SIMULTANEOUS DETERMINATION OF CAFFEINE AND CATECHINS IN TEA EXTRACTS BY HPLC

A simple, rapid, and precise HPLC method was developed for the separation and quantification of catechins and caffeine in green tea extracts. Employing a Hypersil ODS C18 column (150 × 4.0 mm) and a diode UV detector (280 nm), it was found that a satisfactory separation can be achieved by a proper gradient elution using methanol and 0.2% acetonitrile solution. Five catechins (epigallocatechin (EGC), epigallocatechin gallate (EGCG), epicatechin (EC), gallocatechin gallate (GCG) and epicatechin gallate (ECG)) and caffeine in tea extracts were well separated on the chromatogram within 15 min. The method exhibited satisfactory repeatability (RSD ≤1.53%, n = 3) and accuracy (98.7%–102.4%, RSD ≤ 3.50%, n = 3), and reached a simultaneous determination of catechins and caffeine when used for a commercial sample of Chinese green tea extracts. This HPLC method might be suitable for the quality assurance of tea products and catechin-containing preparations.