APPLICATION OF CATALYTIC ADSORPTIVE STRIPPING VOLTAMMETRY OF THE COBALT-ALPHA-BENZIL DIOXIME COMPLEX TO ANALYSIS OF COBALT TRACES IN METALLIC ZINC

The catalytic adsorptive stripping voltammetric method with alpha-benz il dioxime and nitrite affords numerous advantages in cobalt determina tion. The detailed conditions of the determination of the cobalt trace s in metallic zinc by catalytic adsorptive stripping voltammetry have been investigated. Both the linear sweep and the differential pulse st ripping modes can be used with similar sensitivity. Possible interfere nces by Mn, Pb, Cu, Ni and Fe are evaluated. In the presence of 5 x 10 (5) fold excess of Zn the linear dependence of the cobalt CASV peak cu rrent on concentration ranged from 0.05 mug/l to 3 mug/l. Optimal cond itions include the accumulation potential of -0.65 V and the accumulat ion time of 10 sec. The results of the determination of 10(-5)% level of Co in the metallic zinc showed good reproducibility (relative stand ard deviation, RSD = 0.07) and reliability.