L-半胱氨酸自组装膜修饰金电极的电化学特性

采用电化学石英晶体微天平（EQCM）和循环伏安法（CV）研究了L-半胱氨酸在金电极表面形成自组装膜的机理及其电化学性质.结果表明, L-半胱氨酸分子在金电极表面有特性吸附，而且在等电点pH附近因静电引力和氢键作用形成分子对，从而自组装形成双层膜.该膜电极在0.2 mol•L－1的醋酸缓冲溶液中，于－0.2～0.5 V(vs SCE)间CV扫描出现了一对稳定的氧化还原峰，并对抗坏血酸的氧化有良好的催化作用.

Electrochemical Properties of L- cysteine Self- assembled Membrane Modified Gold Electrode

Electrochemical quartz crystal microbalance and cyclic voltammetry were employed for studying the formation mechanism and electrochemical properties of the self-assembled membrane formed on the surface of the gold electrode. Experimental results show that specific interaction exists between L-cysteine and the gold electrode surface, additionally, the L-cysteine molecular pairs were formed due to the existence of electrostatic attraction and hydrogen bond between themselves in the solution with the pH around isoelectric point. Consequently, an L-cysteine self-assembled bilayer could be formed on the gold electrode surface. A pair of stable redox peaks were observed with the self-assembled bilayer modified gold electrode when potential scanning in 0.2 mol•L－1 Hac-NaAc buffer solution in the range of －0.2～0.5 V (vs SCE). It was also found that the modified electrode has an obvious electrocatalytic effect on the electrooxidation of ascorbic acid.