Rapid, direct determination of polyphenols in tea by reversed-phase columnliquid chromatography

Column liquid chromatography on a C-18-bonded silica column with water-meth anol-acetic acid as eluent was used to determine polyphenols and caffeine i n tea. Without any pretreatment, catechin, epicatechin gallate, epigallocat echin gallate, epigallocatechin, epicatechin and caffeine were separated su ccessfully within 15 min. The detection limits (S/N=3) of polyphenols studi ed were 1.8-24 mg/l at a detection wavelength 270 nm. The linear range of t he peak area calibration curves for the analytes were over two orders of ma gnitude with a correlation coefficient of 0.996-0.999. Using this method, s ome Chinese tea samples were analyzed with a good reproducibility (RSD are below 5%). (C) 1999 Elsevier Science B.V. All rights reserved.