甘草苷在玻碳电极上的电化学行为及其测定

Electrochemical Behavior of Liquiritin at Glassy Carbon Electrode and Its Determination

摘要: 在pH 3.00的B-R缓冲溶液中，采用差分脉冲伏安法(DPV)、线性扫描伏安法(LSV)和循环伏安法(CV)研究了甘草苷在玻碳电极上的电化学行为，建立了测定甘草苷的DPV法。实验结果表明，甘草苷于1.16 V (vs.Ag/AgCl)处产生一个氧化峰，峰电流和甘草苷的浓度在2.00×10^-6~3.50×10^-5 mol/L范围内呈良好的线性关系，检出限为8.25×10^-7 mol/L。该法用于实际样品甘草、胃康灵和逍遥丸中黄酮含量的测定(以甘草苷为对照品)，平均回收率分别为97.1%、98.9%和102.0%。此外对电极反应机理作了初步探讨。

Abstract: Electrochemical behavior of liquiritin at glassy carbon electrode (GCE) has been investigated in the Britton-Robinson (B-R) buffer solution (pH=3.00) by differential pulse voltammetry (DPV), cyclic voltammetry (CV) and linear scan voltammetry (LSV). The oxidation peak current at 1.16 V (vs.Ag/AgCl) was proportional to the concentration of liquiritin in the range of 2.00×10^-6 to 3.50×10^-5 mol/L with a detection limit of 8.25×10^-7 mol/L by DPV. The proposed method has been applied to determination of the total flavonoids (liquiritin used as reference substance) in Glycyrrhiza uralensis Fisch., Wei Kang Ling and Xiao Yao Wan, the corresponding average recovery was 96.9%, 99.5% and 102.0%, respectively. The electrochemical reaction mechanism of liquiritin was also studied.