离子液体BMIMPF6修饰碳糊电极电化学测定维生素E

用疏水性离子液体1-丁基-3-甲基咪唑六氟磷酸(BMIM]PF6)作粘合剂制备了离子液体修饰碳糊电极(IL/CPE)。采用循环伏安法(CV)研究了维生素E(vitamin E,VE)的氧化产物生育酚红在IL/CPE和未修饰碳糊电极(CPE)上的电化学行为,结果表明生育酚红在IL/CPE上氧化过程更易于进行,峰电流响应ip也明显增加,表明IL/CPE对生育酚红的氧化还原反应具有良好的电催化作用。同时测定了电极过程的动力学参数:电荷转移系数α=0.8746,扩散系数D=1.65×10-3cm2/s,电极反应速率常数kf=6.64×10-2cm/s。采用方波伏安法(SWV)发现生育酚红氧化峰电流与其浓度在1.53×10-4mol/L～8.39×10-7mol/L范围内呈线性关系,检出限为1.58×10-8mol/L。该法可用于VE实际样品的分析测定。

Electrochemical determination of vitamin E at ionic liquid BMIMPF6 modified carbon paste electrode

An ionic liquid modified carbon paste electrode(IL/CPE)was fabricated by employing hydrophobic ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate(PF6)as a binder.The electrochemical behavior of tecored(the oxidation product of vitamin E)at the IL/CPE and non-modified CPE was investigated by cyclic voltammetry(CV).The experimental results show that the oxidation process of tecored at the IL/CPE was much more easier,while peak current ip was significantly increased,which indicated that IL/CPE had electrocatalytic activity toward the redox of vitamin E.At the same time some kinetics parameters of the vitamin E were determined at IL/CPE:electron transfer coefficient α is 0.8746,the Diffusion coefficient D is 1.65×10-3cm2/s and the electrode reaction rate constant kf is 6.64×10-2cm/s.The linear relationship between values of oxidation peak current and concentration of vitamin E was found in the range from 1.53×10-4 mol/L to 8.39×10-7mol/L with a detection limit of 1.58×10-8mol/L(S/N=3)by Square Wave Voltametry(SWV)method.The proposed method was applied to directly analysis and determines vitamin E samples.