木犀草素在离子液体修饰电极上的电催化氧化及其测定

用1-丁基-3-甲基咪唑六氟磷酸盐(BMIM]PF₆)疏水性离子液体修饰玻碳电极，在0.2 mol/L磷酸盐缓冲溶液(pH为4.0～8.0)中，运用循环伏安法（CV）和差示脉冲溶出伏安法(DPSV)研究了木犀草素在修饰电极上的电化学行为，建立了测定木犀草素含量的新方法。 实验结果表明，该修饰电极上木犀草素氧化、还原峰电位均负移，峰电流增大。 在-0.2～0.7 V电位区间，pH=7.0的磷酸盐缓冲溶液体系中，木犀草素在修饰电极表面发生的是受吸附控制的准可逆等电子等质子电极反应，电子转移系数α=0.5，吸附量为4.6×10-10 mol/cm²；木犀草素氧化峰电流与其浓度在1.0×10^-10～1.6×10^-8 mol/L范围内呈良好的线性关系，检出限达到3.2×10^-11 mol/L，回收率为98.7%～102.0%；该法操作简单、快速、灵敏、准确；可用于野菊花中类黄酮的测定。

Electrocatalytical Oxidation and Determination of Luteolin at Ionic Liquid Modified Electrode

A glassy carbon electrode modified with hydrophobicity 1-n-butyl-3-methylimidazolium hexafluorophosphate(BMIM]PF₆/GCE) was fabricated. In a 0.2 mol/L phosphate buffer solution(pH 4.0～8.0), cyclic voltammetry and differential pulse stripping voltammetry were used to investigate the electrochemical behavior of luteolin at the modified electrode and a new method for detection of luteolin was established. As a result, an improved response of luteolin at the modified electrode was observed with peak potential shift negatively and increase of peak current. An electrocatalytic quasi-reversible redox process of controlled by absorption was obtained for luteolin on the surface of the modified electrode in a potential range of -0.2～0.7 V at pH=7.0. The charge transfer coefficient(α) and adsorbed amount(Γ) were calculated to be 0.5 and 4.6×10-10 mol/cm², respectively. The anodic current increased linearly with luteolin concentration in a range of 1.0×10^-10～1.6×10^-8 mol/L with a detection limit of 3.2×10^-11 mol/L, and the recovery is between 98.7% and 102.0%. The method is simple, quick, accurate and reliable. It may provide a novel way for flavonoid determination in wild chrysanthemum flower.