Analysis of Oligomeric and Polymeric Tannins of Grape Berries by Liquid Chromatography/Electrospray Ionization Multiple-Stage Tandem Mass Spectrometry

Abstract

Tannins are highly polar, water-soluble and thermally-labile compounds which are difficult to ionize. Mass spectrometry is very useful for the structural determination of such compounds. In this article, we describe a sensitive method for the identification of tannic composition in grape berries (var. Gamaret). An ion trap, equipped with an electrospray ionization (ESI) interface, allowed us to develop multiple-stage fragmentation (MS n ), which provided useful structural information. This technique was applied to a mixture of proanthocyanidins and proanthocyanidin gallate oligomers (B-type) generating identical ion sequences for each parent ion.