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

Abstract

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

Surface Characterization of New Azulene-Based CMEs for Sensing

“…The electrochemical experiments were performed using PGSTAT 12 AUTOLAB potentiostat (Utrecht, The Netherlands) connected to a three-electrode cell [19][20][21][22][23]. Bare or modified glassy carbon (GC) disks (3 mm diameter, Metrohm, Herisau, Switzerland) were used as working electrodes.…”

“…CMEs were tested for electrochemical detection of HMs ions in 0.1 M buffer acetate (pH 5.5) solution as supporting electrolyte, following the procedure detailed in [19][20][21][22][23].…”

“…The thiadiazoles are strongly absorbed on mercury, more than cobalt and copper, due to the same complexation effect [19]. The binding of thiadiazole to an azulene residue is an unexploited subject in the literature and creates the premise for recognition of HMs using CMEs based on T. The electropolymerization of similar azulenes [20] can occur by π-steaking [21]. Only few surface studies related to azulene-based CMEs are reported [22,23].…”