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

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%.

[1]  H. Ikigai,et al.  Inhibitory effects of (-)-epigallocatechin gallate on the life cycle of human immunodeficiency virus type 1 (HIV-1). , 2002, Antiviral research.

[2]  Huafu Wang,et al.  Isocratic elution system for the determination of catechins, caffeine and gallic acid in green tea using HPLC , 2000 .

[3]  N. Yang,et al.  Flow injection chemiluminescent detection of gallic acid in olive fruits , 2007 .

[4]  T. Shimamura,et al.  Epigallocatechin Gallate Synergistically Enhances the Activity of Carbapenems against Methicillin-Resistant Staphylococcus aureus , 2002, Antimicrobial Agents and Chemotherapy.

[5]  A. Ivaska,et al.  Applications of ionic liquids in electrochemical sensors. , 2008, Analytica chimica acta.

[6]  T. Reichenauer,et al.  Free radical processes in green tea polyphenols (GTP) investigated by electron paramagnetic resonance (EPR) spectroscopy. , 2008, Biotechnology annual review.

[7]  O. Fatibello‐Filho,et al.  Flow injection spectrophotometric determination of total phenols using a crude extract of sweet potato root (Ipomoea batatas (L.) Lam.) as enzymatic source , 1998 .

[8]  A. M. Brett,et al.  Catechin electrochemical oxidation mechanisms , 2004 .

[9]  Yibin Ying,et al.  Copper oxide nanoparticles and ionic liquid modified carbon electrode for the non-enzymatic electrochemical sensing of hydrogen peroxide , 2010 .

[10]  H N Graham,et al.  Green tea composition, consumption, and polyphenol chemistry. , 1992, Preventive medicine.

[11]  Xingyi Huang,et al.  Simultaneous determination of total polyphenols and caffeine contents of green tea by near-infrared reflectance spectroscopy , 2006 .

[12]  D. Zheng,et al.  Adsorptive Stripping Voltammetric Detection of Tea Polyphenols at Multiwalled Carbon Nanotubes-Chitosan Composite Electrode , 2009 .

[13]  Joseph Wang,et al.  Carbon nanotube/teflon composite electrochemical sensors and biosensors. , 2003, Analytical chemistry.

[14]  Frieder W. Scheller,et al.  Amperometric biosensor based on a functionalized gold electrode for the detection of antioxidants. , 2002, Biosensors & bioelectronics.

[15]  Y. Ying,et al.  Evaluation of trace heavy metal levels in soil samples using an ionic liquid modified carbon paste electrode. , 2011, Journal of agricultural and food chemistry.

[16]  Z. Apostolides,et al.  Simultaneous analysis of tea catechins, caffeine, gallic acid, theanine and ascorbic acid by micellar electrokinetic capillary chromatography. , 2000, Journal of chromatography. A.

[17]  Richard G Compton,et al.  Carbon nanotube-ionic liquid composite sensors and biosensors. , 2009, Analytical chemistry.

[18]  R. Lamuela-Raventós,et al.  Analysis of total phenols and other oxidation substrates and antioxidants by means of Folin-Ciocalteu reagent , 1999 .

[19]  J. Justin Gooding,et al.  Nanostructuring electrodes with carbon nanotubes: A review on electrochemistry and applications for sensing , 2005 .

[20]  Yibin Ying,et al.  Development of an ionic liquid modified screen-printed graphite electrode and its sensing in determination of dopamine , 2010 .

[21]  Ming Zhou,et al.  Electrochemical behavior of L-cysteine and its detection at ordered mesoporous carbon-modified glassy carbon electrode. , 2007, Analytical chemistry.

[22]  K Umegaki,et al.  Tea catechins prevent the development of atherosclerosis in apoprotein E-deficient mice. , 2001, The Journal of nutrition.

[23]  M. Šeruga,et al.  Electrochemical Characterization of Epigallocatechin Gallate Using Square-Wave Voltammetry , 2009 .

[24]  L. Bazinet,et al.  Catechin stability of EGC- and EGCG-enriched tea drinks produced by a two-step extraction procedure , 2008 .

[25]  Xiao-gang Wang,et al.  Fast detection of catechin in tea beverage using a poly-aspartic acid film based sensor , 2010 .

[26]  Haoqing Hou,et al.  Highly sensitive composite electrode based on electrospun carbon nanofibers and ionic liquid , 2010 .

[27]  M. Miwa,et al.  Platelet aggregation inhibitors in hot water extract of green tea. , 1990, Chemical & pharmaceutical bulletin.

[28]  C. M. Li,et al.  Ionic liquid–graphene composite for ultratrace explosive trinitrotoluene detection , 2010 .

[29]  M. Pumera,et al.  New materials for electrochemical sensing VI: Carbon nanotubes , 2005 .

[30]  Federica Valentini,et al.  Single-wall carbon nanotube paste electrodes: A comparison with carbon paste, platinum and glassy carbon electrodes via cyclic voltammetric data , 2004 .

[31]  S. Dong,et al.  The characteristics of highly ordered mesoporous carbons as electrode material for electrochemical sensing as compared with carbon nanotubes , 2008 .

[32]  Kelly E Heim,et al.  Flavonoid antioxidants: chemistry, metabolism and structure-activity relationships. , 2002, The Journal of nutritional biochemistry.

[33]  Huafu Wang,et al.  Tea flavonoids: their functions, utilisation and analysis , 2000 .

[34]  G. Rivas,et al.  Carbon nanotubes paste electrodes as new detectors for capillary electrophoresis , 2005 .

[35]  Ming Zhou,et al.  Bioelectrochemical interface engineering: toward the fabrication of electrochemical biosensors, biofuel cells, and self-powered logic biosensors. , 2011, Accounts of chemical research.

[36]  Y. Zuo,et al.  Simultaneous determination of catechins, caffeine and gallic acids in green, Oolong, black and pu-erh teas using HPLC with a photodiode array detector. , 2002, Talanta.

[37]  Ming Zhou,et al.  Highly ordered mesoporous carbons as electrode material for the construction of electrochemical dehydrogenase- and oxidase-based biosensors. , 2008, Biosensors & bioelectronics.

[38]  Ming Zhou,et al.  Electrochemical sensing platform based on the highly ordered mesoporous carbon-fullerene system. , 2008, Analytical chemistry.

[39]  Xiuhua Zhang,et al.  Electrochemical properties of catechin at a single-walled carbon nanotubes-cetylramethylammonium bromide modified electrode. , 2009, Bioelectrochemistry.

[40]  Tsukasa Torimoto,et al.  New Frontiers in Materials Science Opened by Ionic Liquids , 2010, Advanced materials.

[41]  S. Dong,et al.  Electrochemical sensing and biosensing platform based on chemically reduced graphene oxide. , 2009, Analytical chemistry.

[42]  Gow-Chin Yen,et al.  Antioxidant activity of various tea extracts in relation to their antimutagenicity , 1995 .