Determination of copper in whole blood by differential pulse adsorptive stripping voltammetry

A selective and sensitive method for determination of copper in blood by adsorptive differential pulse cathodic stripping voltammetry is presented. The method is based on adsorptive accumulation of the complexes of Cu (II) ions with benzenesulfonyl hydrazide onto hanging mercury drop electrode (HMDE), followed by the reduction of the adsorbed species by differential pulse cathodic stripping voltammetry. The effect of various parameters such as supporting electrolyte, concentration of benzenesulfonyl hydrazide, accumulation potential, accumulation time and stirring rate on the selectivity and sensitivity were studied. The optimum conditions for determination of copper include perchloric acid 0.03 M, concentration of benzenesulfonyl hydrazide 7.5×10 -5 M, the accumulation potential of -350 mV (vs. Ag/AgCl), the accumulation time of 50 s, and the scan rate of 50 mV s -1 . Under optimized conditions, linear calibration curves were established for the concentration of Cu (II) in the range of 0.62-275 ng mL -1 , with detection limit of 0.186 ng mL -1 for Cu (II). The procedure was successfully applied to the determination of copper ion in whole blood samples.