Extracts of several varieties of tea were separated by HPLC and the resulting substances detected by various techniques with a view to characterizing the fractions of organic metal complexes of copper, zinc, and iron. In addition to uv methods and conductivity measurements particular stress was laid on the application of HPLC coupled with chemical reaction detectors for metals (photometric determination of total content) and for functional groups, such as phenolic OH-, SH-, and NH-groups. The distribution of the different metals was found by coupling HPLC with AAS. The chromatograms obtained permitted the fractions of individual metals to be attributed to the appropriate organic binding forms. With tea, phenolic bonds are important but binding to amino groups could also be shown to exist. The differences between the types of metal binding forms encountered in the varieties of tea investigated are caused by their constituents and/or by their modification brought about by processing.
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