Determination of Trace of Cobalt in Complex Matrices by Adsorptive Stripping Voltammetry at a Lead Film Electrode

An adsorptive stripping voltammetric procedure for the determination of cobalt in a complex matrices at an in situ plated lead film electrode was described. The procedure exploits the enhancement effect of a cobalt peak observed in the system Co(II)-nioxime-piperazine-1,4-bis(2-ethanesulfonic acid)-cetyltrimethylammonium bromide. The calibration graph was linear from 5 x 10(-10) to 2 x 10(-8) mol L-1 and from 1 x 10(-10) to 1 x 10(-9) mol L-1 for the accumulation times 120 and 600 s, respectively. The detection limit (based on the 3 sigma criterion) for Co(II) following accumulation time of 600 s was 1.1 x 10(-11) mol L-1. The interference of high concentrations of foreign ions and surfactants was studied.