Spectroelectrochemical Study Of Copper-Glycine System

Glycine is the simplest amino acid. The study of copper interact with glycine has an important significance for a lot of research like biological process, adsorption configuration on the surface of metal, polishing and electroplating of copper, sensor and so on. In the present work, conventional cyclic voltammetry, in situ thin layer UV-vis spectral analysis and cyclic voltabsorptometry were used to investigate the electrochemical behavior of the copper-glycine system in conventional electrochemical pool and thin-layer electrolytic cell. XRD and XPS analysis represented the features of sCPE surface. In addition, A new CuO modified electrode was prepared and used for the catalytic oxidation of glucose.The results show that the two redox process of copper-glycine system,which took place in the conventional electrochemical pool, were attributed to the redox couples CuClads/Cu and Cu2+/CuClads.Whereas in the thin-layer electrolytic cell, the electro-oxidation of copper in the tested pH range of 4.2-10 leaded to the formation of Cu(I)-glycine complex (CuL2-) through two paths:(a). Successively reacted with chloride ion and glycine to form CuClads and CuL2-; (b). directly converted into soluble CuL2-. Both the paths may exist at a low concentration of glycine in solution. At a high concentration of glycine, all the deposited copper translated by the second way. Before the evolution of chlorine, CuL2-was very stable. The Cu(I)-glycine complex can be destroyed by HClO at relatively positive potentials, then released the Cu+ion, which can be quickly oxidized to produce Cu2+. Then Cu2+reacted with glycine and resulted in to the formation CuL2.Under each peak potential, the material generated on the surface of electrode can be analyzed via XRD and XPS datas. By a viewpoint from the UV-vis spectral analysis and electrochemistry, this work provided the possible reaction mechanisms.In order to get a higher response, the CuO/sCPE was used to catalyzed the oxidation of glucose. The conditions for the preparation of CuO/sCPE were optimized as follows: NaOH concentration,0.1 mol·L-1; CuSO4 concentration,1.0 mmol·L-1 and modified number,50. There came an obvious anodic peak of glucose by CuO modified electrode. It was indicated that the CuO/sCPE have an electrocatalytic effect on the oxidation of glucose.