Sensitive determination of (-)-epigallocatechin gallate in tea infusion using a novel ionic liquid carbon paste electrode

J Agric Food Chem. 2012 Jun 27;60(25):6333-40. doi: 10.1021/jf300498e. Epub 2012 Jun 15.

Abstract

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 × 10(-7)-1.25 × 10(-5) M. The limit of detection (LOD) and the limit of quantification (LOQ) were 1.32 × 10(-7) and 4.35 × 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%.

Publication types

  • Evaluation Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Carbon / chemistry
  • Catechin / analogs & derivatives*
  • Catechin / chemistry
  • Electrochemistry / instrumentation
  • Electrochemistry / methods*
  • Electrodes
  • Ionic Liquids / chemistry
  • Oxidation-Reduction
  • Sensitivity and Specificity
  • Tea / chemistry*

Substances

  • Ionic Liquids
  • Tea
  • Carbon
  • Catechin
  • epigallocatechin gallate