四羧基酞菁钴-半胱胺自组装修饰金电极对烟酰胺腺嘌呤二核苷酸的电催化研究

Study on the Electrochemical Catalysis of NADH by Tetra Carboxyl Cobalt(Ⅱ) phthlocyanine-Cysteamine Self Assembly Au Electrode

本文将（4，4′，4″，4″）四羧基酞菁钴（CoTcPc）共价键合到自组装在Au电极表面的半胱胺单分子层上，获得了自组装单分子膜修饰电极（COTcPc-CysCME），研究了它的电化学性质，并对电极表面进行了表征。电极表面覆盖度为3．7×10^-10mol／cm^2，电子转移速率常数Ks为1．21s^-1。实验表明，在pH7．0的磷酸盐缓冲溶液（PBS）中，CoTcPc／Au对烟酰胺嘌呤二核苷酸（NADH）的氧化具有良好的电催化作用，使NADH在裸金电极上的氧化电位降低了近300mV，催化电流与cNADH在5．0×10^-6～3．2×10^-3mol／L范围有线性关系，检出限为2．8μmol／L。测定了电极催化NADH的米氏催化常数KMapp和催化反应速率常数K。

One monolayer containing thiol-tailed groups was formed through the covalent binding of （4, 4′,4＂, 4″） tetracarboxyl cobalt phthlocyanine（CoTcPc） on a cysteamine-modified gold electrode by using the self-assembly technique. Its electrical properties were studied, and the surface was characterized. The average surface coverage of CoTcPc was 3. 7 × 10^-10 mol/cm^2 , and the electron transfer rate constant （Ks） was 1. 21 s^-1. The modified gold electrode showed an excellent electrocatalytic activity for oxidation of reduced nicotinamide adenine dinueleotide （NADH） in phosphate buffer solution （pH 7.0）, with an overpotential ca. 300 mV which is lower than that at a bare electrode. The steady state current increased linearly with NADH concentration in the range of 5. 0 × 10^-6- 3. 2 × 10^-3 mol/L and the detection limit was 2. 8 μmol/L. The mechanism of the oxidation of NADH catalyzed by CoTcPc modified gold electrode was discussed. The catalytic rate constant K and K^app M of the modified electrode for the oxidation of NADH was determined by rotating disk electrode.