Determination of Lead, Cadmium, Copper and Zinc in Biological Materials by Anodic Stripping Polarography

Abstract

The high sensitivity of anodic stripping polarography and the simple equipment used make this technique very suitable for determining certain toxic elements, in particular lead and cadmium, as well as essential elements such as zinc or copper. These are found in biological and environmental systems in the concentration range of between nanograms per gram and a few hundred micrograms per gram of sample. The amount of sample required for one analysis is of the order of 100 mg, therefore the blank values introduced by the oxidizing mixture do not represent a serious limitation. After the decomposition of the sample by wet ignition no further separations are required. Copper and lead are determined from a solution made 1.0 M with respect to HC1. For zinc and cadmium the solution is buffered to pH 4.9–5.1. Values are presented for a set of samples among which are standard kale, orchard leaves, and bovine liver. The uptake of lead, zinc, and cadmium has been measured in carrots grown in the environment of a lead-mining area near Meŝica, Slovenia. The results are compared with those from a non-exposed site.