Differential pulse adsorption stripping voltammetric determination of copper(II) with 2-mercaptobenzimidazol at a hanging mercury-drop electrode

Copper(II) was selectively accumulated on a hanging mercury-drop electrode by using 2-mercaptobenzimidazole. Ensuing measurements were carried out by differential pulse adsorption stripping voltammetry. Factors affecting the accumulation, reduction, and stripping steps were investigated and a proced ure was developed. The optimum conditions for the analysis of copper were p H 5.0, 5.33 x 10(-5) M 2-mercaptobenzimidazole and an accumulation potentia l of -0.10 V (VS. Ag/AgCl). A linear range was obtained in the concentratio n range 0.2 - 100 ng/ml with a 90 s accumulation Lime and a scan rate of 16 mV/s. For ten successive determinations of 1.0, 20.0 and 70.0 ng/ml copper (II), relative standard deviations of 4.2, 3.5 and 2.8%, respectively, were obtained. The developed method was applied to the determination of copper in commercial salts and aluminium alloys.