L-半胱氨酸自组装膜修饰金电极的电化学特性

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

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0.2mol·L-1的醋酸缓冲溶液中,于-0.2～0.5V(vsSCE)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 quartz crystal mic robalance and cyclic voltammetry we re employed for studying the formation mechanism and electrochemical properties of the self-assemb led membrane formed on the surface of the gold electrode.Experimental resul ts show that specific interaction ex ists between L-cysteine and the gold elec-trode surface,additionally,the L-cysteine molecular pairs were forme d due to the existence of electrostatic at-traction and hydrogen bond between t hemselves in the solution with the pH around isoelectric point.Conse-quently,an L-cysteine self-assemb led bilayer could be formed on the gol d electrode surface.A pair of stable redox peaks were observed with the se lf-assembled bilayer modified gold electrode when potential scanning i n 0.2mol ·L -1 HAc-NaAc buffer solution in the range of -0.2～0.5V(vs SCE).It was also found that the modified electrode has an obvious electrocatalytic effect on the electrooxidation of ascorbic acid.