聚苯胺薄膜修饰电极对抗坏血酸的电催化氧化

ELECTROCATALYTIC OXIDATION OF ASCORBIC ACID AT POLYANILINE FILM MODIFIED GLASSY CARBON ELECTRODES

本文表明聚苯胺(PAn)薄膜修饰电极对水溶液中的抗坏血酸(AH_2)在较宽的pH范围和较宽的浓度范围内均有良好的电催化氧化作用,为EC平行催化过程。利用旋转圆盘电极(RDE)进行了催化过程动力学分析,求出了催化反应动力学参数。在抗坏血酸浓度10^(-2)～10^(-6)mol·L^(-1)范围内,催化峰电流与AH_2浓度均成良好的线性关系,且PAn薄膜修饰电极具有很好的稳定性,有应用分析抗坏血酸的意义。

A conducting polyaniline (PAn) film modified glassy carbon (GC) electrodewas prepared by electrochemical polymerization. The electrochemical behavior ofascorbic acid (AH_2) in aqueous solution at this PAn modified electrode was studiedin detail. The experimental results show that PAn film modified electrode has goodelectrocatalytic activity on the oxidation of ascorbic acid in aqueous solution over awide range of pH value, among which pH 4 is the optimum condition.The oxidationprocess of ascorbic acid at PAn film electrode can be regarded as an EC catalyticmechanism. The kinetic process of the catalytic reaction was investigated by rotatingdisk electrode (RDE) coated with PAn films. The rate constant of the catalyticreaction was evaluated. The catalytic peak currents are proportional to the concentra-tions of ascorbic acid in the range of 5×10^(-2)-1×10^(-6)mol2·L^(-1).The PAn film elec-trodes give very stable responce for the oxidation of ascorbic acid. The presentinvestigation shows the posibility of using PAn film modified electrode for the deter-mination of ascorbic acid.