Direct Determination of Cadmium Traces in Natural Water by Adsorptive Stripping Voltammetry in the Presence of Cupferron as a Chelating Agent

摘要

A sensitive, simple and fast adsorptive stripping voltammetric procedure for trace determination of cadmium in natural samples containing high concentrations of surface active substances and humic substances has been developed. The method is based on adsorptive accumulation of the Cd(II)-cupferron complex onto a hanging mercury drop electrode, followed by the reduction of the adsorbed species by a voltammetric scan using differential pulse modulation. The detection limit was 3×10 ~(-10)mol L ~(-1) (33.6ng L ~(-1)) with an accumulation time 30s. The procedure was applied to the determination of Cd(II) in natural water samples without any pre-treatment with satisfactory results.