Direct voltammetric determination of some heavy metals in uranium

Abstract

The formation of strong complexes between uranium(VI) and various ligands was investigated and a method for the determination of some heavy metals in uranium by differential-pulse stripping voltammetry at a hanging mercury drop electrode was developed. It was found that a carbonate buffer shows the strongest affinity for U^VI and gives the greatest linearity and the best separation between the voltammetric peaks of heavy metal impurities. The concentration of carbonate markedly affects the reduction of the major and the oxidation of the minor constituents of the uranium samples. In 0.1 M carbonate buffer solution (pH 10.0), copper, bismuth, antimony, thallium, lead, cadmium, indium, tin and nickel could be determined at the p.p.b. level without the removal of the uranium matrix. Uranium metal and some uranium(IV) compounds were analysed and good agreement with results obtained by atomic absorption spectrometry was found.