硫代硫酸钠在10-甲基吩噻嗪修饰碳糊电极上的电催化氧化及电分析方法

运用循环伏安法（Cyclic Voltammetry,CV）研究了硫代硫酸钠（Sodium Thiosulfate,ST）在10-甲基吩噻嗪修饰碳糊电极（10-Methylphenothiazine,MPT/CPE）上的电催化氧化行为.结果表明,ST在裸碳糊电极（Carbon Paste Electrode,CPE）上的直接电化学氧化过程十分迟缓,但在MPT/CPE上于0.572 V处出现一不可逆氧化峰,氧化峰电流大幅度增大,表明MPT/CPE对ST电化学氧化有显著的催化作用.同时测定了ST在MPT/CPE上的电极过程动力学参数,即电荷传递系数α=0.62,电催化氧化反应速率常数k=（2.92±0.06）×102（mol/L）-1.s-1.用微分脉冲伏安法（Differtial Pulse Voltam-metry,DPV）测得ST催化氧化反应峰电流与其浓度在2.0×10-4-1.0×10-2mol/L范围内呈良好的线性关系,线性回归方程Ipa（μA）=16.458c（10-3mol/L）＋8.835,R=0.999 4,检测限为6.7×10-5mol/L.对市售ST注射剂含量进行了电化学定量测定,所得结果令人满意。

Electrocatalytic Oxidation of Sodium Thiosulfate at 10-Methylphenothiazine Modified Carbon Paste Electrode and Its Electrochemical Determination

The electrocatalytic oxidation of sodium thiosulfate （ST） at 10-methylphenothiazine （MPT） modified carbon paste electrode （MPT/CPE） was investigated by cyclic voltammetry （CV）. The experiment result showed that the direct electrochemical oxidation of ST itself was very sluggished at carbon paste electrode （CPE）. However, a irreversible oxidation peak appeared at 0. 572 V on the MPT/ CPE, and the peak current was greatly increased, it indicated that an remarkable electrocatalytic effect on ST by MPT/CPE. At the same time kinetics parameters of the electrode reaction were evaluated. The coefficient of electron transfer was 0.62. The reaction rate constant for catalytic oxidation was as （2.92± 0.06） × 10^2 （mol/L）^-1· s ^-1. The catalytic oxidation peak current of ST versus its concentration had a good linear relationship in the concentration range of 2.0 × 10^-4-1.0 × 10 ^-2 mol/L with the correlation coefficient of 0. 999 4, and the detection limit as 6.7× 10^-5 mol/L. The results was quite good and can be applied in the electrochemical determination of the real samples.