Abstract:

A high performance liquid chromatographic (HPLC) method was established for the simultaneous determination
of ten components including caffeine, catechin (C), epicatechin (EC), epigallocatechin (EGC), epicatechin gallate (ECG),
epigallocatechin gallate (EGCG), theaflavin (TF1), theaflavin-3-gallate (TF2A), theaflavin-3’-gallate (TF2B), theaflavin-
3,3’-digallate (TF3), in Congou black tea. The chromatographic conditions were optimized. A Whatman Partisphere C18
column (4.6 mm × 125 mm, 5 μm) was used to separate the ten compounds. The mobile phase was a mixture of 0.035%
trifluoroacetic acid containing 5% acetonitrile (A) and 50% acetonitrile solution containing 0.025% trifluoroacetic acid and
methanol solution (B) at a flow rate of 1 mL/min. The column temperature and UV detection wavelength were set as 32 ℃
and 205 nm, respectively. The ten components were successfully separated and detected under the chosen experimental
conditions. The calibration curves for all these components displayed a good linear relationship with correlation coefficients
above 0.999 8 and precision relative standard deviations (RSDs) of 0.72%–3.32% (n = 5) and repeatability RSD of 1.87%–
4.43% (n = 5). The recovery rates of the ten compounds were in the range of 94.73%–102.38%. The method is convenient,
rapid, accurate, reproducible and applicable to simultaneously determine these ten components in Congou black tea.

Key words: Congou black tea, high performance liquid chromatographic (HPLC), components, determination