Abstract
HPLC-FTIR was investigated for the qualitative determination of catechins and methyl xanthines present in green tea extracts. A reversed phase separation of the green tea components was performed on a C-18 column equilibrated at 30°C using an isocratic mobile phase of acetonitrile: 0.1% formic acid (15 : 85), prior to introduction to the deposition interface linked to the FTIR detector. The solvent was evaporated at 130°C and spectra were collected every six seconds during the run. Six catechins, (+)-catechin, gallocatechin, (−)-epicatechin, (−)-epigallocatechin and (−)-epigallocatechin gallate, and (−)- epicatechin" gallate, as well as two methyl xanthines, caffeine and theobromine, were separated and positively identified in a sample of Chinese green tea. The catechins and methyl xanthines were matched to the respective standards by both retention time and the measured infrared spectrum.