The electrochemical behaviors and the quantitative analyses of cysteine (RSH) and cystine (RSSR) have been studied with cathodic stripping voltammetry (c.s.v.). The electrode reactions of RSH and RSSR were rather complicated and each voltammogram had two kinds of reduction waves (RSH: first wave; E.=-0.425V, pH 6.0, second wave; Ep=-0.475V, pH 6.0. RSSR: first wage; Ep=-0.455V, pH 6.0, second wave; Ep=-0.97V, pH 6.0). Their electrode reaction schemes were discussed. Concentration effects of c.s.v. were observed with RSH second wave and RSSR first wave. Although these two waves behave adsorptively, RSH second wave didn't have simple saturation characteristic, which indicated the transition of adsorbed species at electrode surface. Furthermore, copper (II) was added to the solutions of RSH and RSSR, respectively, and the electrochemical behaviors of these copper-related waves were also investigated. It is possible to determine RSSR directly with c.s.v. On the other hand, it might be effective to determine RSH indirectly with copper-related wave.
Mendeley出力
