The Direct Determination, by Differential Pulse Anodic-Stripping Voltammetry at the Thin Mercury-Film Electrode, of Cadmium, Lead, and Copper

摘要

This report describes the development and application of a voltammetric procedure for the direct, simultaneous determination of cadmium, lead, and copper in three SAROC reference materials (carbonatite, magnesite, and quartz). The electrolyte was a mixture of 1 M ammonium chloride, 0,1 M citric acid, and 0,025 M ascorbic acid. No interferences were encountered from Fe(III), As(III), Sb(V), Tl(I), or In(III) at the concentrations present in the samples. Intermetallic interferences were eliminated by the use of thin mercury-film electrodes not less than 80 nm thick. Limits of detection were determined by the degree to which the supporting electrolyte could be purified, and were estimated to be 10 ng/g, 250 ng/g, and 150 ng/g for cadmium, lead, and copper respectively.