Catalytic Cathodic Stripping Voltammetry of 5-Phenyl-1,3,4-oxadiazole-2-thiol in the Presence of Nickel(II) and Cobalt(II) Ions

5-Phenyl-1,3,4-oxadiazole-2-thiol (POT) and the systems Ni(II)-POT-acetate buffer, Co(II)-POT-acetate buffer were investigated by differential-pulse cathodic stripping voltammetry (DPCSV). The results of the voltammetric measurements show that POT gives a DPCSV signal at about -0.2 V vs Ag|AgCl. The presence of both POT and nickel(II) ions gives rise to a new peak at about -0.6 V; in the presence of cobalt(II) ions a new peak appears at -1.1 V. Based on published results obtained for other sulfur compounds in the presence of Ni(II) or Co(II) ions, the peak at -0.6 V is ascribed to catalytic reduction of Ni(II), and the peak at -1.1 V to hydrogen catalytic discharge. Optimum conditions have been found for the determination of POT by DPCSV. A linear dependence has been found only for the catalytic Ni(II) peak in the region 10-8-10-7 M POT. The calculated limit of detection and limit of quantification are 3.4 × 10-9 and 1.1 × 10-8 mol l-1, respectively.