Comparative Study to Evaluate the Feasibility of Sono-Anodic and Sono-Cathodic Stripping Voltammetry for the Determination of Pb in a Cu-Pb Alloy

Abstract

The complicated analytical challenge of lead determination in the presence of high levels of copper, has been investigated using anodic and cathodic stripping voltammetry, on a variety of mercury free electrode substrates. CSV was found to be ideally suited towards lead determination in a predominantly copper matrix, due to the lack of interference from copper ions on the anodic electrochemistry of lead. A CSV technique, incorporating the use of power-ultrasound and a borondoped diamond electrode is presented. The sono-CSV technique has been optimised to give a lower limit of detection of aqueous Pb²⁺ ions of 1.6×10^-9 M for a 300 s PbO₂ deposition, requires no solution degassing, is mercury-free and totally free from copper-intermetallic interference. As an extreme example, the technique was applied successfully to the determination of lead content of a copper-lead alloy, after a simple acid digestion protocol. Excellent correlation was observed between the known lead level and experimental results, with the technique being sensitive towards the detection of 3.3×10^-4% (w/w) lead in copper, for the analysis of a 10 mg sample.