Anodic stripping voltammetry of lead, cadmium and zinc in the presence of copper with an ion-exchange column

Abstract

The determination of lead, cadmium and zinc by anodic stripping voltammetry is made difficult by the presence of large amounts of copper. For lead, ordinarily, 0.10 mg l^–1 of lead is totally suppressed by the presence of 100 mg l^–1 of copper (molar ratio of copper to lead = 3261.5) owing to the very high background currents brought about by undissolved copper atoms. For zinc and cadmium, intermetallic compound formation occurs, which affects the stripping peak currents of both metals. In this work, on-line ion-exchange separation was used prior to differential-pulse anodic stripping voltammetry (DPASV) for the determination of lead, zinc and cadmium in the presence of excess of copper. A commercially available resin, Dowex XFS 43084, allowed suppression of the copper stripping peak. An additional use of the ion-exchange column is to extend the useful range of DPASV for the determination of copper to the millimolar range.