Trace determination of cadmium by adsorptive cathodic stripping voltammetry

A rapid differential pulse adsorptive cathodic stripping voltammetric method was developed for trace determination of cadmium using 8-hydroxyquinoline as a complexing agent. The base electrolyte used was 0.01M NH4Cl at pH 8.0 at which a well defined peak was observed with Ep at-0.63V. The optimum conditions for the analysis of cadmium include 10.0μM 8-hydroxyquinoline, accumulation potential of -0.4 V (versus Ag/AgCl), accumulation period of 30 s, rest period of 15 s, scan rate of 20 mV/s and pulse amplitude of 30 mV. The peak current was proportional to the concentration of cadmium over the concentration range of 1-25 ppb with a detection limit of 0.2 ppb. The method was applied to the determination of cadmium in water samples. (author)