copper ion analysis cory sennett november 15, 2006 ch en 4903

Copper Ion AnalysisCopper Ion Analysis

Cory SennettCory SennettNovember 15, 2006November 15, 2006

CH EN 4903CH EN 4903

OverviewOverview

Devices used to detect copper ion concentration in Devices used to detect copper ion concentration in solutionsolution

Analysis of copper ion concentration in an unknown Analysis of copper ion concentration in an unknown samplesample

ConclusionsConclusions

DevicesDevices

Copper specific electrodeCopper specific electrode Orion 96-29 IonplusOrion 96-29 Ionplus®® cupric electrode cupric electrode

Atomic absorption spectroscopy (AA)Atomic absorption spectroscopy (AA) Perkin-Elmer AAnalyst 300Perkin-Elmer AAnalyst 300

Orion 96-29 IonplusOrion 96-29 Ionplus®® Electrode Electrode

Ion Selective Electrode (ISE)Ion Selective Electrode (ISE) Measures electric potential across a membraneMeasures electric potential across a membrane Compares the potential to a reference, which gives Compares the potential to a reference, which gives

a net chargea net charge The net charge is directly proportional to the The net charge is directly proportional to the

concentrationconcentration


Analysis of unknown sampleAnalysis of unknown sample StandardsStandards

Solutions created using approximately 0.50 gm/L, 0.75 gm/L Solutions created using approximately 0.50 gm/L, 0.75 gm/L and 1.00 gm/L cupric standard mixed with 15 ml of water.and 1.00 gm/L cupric standard mixed with 15 ml of water.

0.1 ml of Ionic Strength Adjuster added to each standard.0.1 ml of Ionic Strength Adjuster added to each standard. Allows for consistent pH level and more accurate readings Allows for consistent pH level and more accurate readings

Orion 96-29 IonplusOrion 96-29 Ionplus®® Electrode Electrode ProcedureProcedure

Calibration curve created using standards (Figure 1)Calibration curve created using standards (Figure 1) Use of linear least squares to fit dataUse of linear least squares to fit data

Table 1 Calibration data for Orion ElectrodeTable 1 Calibration data for Orion Electrode

Concentration (gm/L)Concentration (gm/L) Ion Ion Ion Ion Ion Ion Average Average Stdev Stdev0.400.40 625.3 625.3 625.2 625.2 600.2 600.2 616.9 616.9 14.5 14.50.750.75 1184.01184.0 1201.0 1201.0 1179.0 1179.0 1188.0 1188.0 11.5 11.51.061.06 1630.01630.0 1588.0 1588.0 1615.0 1615.0 1611.0 1611.0 21.3 21.3

Slope: 0.001Slope: 0.001 Intercept: -0.020Intercept: -0.020 RR22: 0.997: 0.997

Determine unknown concentrationDetermine unknown concentration

Figure 1 Orion electrode calibration curve showing standard solution concentration versus ion concentrations.

500

700

900

1100

1300

1500

1700

0.35 0.45 0.55 0.65 0.75 0.85 0.95 1.05

Concentration (g/L)

Ion

Co

nc

en

tra

tio

n (

x1

0-5

M)

Standard 1

Standard 2

Standard 3

Average

Linear (Average)


ResultsResults 0.625±0.014 gm/L (confidence level 95%)0.625±0.014 gm/L (confidence level 95%) Reproducibility: ±2.2%Reproducibility: ±2.2%

AAnalyst 300AAnalyst 300

Uses absorption of light to measure concentration of gas-Uses absorption of light to measure concentration of gas-phase atomsphase atoms

Atomizes liquid sampleAtomizes liquid sample Vaporizes liquid sample across slot burnerVaporizes liquid sample across slot burner Concentration can be approximated using Beer-Lambert Concentration can be approximated using Beer-Lambert

LawLaw

A=A=lclc

WhereWhere A A is the absorbance,is the absorbance, is the absorption coefficient,is the absorption coefficient, l l is the distance the light is the distance the light travels through the sample andtravels through the sample and c c is the concentration of absorbing species.is the concentration of absorbing species.


Analysis of unknown sampleAnalysis of unknown sample StandardsStandards

Solutions created using approximately 0.50 gm/L, 0.75 gm/L Solutions created using approximately 0.50 gm/L, 0.75 gm/L and 1.00 gm/L cupric standard mixed with 15 ml of water.and 1.00 gm/L cupric standard mixed with 15 ml of water.

AAnalyst 300AAnalyst 300 ProcedureProcedure

Calibration curve created using standards (Figure 2)Calibration curve created using standards (Figure 2) Use of linear least squares to fit dataUse of linear least squares to fit data

Table 2 Calibration data for AATable 2 Calibration data for AAConcentration (gm/L)Concentration (gm/L) Absorb.Absorb. Absorb. Absorb. Absorb. Absorb. Average Average Stdev Stdev

0.400.40 0.0050.005 0.005 0.005 0.005 0.005 0.005 0.005 0.000 0.0000.750.75 0.0100.010 0.010 0.010 0.010 0.010 0.010 0.010 0.000 0.0001.061.06 0.0150.015 0.016 0.016 0.016 0.016 0.016 0.016 0.001 0.001

Slope: 61.899Slope: 61.899 Intercept: 0.101Intercept: 0.101 RR22: 0.995: 0.995

Determine unknown concentrationDetermine unknown concentration

0.004

0.006

0.008

0.010

0.012

0.014

0.016

0.30 0.40 0.50 0.60 0.70 0.80 0.90 1.00 1.10

Concentration (g/L)

Ab

so

rba

nc

e

Standard 1

Standard 2

Standard 3

Average

Linear (Average)

Figure 2 AA calibration curve showing standard solution concentrations versus absorbance.


ResultsResults 0.788±0.016 gm/L (confidence level 95%)0.788±0.016 gm/L (confidence level 95%) Reproducibility: ±2.0%Reproducibility: ±2.0%

Comparison of ResultsComparison of Results

OrionOrion Electrode Electrode 0.625±0.014 gm/L 0.625±0.014 gm/L

(confidence level 95%)(confidence level 95%)

AAnalyst 300AAnalyst 300 0.788±0.016 gm/L 0.788±0.016 gm/L

(confidence level 95%)(confidence level 95%)

Actual concentration of unknown sampleActual concentration of unknown sample 0.635 gm/L0.635 gm/L

ConclusionsConclusions

The Orion Electrode gave a more accurate result The Orion Electrode gave a more accurate result for the unknown sample.for the unknown sample.

More experimentation required to determine More experimentation required to determine precision and accuracy over a broad range.precision and accuracy over a broad range.

Questions?Questions?

ReferencesReferences Schwedt, Georg Schwedt, Georg The Essential Guide to Analytical Chemistry,The Essential Guide to Analytical Chemistry, John Wiley & Sons, Inc., New John Wiley & Sons, Inc., New

York (1997).York (1997). Omega Engineering Inc. Omega Engineering Inc. Ion Selective Electrodes: Measurement Considerations, Ion Selective Electrodes: Measurement Considerations,

http://www.omega.com/techref/ph-5.htmlhttp://www.omega.com/techref/ph-5.html (2006)(2006) Wikimedia Foundation, Inc. http://www.wikipedia.comWikimedia Foundation, Inc. http://www.wikipedia.com

copper ion analysis cory sennett november 15, 2006 ch en 4903

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