Estimation of theaflavins in tea by gas—liquid chromatography of their trimethylsilyl ethers

Abstract A method for separating and estimating the theaflavins of tea by temperature-programmed gas—liquid chromatography of their trimethylsilyl ethers is described. 6-in. columns of 3 % OV-1 on Chromosorb W separate theaflavin from its two monogallates and its digallate, and used with a 1,3-distearin standard, give results reproducible to within ± 5 %. Fractions suitable for analysis are obtained by chromatography of ethyl acetate extracts of whole tea solubles on Sephadex LH-20. This method gives lower results than R oberts' spectrophotometric method: chromatograms of acetate extracts before and after bicarbonate extraction suggest that this is a result of incomplete extraction of thearubigins in the R oberts' method.