Different alternatives for the determination of tannins in tea with Cu ionspecific electrodes and atomic absorption spectrometry are discussed. The methods are based on the precipitation of tannins with copper acetate. A screening of methods is carried out in three successive steps: determination of (1) Cu in a simple aqueous solution, (2) tannic acid in aqueous solution and (3) tannins in tea. Two procedures are proposed as suitable tools for tannin determination in tea, i.e. direct potentiometry of excess Cu2+ and AAS, the first being the easiest and most rapid. © 1979 Springer-Verlag.
