matrix can lead to incorrect determinations of the sample absorption as

not all the absorption will be due to the analyte. Light scattering within the instrument will also lead to

negative errors when measuring absorption and concentration. In this experiment background correction was

performed by measuring the absorbance and concentration of blank standards and then subtracting these

values from the values obtained when the analyte is measured. Other techniques that allow background

correction to be performed include the use of a charge injection detector and beam chopping1. Beam

chopping is an effective and common way to differentiate the analyte signal from the signal due to the flame.

The beam chopper works by periodically blocking the light from the lamp before it reaches the sample. The

signal that reaches the detector when the light from the lamp is blocked is the signal due to the flame, as

the chopper rotates the signal is allowed to reach the sample, the signal that reaches the detector whilst

the beam is not blocked is due to analyte and the flame, the difference between the two values allows the

absorption of the analyte alone the be determined.

When preparing unknown and standard solutions it was crucial that all final solutions were made up in

0.1M HNO3 to ensure the matrix was the same for all solutions.

If the matrix in the solutions was different interferences caused by the matrix will cause non-systematic

errors to occur as measurements of different solutions are made, this will lead to poor calibration graphs

and hence poor results.

The Absorption of analyte in the solutions and standards was obtained by a direct read out from the

instrument. Then the concentrations of different solutions were determined by first measuring the

absorbance of the known standards and then plotting a polynomial to the calibration data.

As the unknown samples were ran through the AAS’s computer measured the absorbance and then

determined the concentration of the particular analyte from the calibration curve it generated .

This method is very accurate as it fits a polynomial curve to the data which is crucial as AAS calibration

curves are often not linear over the concentration range used.

The results obtained for the concentrations of the metals in the blank , sediments spike and

blank ,sediment without spike and unknown solutions have shown in the table( 1,2,3&4 ).

The errors reported are more high in case Cd & Zn rather than Pb &Cu. The main reason for the

high errors is due to how the errors were calculated. The sx values from the calibration spreadsheet were

used to calculate the errors using the t statistic. The sx values were obtained by fitting a least squares line

to data obtained from the standards, however as is common in AAS measurements the calibration curve was

not a straight in case Zn & Cd but line instead showed some curvature at higher concentrations (fig. 4a&1a).

The fact that the calibration curve is curved and the sx values are obtained by fitting a straight line

to curved data, results in very high sx values, thus the errors calculated for the unknown & sediment

solutions were most likely much higher than the true uncertainty of the measurement.

A more accurate method to determine the errors would be to carry out several measurements for

each analyte and then use the standard deviation of the calculated concentrations and use the t-test to

determine the error.

http://www.thefreedictionary.com/differentiate


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Another reason for the high errors for some metals, particularly Cd and Zn might due to the

concentration of the analytes being towards the lower end of the working range for the instrument for the

particular analyte.

A more accurate result may be obtained for Pb , Cu & Zn by using some undiluted solution as the

10x dilution was used for the measurement table(6). The undiluted solutions would have 10 times higher

concentration and will thus be closer to the working range of the instrument.

The metal concentrations in both the reference sediment and the Port Kembla 2 sample sediment are

provided in the table 6. Table.2 has shown that the percentage of accuracy of Cu, Pb & Zn was 88.3%, 83.7%

&80%

The concentrations of the analytes in the Port Kembla 2 sediments are provided in the table on the

first page. The concentrations of analyte in the sample sediments was calculated to be slightly higher than

the reference sediments, there are some likely causes for this. Firstly the sample sediments may have been

collected from a different land than the reference sediments. The concentration of analytes in the

sediments is likely to be dependant on location as sediments that are closer to industrial plants are likely to

have a higher concentration of heavy metals. Secondly the process in which the sample sediments were

analyzed and digested, although being identical to that for the reference sediments, may have resulted in

the loss of slightly less components which results in higher concentrations being calculated. However as all

four analytes are found to have a higher concentration in the sample sediment than the reference sediment,

it is unlikely that this is the cause for the different results. Thus the most likely reason for the

concentrations of the analytes being higher in the sample sediment than the reference sediment is due to

the sediments being collected at different places.

The addition of spiking reagents is a very useful way to determine the amount of analyte lost during

an analytical procedure. Spiking also allows the detection of analytes that are below the limit of detection

(LOD) of an instrument by increasing the analytical signal, if a linear response is assumed then concentration

of the analyte can be determined by subtracting the signal for a known amount of additional analyte, this

process is known as standard addition. However during this particular experiment standard additions could

not be used to calculate the concentrations of analyte from the sediment in the solution as a linear response

was not observed. Spiking was instead used in the AAS method to gain an idea of how much analyte was lost

during the sample digestion/preparation steps.

The percentage recovery of spikes in the sample blanks ranged from 15% -120(table.5). Table .5 has

shown that these values indicate that very little analyte was lost during the preparation of the blank

solutions in case Cu,Pb& Zn . The values for Pb , Cu and Zn over 100% can be attributed to either the

experimental uncertainty in the calculated recovery or some contamination of the samples. The source of

contamination is most likely from the glassware , digestion vessels & the air . Table5.has shown the

recovery of sediment(1) and(2) spike was over 100% which can be attributed to some contamination from

the glassware , digestion vessels , chemical & air . it might be caused from the AAs instrument.

The low value for the Zn recovery in the reference + 1ml spiked solution may be caused by one of

two reasons. Firstly a significant amount of Zn may have been lost during the preparation of that particular


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solution, however the cause of this is unknown as no mistakes of spillages occurred during the experiment.

The second reason may be due to small working range for Zn. The working range for Zn for AAS is 0-2mg/L..

The particular digestion procedure used can assist in determining the nature of the heavy metals

present in the sediment. In this investigation a nitric acid/ hydrogen peroxide digestion was used. The

strong acid and oxidizing conditions digests all organic matter and converts them to CO2, H2O and oxides of

nitrogen, sulfur etc. A different digestion procedure that could be used to in this investigation is a

hydroxylamine extraction. Extraction procedures encourage the metals into solution by forming complexes

with them. The use of different extraction reagents will release metals within certain complexes. The

amount of metal forced into solution is very dependant on the form it takes in the sample, thus by using

certain extraction reagents to release metals from particular complexes allows one to determine what form

the metals take in the sample.

The results obtained for ASV are provided in the table .7. The method of standard addition was used

to determine the concentration of the analytes in the solutions. This method was suitable as it meant that

the matrix for the analytes stayed the same as the concentration of analyte was increased by subsequent

spiking. This is of great advantage when the matrix of the solution is either unknown or too complex such

that matrix matching when preparing standards is difficult. The results obtained for the concentration of

analytes in the unknown are significantly lower than those obtained for AAS. This cannot be attributed to

contamination of the unknown during the AAS procedure as the same unknown solution was used to prepare

the unknown solutions for ASV analysis and thus any contamination would carry over. No concentration for

Zn in the unknown & sedment was obtained as the peak areas calculated were incorrect..

The results obtained for lead in both AAS & ASV were closer to each other . however , the result

for Zinc was larger in AAS by about 3 times than ASV. The likely reason for this is that as the solution was

left in the analysis glass for about 1.5 houre, some of the Zinc may have been volatile or might be soled

inside the flask .

Although poor agreement with AAS results was obtained with ASV the relative errors for the

unknown as analyzed in ASV are lower than those obtained in AAS. The reason for this is that ASV produced

linear calibration curves whereas AAS produced curved calibration curves and as a result the linear

regression errors obtained were much higher.

As previously mentioned results for Cu and Zn were hard to obtain with ASV as the baseline was not

calibrated properly for the peaks. It was observed that the peaks for Pb and Cd were quite sharp and

symmetrical whereas the ones for Zn and Cu were smeared out and were not symmetrical. This irregular

shape of the peaks is the most likely cause for the baseline errors obtained. The irregular shape of the

peaks and hence the difficulty in calculating accurate answers from the peak areas is most likely due to the

formation of intermetallic compounds in the mercury film. Cu and Zn are the two most common metals that

are likely to from intermetallic compounds on mercury films in ASV. The formation of intermetallic strips

can lead to negative errors for Zn and positive errors for Cu concentrations. When the Cu-Zn intermetallic

compounds formed it strips at a potential similar to that of copper resulting in an apparent larger peak area

for copper. This results in a smearing of the copper peak and as some Zn is lost to the intermetallic

compound the shape of the Zn peak is also adversely affected. The irregularity of the Zn peak may also in

part be attributed to the handling of the magnetic stirrer with fingers and the consequent contamination

that results.

When performing voltammetry investigations it is crucial that oxygen is removed from the system

prior to analysis. If oxygen present it can be reduced to hydrogen peroxide and even further reduced to

water. If this occurs these reductions will appear as broad peaks which will obscure the peaks due to the

analytes, thus making quantification of the analytes difficult. In this investigation oxygen was removed by

purging nitrogen gas through the system to eliminate and oxygen present.

Upon performing this investigation it became apparent of the relative advantages and disadvantages

of AAS over ASV. The main advantage AAS possesses over ASV is how quick a measurement can be made. In


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this experiment a series of standards were first analyzed by AAS and from the absorbance reading the

program automatically set up a polynomial calibration curve. Once this was done the solution were analyzed at

the appropriate wavelength for the particular analyte and from the absorbance value the program gave a

readout of the concentration of analyte in the solution, thus the calculation time to work out the

concentration of metal in the solution was rather quick. AAS however is rather sensitive to matrix affects

which can have a significant impact on the absorbance and hence concentration. This results in AAS having a

high throughout compared to ASV. A major limitation of AAS over ASV is that AAS can only analyte an

analyte at a time, in order to analyze a new analyte the parameters of the instrument such as wavelength

need to be changed, however in ASV multiple analytes can be measured at once by scanning through a range

of potentials. The analysis of multi component mixtures by ASV also has its disadvantages as if a solution

contains more than one analyte that will strip at similar potentials this will cause significant interference

with the results obtained. The problem with interference caused by other analytes in the solution is not

really a problem in AAS as it uses a very narrow wavelength range produced by a hollow cathode tube that is

different for each analyte, however as mentioned above the matrix itself can interfere with the absorbance.

The detection limits for various analyte using flame atomic absorption are shown below4.

The detection limit of ASV is generally higher than AAS. The higher LOD is due to the process that occurs

during the deposition step. As the potential is applied to reduce the analyte and absorb it onto the electrode

surface the analyte is actually pre-concentrate on the electrode surface as all the analyte is condensed into

a small region, this pre-concentration results in ASV having higher detection limits than AAS5. The LOD of

ASV is proportional to the deposition time, thus the longer the deposition time the higher the sensitivity.

With deposition times as high as 20-30 minutes detection limits of 10-9 are possible6 making ASV are very

important tool for trace analysis however this has the disadvantage of increasing analysis time.

Both AAS and ASV will have similar levels of accuracy and precision. For really low concentrations

ASV will have a better degree of accuracy due to its lower detection limits, however this will be dependant

on the formation of intermetallic compounds. The precision of the result obtained will of course be

dependant on how the uncertainty is calculated. For ASV this was quite simple as the calibration curves were

linear so a linear regression analysis could be performed. For AAS linear regression could not be used to give

an accurate measure of the precision as the calibration curves are not linear. The best way to determine

precision with AAS is to take multiple measurements and use the t-test to gain an estimate of the

uncertainty. The precision of ASV measurements can be further improved using differential pulse

polarograhy. Differential pulse polarography can provide relative precisions of 1-3% for concentrations

grater then 10-7 M are possibele6. It was for this reason that differential pulse methods were used in this

investigation.

AAS offers the highest degree of selectivity of the two methods as each analyte is measured with a

narrow bandwidth of radiation and thus interference due to other analytes are rarely encountered. ASV is

not as selective as AAS as two analytes with similar stripping potentials cannot be analyzed together as they

will interfere and results in inaccurate results for the peak areas.

Metal LOD (ng/ml)

Pb 10

Zn 0.5

Cu 1

Cd 0.4

Metal LOD (mg)

Pb 0.65

Zn 1.9

Cu 0.8

Cd 1.34


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In this investigation both AAS and ASV were used to determine the concentration of four heavy

metals (Pb, Zn, Cu and Cd) in unknown & sediment samples . While the results for each method differ for

reasons explained above a knowledge if the usefulness and limitations of each method was obtained.

AAS has its advantages when multiple analytes with similar stripping potentials in ASV are required

to be analyzed. AAS also offers a quicker analysis time as the instrument can provide a direct readout of the

absorbance and concentration. ASV is most useful with extremely low analyte concentrations (down to 10-9M),

it also offer far greater precision and accuracy for lower concentrations than AAS. ASV is also much more

sensitive to interferences with other analytes with similar stripping potentials meaning it may not be useful

for the analysis of some multi component solutions, in these cases AAS will be the method of choice.

Conclusion- Both AAS and ASV methods were successfully used to determine the trace metal concentrations in sediment

samples and unknown solutions. An understanding of the relative advantages and disadvantage of each

method was obtained along with a working knowledge of how to perform experiments based on the two

methods. Both AAS and ASV are very important techniques for trace metal analysis.

References- 1 Harris, D.C, Quantitative Chemical Analysis (sixth edition), W.H, Freeman and Company,

pg 506-507

2

Chem314 Lab Manual 2007 pg 21-27 3

Copeland, T.R, Osteryoung, R.A Skogerboe, R.K, Elimination of Copper-Zinc Intermetallic

Interferences in Anodic Stripping Voltammetry, Analytical Chemistry, Vol46, No14, pg2093-2097

4 Harris, D.C, Quantitative Chemical Analysis (sixth edition), W.H, Freeman and Company,

pg 509

5

Chem314 Lab Manual 2007 pg 21-27

6

Skoog and Leary, Principles of Instrumental Analysis (fourth edition), Saunders College

Publishing, pg 557-563


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Cd

V0(ml)= Vs

V0(ml)= ML ascorbic I (S+X)= x-axis Function y-axis function

10 acid added signal (uA) Si*Vs/V0 I(S+X) *V/V0

[S]I ppm 0 1.8036 0 1.8036

10 0.04 8.4138 0.04 8.4474552

0.08 18.7381 0.08 18.8880048

[Cd] dul -100 times 0.005480094

[Cd] 0.548009368

y = 213.56x + 1.1708R² = 0.9838

0

2

4

6

8

10

12

14

16

18

20

0 0.02 0.04 0.06 0.08 0.1[Cd] mg/l

Abs

Cd Calibration curve -Unknown


12

V0(ml)= Vs Na+ atomic emission

V0(ml)= ML ascorbic I (S+X)= x-axis Functiony-axis function

50 Volume of standard signal (mV) Si*Vs/V0 I(S+X) *V/V0

[S]I ppm 0 3.13 0 3.13

2640 0.001 5.4 0.0528 5.400108

0.002 7.89 0.1056 7.8903156

0.003 10.3 0.1584 10.300618

0.004 12.48 0.2112 12.4809984

y = 44.702x + 3.1199R² = 0.9995

0

2

4

6

8

10

12

14

0 0.05 0.1 0.15 0.2 0.25


13

pb unknown

V0(ml)= Vs

V0(ml)= ML ascorbic I (S+X)= x-axis Function y-axis function

10 acid added signal (uA) Si*Vs/V0 I(S+X) *V/V0

[S]I ppm 0 2.8595 0 2.8595

10 0.04 7.2999 0.04 7.3290996

0.08 14.1695 0.08 14.282856

0.12 15.2956 0.12 15.4791472

[Pb] dul100 times 0.029151786

[Pb] 2.915178571

y = 112.03x + 3.2657R² = 0.943

0

2

4

6

8

10

12

14

16

18

0 0.02 0.04 0.06 0.08 0.1 0.12 0.14

Asb

Pb Calibration Curve (Un known

[Pb] mg/l


14


15

No. of points x (mg/L) y (Absorbance) xy x^2 d d^2

6 0 0.0008 0 0 -0.07691 0.005916

0.2 0.0769 0.01538 0.04 -0.03507 0.00123

0.5 0.1601 0.08005 0.25 -0.00326 1.06E-05

1 0.3202 0.3202 1 0.071186 0.005067

2 0.5146 1.0292 4 0.094284 0.008889

5 0.884 4.42 25 -0.05022 0.002522

0 0 0 0

0 0 0 0

0 0 0 0

0 0 0 0

0 0 0 0

0 0 0 0

0 0 0 0

0 0 0 0

0 0 0 0

0 0 0 0

0 0 0 0

0 0 0 0

Sums 8.7 1.9566 5.86483 30.29 -2.2E-16 0.023635

+/-

S.d. (y) 0.076869

D= 106.05

m= 0.171302 0.018284

b = 0.077712 0.0410814

Measured y 0.1939 Measured 1 times

Calc. X 0.678263 0.4916377

y = 0.1713x + 0.0777

R² = 0.9564

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0 1 2 3 4 5 6

Ab

so

rbacn

e

[Cd] mg/L

Cd Caibration Curve


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No. of points x (mg/L) y (Absorbacne) xy x^2 d d^2

6 0 -0.0005 0 0 -0.02188 0.000479

0.5 0.0522 0.0261 0.25 -0.01112 0.000124

1 0.113 0.113 1 0.007738 5.99E-05

2 0.2018 0.4036 4 0.012656 0.00016

5 0.4715 2.3575 25 0.030709 0.000943

10 0.8421 8.421 100 -0.0181 0.000328

0 0 0 0

0 0 0 0

0 0 0 0

0 0 0 0

0 0 0 0

0 0 0 0

0 0 0 0

0 0 0 0

0 0 0 0

0 0 0 0

0 0 0 0

0 0 0 0

Sums 18.5 1.6801 11.3212 130.25 4.16E-17 0.002093

+/-

S.d. (y) 0.022876

D= 439.25

m= 0.083882 0.0026736

b = 0.021379 0.0124568


Calc. X 5.549683 0.30487

y = 0.0839x + 0.0214

R² = 0.996

-0.1

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0 2 4 6 8 10 12

Ab

so

rban

ce

[Cu] mg/L

Cu Caibration Curve


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No. of points x (mg/L) y (Absorbacne) xy x^2 d d^2

5 0 0.0003 0 0 -0.00413 1.71E-05

1 0.0234 0.0234 1 0.000239 5.71E-08

2 0.0439 0.0878 4 0.002009 4.03E-06

5 0.1027 0.5135 25 0.004617 2.13E-05

10 0.189 1.89 100 -0.00273 7.48E-06

0 0 0 0

0 0 0 0

0 0 0 0

0 0 0 0

0 0 0 0

0 0 0 0

0 0 0 0

0 0 0 0

0 0 0 0

0 0 0 0

0 0 0 0

0 0 0 0

0 0 0 0

Sums 18 0.3593 2.5147 130 4.34E-17 5E-05

+/-

S.d. (y) 0.004081

D= 326

m= 0.01873 0.0005053

b = 0.004431 0.0025768


Calc. X 0.90064 0.2495144

y = 0.0187x + 0.0044R² = 0.9978

0

0.05

0.1

0.15

0.2

0.25

0 2 4 6 8 10 12

Pb Caibration Curve

ppm

Abs


18

No. of points x (mg/L) y (Absorbance) xy x^2 d d^2

6 0 -0.0004 0 0 -0.07316 0.005352

0.2 0.0665 0.0133 0.04 -0.02618 0.000685

0.5 0.1365 0.06825 0.25 0.013946 0.000195

1 0.2266 0.2266 1 0.05425 0.002943

2 0.3425 0.685 4 0.070557 0.004978

5 0.5313 2.6565 25 -0.03942 0.001554

0 0 0 0

0 0 0 0

0 0 0 0

0 0 0 0

0 0 0 0

0 0 0 0

0 0 0 0

0 0 0 0

0 0 0 0

0 0 0 0

0 0 0 0

0 0 0 0

Sums 8.7 1.303 3.64965 30.29 0 0.015707

+/-

S.d. (y) 0.062664

D= 106.05

m= 0.099593 0.0149052

b = 0.072757 0.0334897


Calc. X -0.19236 0.7226994

y = 0.0996x + 0.0728

R² = 0.9178

-0.1

0

0.1

0.2

0.3

0.4

0.5

0.6

0 1 2 3 4 5 6

Ab

so

rban

ce

[Zn] mg/L

Zn Caibration Curve


19

-3.4694E-18 0.042

sample Abs Zn Conce Sx

Blank (1) 0.004 -0.690385635 0.751327 Recovery%blank(1)117.579 CI= -0.7 2

Blank (2) -0.004 -0.770712852 0.75653 Recovery%blank(2)105.1282 CI= -0.8 2

Blank (1)spike 1.175 11.1 1.59 CI= 11 4.43

Blank (2)spike 2.09 20.3 2.90 spike 1 Recovery% 26.50798 CI= 20 8.05

Sidment(1) 1.279 12.1 1.73 CI= 12.1 4.82

Sidment(2) 1.293 12.3 1.75 spike 2 Recovery% -7.32986 CI= 12 4.88

Sidment(1) spiKe 1.411 13.4 1.92 CI= 13 5.33

Sidment(2)spike 1.22 11.5 1.65 CI= 12 4.60

Unknown (Awad) 0.1387 0.7 0.69 CI= 1 1.92

mg/l mg mg/g mg/kg

Blank (1)spike 11.068 1.107

Blank (2)spike 20.255 2.025

Sidment(1) 12.112 1.211 0.5002 2.421384 2421.38

Sidment(2) 12.252 1.225 0.5003 2.448998 2449.00

Sidment(1) spiKe 13.437 1.344 0.5011 2.681533 2681.53

Sidment(2)spike 11.519 1.152 0.5003 2.302489 2302.49

trace metal analysis in sediments using aas and asv techniques

Science

spike blank

unknown solutions

analysis pb

diluted sediment solutions

samples of blank

final solutions

stock solutions

electrolyte solution