色氨酸在聚茜素红膜修饰电极上的电化学行为

Electrochemical Behavior of Tryptophan at Poly(Alizarin Red) Film Modified Glassy Carbon Electrode

为建立色氨酸的高灵敏电化学检测方法，研究了聚茜素红（PAR）膜修饰电极的电化学制备，优化了聚合条件．采用循环伏安法和线扫伏安法研究了色氨酸（Try）在该修饰电极上的电化学行为，优化了富集时间、富集电位、测定pH等实验条件．结果表明，该膜修饰电极对色氨酸有良好的富集作用，其氧化峰峰电流明显大于裸玻碳电极．在最佳条件下，氧化峰电流与色氨酸浓度在9．0×10^-8～9．0×10^-7mol/L、1．0×10^-6～1．0×10^-5mol/L之间呈线性关系，相关系数为0．9987、0．9976，检出限为8．0×10^-8mol/L．将此法用于口服液中色氨酸的测定，结果令人满意．

For the sensitive determination of tryptophan （Try） with electrochemical technique, a poly （alizarin red） （PAR） film electrode was fabricated by electropolymerization of alizarin red on a glassy carbon electrode with optimized experimental parameters for the electropolymerization. Cyclic voltammetry （CV） and linear sweep voltammetry （LSV） were used to study the electrochemical behavior of tryptophan （Try） on this modified glassy carbon electrode. Parameters such as voltammetric sweeping segments for the electrochemical polymerization, pH, accumulation potential and accumulation time on the electrochemical behaviors of tryptophan were optimized. Compared with the bare glassy carbon electrode, Try can be adsorbed on the PAR film electrode effectively, the oxidation peak current of tryptophan was increased remarkably. Under the optimal conditions, the oxidation peak current is proportional to tryptophan concentration in the range of 9.0×10^-8 to 9. 0×10^-7 mol/L and 1.0×10^-6 to 1.0×10^5mol/L with a detection limit of 8.0 × 10^-5mol/L. The results showed that none of 18 amino acids interfered with the determination of Try. The proposed procedure is successfully applied to the determination of tryptophan in a commercial amino acid oral solution.