RP-HPLC Determination of Catechinic Compounds and Caffeine in Tea Drinks

RP-HPLC was applied to the determination of caffeine (CAF) and 5 catechinic compounds, namely: catechin (C), epicatechin (EC), epigallocatechin gallate (EGCG), epicatechin gallate (ECG) and epigallocatechin (EGC), in tea drinks. The 6 components were separated on the TC-C18 column (4.6 mm×250 mm, 5 μm) by elution with a mixture of methanol-acetonitrile-acetic acid-water (230+60+2+708) as mobile phase. Flow-rate of the mobile phase was set at 1.0 mL·min-1, and UV-detection at 210 nm was adopted in the determination. Standard curves of the 6 components were prepared by using the respective standard solutions, and linear regression equations with correlation coefficients from 0.9998 to 0.9999 were obtained. The proposed method was applied to the analysis of tea drinks, giving values of recovery obtained by standard addition method in the range of 86.6%-118.1% and RSD′s (n=6) in the range of 0.74%-3.4%.