PYROLYSIS-GAS CHROMATOGRAPHY ION-TRAP DETECTION OF POLYPHENOLS (VEGETABLE TANNINS) - PRELIMINARY-RESULTS

Tannins from sorghum grains with high and low tannin content, from grape skins and seeds and from apple pomace were analysed by pyrolysis/gas chromatography/ion-trap detector mass spectrometry. Pyrolysis at 600-degrees-C produced catechol as a characteristic fragment of condensed tannins, and other phenolic compounds related to the lignified tissues. Catechol was also the main fragment in the pyrogram of catechin, a monomeric constitutent of condensed tannins. Mass spectral data and relative quantifications of the pyrograms of several samples are provided. Quantitative data are discussed in terms of reproducibility and linearity of response and are compared with the results of a spectrophotometric assay for tannins.