Determination of theaflavin in tea liquors using voltammetric methods

Abstract

Voltammetric methods can be used to determine theaflavins in tea liquors. Differential-pulse polarography and linear scan voltammetry on a hanging mercury drop electrode have been shown to be effective. The only sample treatment step required is a simple dilution using an acetate buffer solution (pH 4–5). Well defined polarograms were obtained from 5 ml of a tea extract (2%m/V) diluted to 25 ml with a final buffer concentration of around 0.1 M. Differential-pulse polarograms show two pH dependent peaks in the vicinity of –1.0 V vs. SCE. The more positive peak was identified as arising from theaflavin. As the separation of theaflavin is not necessary these techniques offer several advantages over the conventional flavognost test.