Determination of Theaflavines in Black Tea by High-Performance Liquid Chromatography

Abstract

A high-performance liquid chromatographic (HPLC) method to determine theaflavines in black tea was investigated. An assay solution was prepared as follows: Zero point six mg of purpurogallin was added to 1g of black tea, and the theaflavines were extracted with 50ml of 40% (v/v) acetone for 30min at room temperature. The extract was filled up to 100ml with water and centrifuged at 3000rpm for 5min. The supernatant was filtered with 0.45μm filter, and 90μl of the filtrate was injected to HPLC. A column (4.6mmφ× 25cm) was packed with ODS-120 A (10μm, Toyo-soda) and eluted with water-acetonephosphoric acid (385:110:1.5, v/v) at a flow rate of 1.0ml/min. Column effluents were monitored by UV-visible detector set at 375nm. This method will ensure the deteremination of theaflavines in black tea with 3.304.20% of coefficients of varience and 91.1-96.0% of recovery.