Determination of trace amounts of silver in high purity lead by anodic stripping voltammetry with a glassy carbon electrode

Abstract

A glassy carbon electrode has been applied to the determination of microgram or submicrogram quantities of silver in high purity lead using the general technique of anodic stripping voltammetry. A lead sample (0.11.0 g) is dissolved in nitric acid, the solution evaporated to dryness twice, and the residue dissolved in 20 ml of 0.5 M potassium nitrate. Silver in, the resulting solution is electrodeposited on the polished electrode (surface area: 0.2 cm²) at -0.1 volt vs. S. C. E. for 30 min. with stirring; then the anodic stripping wave in the same solution is recorded by linearly varying the potential over a range of 0.0 to +0.8 volt vs. S. C. E. at a rate of 0.2 volt per min: Two hundredth to 6 ppm of silver in high purity lead can be determined by this method with an accuracy of approximately 10%. The time required for a determination is approximately 90 min.