Rapid method for measuring thearubigins and theaflavins in black tea using C₁₈ sorbent cartridges

This communication describes the routine use of small inexpensive C 18 cartridges for rapid separation and accurate measurement of both thearubigins (TR) and theaflavins (TF) in a liquor brewed from black tea. The slow, traditional method overestimates TR content because of interference from flavonol glycosides. Comparison is also made favourably with other methods available for estimating total TF and sometimes TR in tea.