Determination of condensed tannin monomers in environmental samples by capillary gas chromatography of acid depolymerization extracts

A method for molecular-level quantification of condensed tannin is describe d that uses acid depolymerization and carbocation capture by phloroglucinol . Resulting monomers and phloroglucinol adducts are trimethylsilyl derivati zed, separated by capillary gas chromatography, detected by name ionization , and quantified relative to standards. Optimal depolymerization conditions were determined for acid strength, phloroglucinol concentration, time, and temperature. The method gives reproducible results in leaf litter that are linear over 2 orders of magnitude with detection limits down to similar to 100 ng condensed tannin, In addition to tannin, triterpenoids were also id entified and can be quantified with this method. Analyses of soils and sedi ments indicate that mineral interactions with condensed tannin are importan t both analytically and environmentally.