聚天冬氨酸膜修饰电极测定茶饮料中茶多酚

Determination of Tea Polyphenols in Beverage Using a Glassy Carbon Electrode Modified with Poly-aspartic Acid Film

在0.025 mol/L、pH6.8Na2HPO4-NaH2PO4缓冲溶液中,采用电聚合方法将天冬氨酸修饰到玻碳电极表面,此氨基酸聚合膜修饰电极通过氢键作用有效地提高了茶多酚在电极表面的吸附浓度,显著提高了茶多酚的电化学信号强度。研究了pH、富集时间和扫描速度等因素的影响,建立了水溶液中茶多酚的快速检测方法。在0.9-100.0 mg/L范围内,茶多酚的氧化峰电流与其浓度呈线性关系,由3倍信噪比得出检测限为0.3 mg/L,此方法用于检测茶饮料中的茶多酚,回收率为97.7%-102.4%。

A novel modified electrode was prepared by electro-polymerization of aspartic acid on the surface of a glassy carbon electrode in（0.025） mol/L,pH（6.8） Na2HPO4-NaH2PO4 buffer solution.The film modified electrode enhanced the concentration of tea polyphenols adsorbed on the electrode surface through the formation of hydrogen bond and significantly improved the electrochemical responses of samples.The optimum detection conditions such as pH,accumulation time and scan rate were studied,and a fast analytical method for tea polyphenols was established.In the range of（0.9） to（100.0） mg/L,the oxidation peak current of tea polyphenols display a linear relationship to the concentration,and the detection limit was estimated to be（0.3） mg/L.This method has been adopted to detect the amount of tea polyphenols in beverages,and the recovery is from 97.7% to 102.4%.