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

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^(-6)mol/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^(-6)mol/L)+5.3(R^2=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%。

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） = 0.6997 c（ 10^-6 mol/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%.