Determination of traces of cobalt in zinc matrix by catalytic adsorptive stripping voltammetry at bismuth film electrode

An catalytic adsorptive stripping voltammetric procedure for the determination of cobalt in a zinc matrix at an in situ plated bismuth film electrode was described. The procedure exploits the enhancement effect of a cobalt peak observed in the system Co(II)-dimethylglyoxime-piperazine-1,4-bis(2-ethanesulfonic acid) -cetyltrimethylammonium bromide. Using optimized conditions, in a solution containing 0.01 mol L-1 Zn(II) the calibration plot for Co(II) following accumulation time of 120 s was linear from 2 x 10(-10) to 5 x 10(-8) mol L-1. The detection limit (based on 3 sigma criterion) for Co(II) of 6 x 10(-11) mol L-1 was achieved. The proposed procedure was applied for Co(II) determination in zinc reagent for analysis and in tap water.