Determination of lead, cadmium, zinc and manganese in copper by anodic stripping voltammetry

Traces of lead, cadmium, zind and manganese in copper and copper compounds are determined, in some cases simultaneously, by anodic stripping voltammetry on a hanging mercury drop electrode. The four metals are separated from the bulk copper(II) by preliminary electrolysis of the copper matrix at a controlled potential on a platinum cathode. The method is applied to commercially available high-purity copper, showing satisfactory sensitivity and accuracy. The determination limits are about 10 -9 M for lead, 5·10 -10 M for cadmium, 10 -9 M for zinc and 10 -8 M for manganese in solution ; this corresponds, respectively, to 0.01, 0.002, 0.003 and 0.03 p.p.m. for a 0.5-g sample in a final volume of 25 ml after separation. However, because of blank values, the final determination limits are about 0.1 p.p.m. for lead and 0.3 p.p.m. for zinc.