Simple, insensitive to environmental matrix interferences method of trace cadmium determination in natural water samples

Abstract

A simple, fast, and inexpensive anodic stripping voltammetric procedure for trace determination of cadmium in natural water samples containing high concentrations of surface-active substances was described. It was proved that interferences from the organic matrix such as surface-active substances could be removed by the addition of Amberlite XAD-7 resin to the analyzed sample prior to the voltammetric measurement. A renewable mercury film silver-based electrode (Hg(Ag)FE) was used as the working electrode. The following optimum conditions were found: 0.1 mol L −1 acetic acid, accumulation potential of − 0.8 V, and accumulation time of 30 s. The linear range of Cd(II) was observed over the concentration range from 5 × 10 −8  mol L −1 to 6 × 10 −5  mol L −1 , with a correlation coefficient equal to 0.997. The detection limit of Cd(II) for preconcentration time of 30 s was 1.3 × 10 −8  mol L −1 . The proposed procedure was successfully tested for the detection of cadmium in different non-pretreated and non-deaerated real water samples.