谷胱甘肽在咖啡酸修饰碳糊电极上的电催化氧化及电分析方法

目的: 研究了谷胱甘肽(还原型,glutathione,GSH)在咖啡酸(Caffeic acid,CFA)修饰碳糊电极(CFA/CPE)上的电催化氧化行为和电化学分析方法。 方法: 循环伏安法(CV),计时电流法(CA)和线性扫描伏安法(LSV)。 结果: GSH在碳糊电极(CPE)上的直接电化学氧化过程十分迟缓,CFA/CPE对GSH电化学氧化具有良好的催化作用。同时测定了GSH在CFA/CPE上的电极过程动力学参数,用LSV法测得催化氧化峰电流与GSH在5.0×10^-5～1.0×10^-3 mol·L^-1浓度范围内呈良好线性关系,线性回归方程为I_pa(μA)=2.003c (10^-3 mol·L^-1) + 3.448,r=0.9989,检出限为4.0×10^-5 mol·L^-1。 结论: CFA/CPE对GSH电化学氧化具有良好的催化作用,该方法可用于市售还原型谷胱甘肽药物含量的电化学定量测定。

Objective: Electrocatalytic oxidation behaviors and electrochemical determination of glutathione(GSH) at carbon paste electrode(CPE) and caffeic acid modified carbon paste electrode(CFA/CPE) were investigated. Methods: Cyclic voltammetry(CV),chronoamperometry(CA) and linear sweep voltammetry(LSV). Results: It was found that glutathione itself showed a poor electrochemical response at carbon paste electrode(CPE),the electrochemical behaviors could be greatly enhanced by using CFA/CPE,which enables a sensitive electrochemical determination of the substrate glutathione.The kinetic parameters of the reaction were evaluated.The catalytic oxidation peak currents of glutathione versus its concentration had a good linear relationship in the concentration range of 5.0×10^-5～1.0×10^-3 mol·L^-1 with the correlation coefficient of 0.9989,and the detection limit of 4.0×10^-5 mol·L^-1by LSV. Conclusion: CFA/CPE can catalyze the oxidation of GSH well.Furthermore,the proposed method can be applied in the electrochemical determination of glutathione content with real samples with the simple manipulation.