Copper Ion Analysis Cory Sennett November 15, 2006 CH EN 4903

Overview Devices used to detect copper ion concentration in solution Devices used to detect copper ion concentration in solution Analysis of copper ion concentration in an unknown sample Analysis of copper ion concentration in an unknown sample Conclusions Conclusions

Devices Copper specific electrode Copper specific electrode Orion Ionplus ® cupric electrode Orion Ionplus ® cupric electrode Atomic absorption spectroscopy (AA) Atomic absorption spectroscopy (AA) Perkin-Elmer AAnalyst 300 Perkin-Elmer AAnalyst 300

Orion Ionplus ® Electrode Ion Selective Electrode (ISE) Ion Selective Electrode (ISE) Measures electric potential across a membrane Measures electric potential across a membrane Compares the potential to a reference, which gives a net charge Compares the potential to a reference, which gives a net charge The net charge is directly proportional to the concentration The net charge is directly proportional to the concentration

Orion Ionplus ® Electrode Analysis of unknown sample Analysis of unknown sample Standards Standards 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. 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. 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 Ionplus ® Electrode Procedure Procedure Calibration curve created using standards (Figure 1) Calibration curve created using standards (Figure 1) Use of linear least squares to fit data Use of linear least squares to fit data Table 1 Calibration data for Orion Electrode Table 1 Calibration data for Orion Electrode Concentration (gm/L) Ion Ion Ion Average Stdev Slope: 0.001Intercept: R 2 : Determine unknown concentration Determine unknown concentration

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

Orion Ionplus ® Electrode Results Results 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 300 Uses absorption of light to measure concentration of gas- phase atoms Uses absorption of light to measure concentration of gas- phase atoms Atomizes liquid sample Atomizes liquid sample Vaporizes liquid sample across slot burner Vaporizes liquid sample across slot burner Concentration can be approximated using Beer-Lambert Law Concentration can be approximated using Beer-Lambert Law A=  lc A=  lc Where A is the absorbance,  is the absorption coefficient, l is the distance the light travels through the sample and c is the concentration of absorbing species.

AAnalyst 300 Analysis of unknown sample Analysis of unknown sample Standards Standards 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. 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.

AAnalyst 300 Procedure Procedure Calibration curve created using standards (Figure 2) Calibration curve created using standards (Figure 2) Use of linear least squares to fit data Use of linear least squares to fit data Table 2 Calibration data for AA Table 2 Calibration data for AA Concentration (gm/L)Absorb. Absorb. Absorb. Average Stdev Slope: Intercept: 0.101R 2 : Determine unknown concentration Determine unknown concentration

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

AAnalyst 300 Results Results 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 Results Orion Electrode Orion Electrode 0.625±0.014 gm/L (confidence level 95%) 0.625±0.014 gm/L (confidence level 95%) AAnalyst ±0.016 gm/L (confidence level 95%) Actual concentration of unknown sample Actual concentration of unknown sample gm/L gm/L

Conclusions The Orion Electrode gave a more accurate result for the unknown sample. The Orion Electrode gave a more accurate result for the unknown sample. More experimentation required to determine precision and accuracy over a broad range. More experimentation required to determine precision and accuracy over a broad range.

Questions?

References Schwedt, Georg The Essential Guide to Analytical Chemistry, John Wiley & Sons, Inc., New York (1997). Schwedt, Georg The Essential Guide to Analytical Chemistry, John Wiley & Sons, Inc., New York (1997). Omega Engineering Inc. Ion Selective Electrodes: Measurement Considerations, (2006) Omega Engineering Inc. Ion Selective Electrodes: Measurement Considerations, (2006) Wikimedia Foundation, Inc. Wikimedia Foundation, Inc.