Cathodic Stripping Voltammetry of 2-Mercapto-5-Methyl-1,3,4-Thiadiazol and 2,5-Dimercapto-1,3,4-Thiadiazol at a Controlled-Growth Mercury Drop Electrode

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.