Analysis of oak tannins by liquid chromatography-electrospray ionisation mass spectrometry

Extractable tannins were analysed by liquid chromatography-electrospray ion isation mass spectrometry in two oak species, North American white oak (Que rcus alba) and European red oak (Quercus robur). They mainly included vario us glucose gallic and ellagic acid esters. The structures were partially de termined, and they included grandinin/roburin E, castalagin/vescalagin, gal lic acid, valoneic acid bilactone, monogalloyl glucose, digalloyl glucose, trigalloyl glucose, ellagic acid rhamnose, quercitrin and ellagic acid. (C) 2000 Elsevier Science BN: All rights reserved.