色氨酸在Nafion-聚半胱氨酸修饰电极上的电化学行为及分析测定

Electrochemical behavior and determination of tryptophan at the nafion and L-cysteine modified electrode

摘要: 采用滴涂和电聚合的方法构筑Nafion-聚半胱氨酸修饰的玻碳电极(Nafion/L-cys/GCE),采用循环伏安法(CV)研究色氨酸在此修饰电极上的电化学行为,利用线性扫描伏安法(LSV)对色氨酸进行定量分析。结果表明,该修饰电极对色氨酸电化学氧化具有明显催化作用。色氨酸浓度在0.4×10^-6~40.0×10^-6mol/L范围内与氧化峰电流有良好线性关系,回归方程为I_pa(μA)=0.6997c(10^-6mol/L)+5.3(R²=0.9844),检测限为1.0×10^-7 mol/L。该方法用于香蕉中色氨酸的检测,回收率为95%~98%。

Abstract: Nafion and Poly-cysteine modified glass carbon electrode(Nafion/L-cys/GCE)was constructed by electro-polymerization and dropping. The electrochemical behavior of tryptophan was investigated and the quantitative determination of tryptophan was performed by cyclic voltammetry(CV)and linear scanning voltammetry(LSV),respectively. The Nafion/L-cys/GCE displayed superior electrocatalytic activity towards the oxidation of Trp. Under the optimum experimental condition,the peak current of tryptophan was proportioned to its concentration in the range from 0.4×10^-6 to 40.0×10^-6 mol/L. The linear regression equation was I_pa(μA)=0.6997c(10^-6mol/L)+5.3(R²=0.9844)with detection limit of 1.0×10^-7 mol/L. The proposed method was successfully applied for the determination of Trp in fresh banana samples. The recovery was 95%~98%.