copper ion analysis cory sennett november 15, 2006 ch en 4903
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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
Orion 96-29 IonplusOrion 96-29 Ionplus®® Electrode Electrode
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)
Orion 96-29 IonplusOrion 96-29 Ionplus®® Electrode Electrode
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.
AAnalyst 300AAnalyst 300
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.
AAnalyst 300AAnalyst 300
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