Voltammetric method for direct determination of nickel in natural waters in the presence of surfactants

Voltammetric procedures for direct Ni(II) determination in natural water samples are described. The procedures are based on nickel deposition to the metallic state and then its oxidation in the presence of dimethylglyoxime with the formation of the complex adsorbed on the electrode. Reduction of the complex is exploited in the detection step. Due to the application of a sufficiently negative deposition potential the interference from surfactants is minimized. The detection limits for Ni(II) are 2×10−9 and 2×10−10 mol l−1 for deposition times of 30 and 120 s, respectively. The influence of foreign ions is also presented.