利用循环伏安法制备了聚缬氨酸修饰电极。聚缬氨酸修饰电极对曲酸的电化学氧化具有明显的催化作用。研究了曲酸在聚缬氨酸修饰电极上的电化学行为,建立了测定曲酸的电化学分析新方法。研究了醋酸盐缓冲溶液pH值对曲酸电化学行为的影响。结果表明,曲酸氧化峰电位随pH值升高发生负移,在pH=5.4时,曲酸在修饰电极上呈现灵敏的氧化峰。曲酸在聚缬氨酸修饰电极上的氧化峰峰电流与其浓度在7.00×10-6~6.50×10-4mol/L范围内呈良好线性关系;相关系数为0.998 3;检出限为8.50×10-7mol/L。其回归方程为:i pa(A)=0.048c+3.89×10-6。该修饰电极具有良好的灵敏度、选择性和稳定性,可用于食品中曲酸分析。

A poly( valine) modified electrode was prepared by cyclic voltammetry.The modified electrode showed an excellent electrocatalytical effect on the oxidation of kojic acid.The voltammetric behavior and electrochemical analysis method of kojic acid were studied on the modified electrode.The effect of pH value on the response of kojic acid was studied in acetate buffer solutions( ABS).The results show that the oxidation peak potential of kojic acid shift negatively with increasing of pH value and a well-defined oxidation wave was obtained in ABS of pH = 5.4.The oxidation peak currents of kojic acid increased linearly with its concentration in the range of 7.00 × 10- 6~ 6.50 × 10- 4mol/L.The linear regression equation is i pa( A) = 0.048c + 3.89 × 10- 6,correlation coefficient is 0.998 3,the detection limit( S/N = 3) is 8.50 × 10- 7mol/L.The poly( valine) modified electrode showed good sensitivity,selectivity,and stability.It can be applied to the analysis of kojic acid in food.