2-Mercapto-5-methyl-1,3,4-thiadiazol (MMTD) and 2,5-dimercapto-1,3,4-thiadiazol (DMTD) were studied by differential pulse cathodic stripping voltammetry (DPCSV). The influence of buffer, pH, accumulation potential ( E acc ), and accumulation time ( t acc ) was investigated. It was stated that the concentration of the buffer affects the height of DPCSV peaks. The best analytical signals were recorded in acetate buffer at pH 4.3 and a buffer concentration of 0.01 mol/L for MMTD and 0.02 mol/L for DMTD, E acc = 0.2 V, and t acc = 120 s for MMTD and 180 s for DMTD. A linear dependence was found from 1 to 8 × 10 -8 mol/L for MMTD and from 1 × 10 -8 to 1 × 10 -7 mol/L for DMTD. The influence of cations [Cu(II), Co(II)] was also considered.L L

Four 6-R-2-thiouracils (R = H, methyl, propyl, benzyl) were examined by differential pulse cathodic stripping voltammetry on mercury electrode. The research led to a very sensitive analytical method that allows their determination on nanomolar level. The detection limit of the 6-propyl derivative is as low as 1.0 × 10-9 mol dm-3. The procedure is very simple and utilizes only most common chemical reagents (such as acetate buffer). The buffer concentration plays an important role in the preconcentration stage, due to the adsorption processes accompanying electrode reactions. The new analytical method was tested with commercial samples of various antithyroid drugs.

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.