Sensitive Determination of (-)-Epigallocatechin Gallate in Tea Infusion Using a Novel Ionic Liquid Carbon Paste Electrode
Sensitive Determination of (-)-Epigallocatechin Gallate in Tea Infusion Using a Novel Ionic Liquid Carbon Paste Electrode
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DOI：
10.1021/jf300498e
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发表时间：
2012-06-27
影响因子：
6.1
通讯作者：
Zhou, Qingli
中科院分区：
文献类型：
--
作者：
Fan, Kai;Luo, Xue;Zhou, Qingli
研究了一种新型离子液体六氟磷酸正辛基吡啶盐（OPFP）碳糊电极（CPE）对绿色茶中黄烷醇主要单体表没食子儿茶素没食子酸酯（EGCG）的电催化氧化。由于OPFP的天然粘度和高电导率，这种新型OPFP-CPE表现出非常有吸引力的特性，如高稳定性和高电化学反应性，低背景电流和宽电化学窗口。因此，该电极是传统化学修饰电极的一个非常好的替代品，因为无需任何进一步的电极修饰即可实现电催化效果。使用CPE和玻碳电极（GCE）进行比较实验。采用OPFP-CPE对EGCG进行了循环伏安分析。在最佳实验条件下，表没食子儿茶素没食子酸酯浓度在5.0 × 10 ~（-7）~ 1.25 × 10 ~（-5）M范围内，峰电流与浓度呈线性关系。检测限（LOD）和定量限（LOQ）分别为1.32 x 10（-7）和4.35 x 10（-7）M。将该方法用于绿色茶汤样品中EGCG的测定，加标回收率为87.62%~ 99.51%。
This paper investigates the electrocatalytic oxidation of (-)-epigallocatechin gallate (EGCG), the main monomer flavanol found in green tea, with a novel ionic liquid, n-octylpyridinium hexafluorophosphate (OPFP) carbon paste electrode (CPE). Due to the natural viscosity and high conductivity of OPFP, this novel OPFP-CPE exhibited very attractive properties, such as high stability and electrochemical reactivity, low background current, and wide electrochemical window. Therefore, this electrode is a very good alternative to traditional chemically modified electrodes because the electrocatalytic effect can achieved without any further electrode modification. Comparative experiments were carried out using CPE and a glassy carbon electrode (GCE). With OPFP-CPE, highly reproducible and well-defined cyclic voltammograms were obtained for EGCG. Under optimal experimental conditions, the peak current of differential pulse voltammetry (DPV) response increased linearly with EGCG concentration over the range of 5.0 x 10(-7)-1.25 x 10(-5) M. The limit of detection (LOD) and the limit of quantification (LOQ) were 1.32 x 10(-7) and 4.35 x 10(-7) M, respectively. The method was applied to the determination of EGCG in green tea infusion samples, and the recovery of the spiked EGCG to the diluted (10-fold) tea extract was from 87.62 to 99.51%.