Adsorptive stripping voltammetry of nickel and cobalt at in situ plated lead film electrode

In situ plated lead film electrode was proposed for adsorptive stripping voltammetric determination of nickel and cobalt in the presence of dimethylglyoxime. The stabilisation of lead at mild alkaline pH used for determination of these elements was achieved by increasing the concentration of dimethylglyoxime in the supporting electrolyte and so ensuring complexation of Pb(II) by dimethylglyoxime. At such conditions, Bi(III) ions undergo hydrolysis and so bismuth film cannot be plated in situ. The application of an in situ plated lead electrode leads to a shortening of the time of the measurements and requiring no pre-plating with medium exchange. The Ni(II) and Co(II) signals at lead film electrode are better resolved than at bismuth film electrode. The linear calibration graphs for Ni(II) and Co(II) in the range from 5 × 10−9 to 1 × 10−7 mol L−1 and from 1 × 10−9 to 1 × 10−7 mol L−1 were obtained, respectively. The method was applied to Ni(II) and Co(II) determination in certified reference materials.