Simultaneous determination of catechins, caffeine and gallic acids in green, oolong, black and pu-erh teas using HPLC with a photodiode array detector

Yuegang Zuo, Hao Chen, Yiwei Deng

Research output: Contribution to journalArticlepeer-review

492 Scopus citations

Abstract

A simple and fast HPLC method using a photodiode array detector was developed for simultaneous determination of four major catechins, gallic acid and caffeine. After multiple extractions with aqueous methanol and acidic methanol solutions, tea extract was separated within 20 min using a methanol-acetate-water buffer gradient elution system on a C18 column. The sample extraction data demonstrated that the single extraction used in the previous studies with aqueous acetonitrile or methanol is not sufficient; the multiple extraction procedure is essential for the quantitative analysis of catechins, phenolic acids and caffeine in teas. Several green, Oolong, black and pu-erh teas were successfully analyzed by this method. The analytical results obtained indicated that green teas contain higher content of catechins [(-)-epigallocatechin gallate, (-)-epigallocatechin, (-)-epicatechin gallate, and (-)-epicatechin] than both Oolong, pu-erh and black teas because fermentation process during the tea manufacturing reduced the levels of catechins significantly. The fermentation process also remarkably elevated the levels of gallic acid in full-fermented pu-erh and black teas. Another interesting finding is the low level of caffeine in Oolong teas, especially in Fujian Oolong tea.

Original languageEnglish (US)
Pages (from-to)307-316
Number of pages10
JournalTalanta
Volume57
Issue number2
DOIs
StatePublished - May 16 2002
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Analytical Chemistry

Keywords

  • Black tea
  • Caffeine
  • Catechins
  • Flavonoids
  • Gallic acid
  • Gradient HPLC
  • Green tea
  • Oolong tea
  • Polyphenols
  • Pu-erh tea

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