Determination of anti-carcinogenic polyphenols present in green tea using capillary electrophoresis coupled to a flow injection system

A capillary electrophoresis (CE) method was developed for the simultaneous determination of a number of major ingredients of green tea. The components analysed were caffeine, adenine, theophylline, epigallocatechin-3 gallate, epigallocatechin, epicatechin-3 gallate, (-)-epicatechin, (+)-catechin, ga llic acid, quercetin and caffeic acid. Separation was achieved using a fuse d capillary column with 0.15 M H3BO3 as buffer at a pH of 8.5, UV detection at 210 nm and 20 kV of voltage. Analysis was carried out after treatment ( extraction, filtration and dilution) of the samples in. flow injection syst em which was coupled to a CE equipment via a programmable arm. The procedur e allows the determination of these compounds in less than 20 min. Quantita tive analysis was performed by the standard addition method. Limits of dete ction ranged between 0.04 mu g ml(-1) for flavonols and 1.2 mu g ml(-1) for caffeine. (C) 1998 Elsevier Science B.V. All rights reserved