title: Comprehensive study of condensed tannins by ESI mass spectrometry: average degree of polymerisation and polymer distribution determination from mass spectra.
abstract: The determination of the molecular mass distribution of tannins is still a challenge. To elucidate it, mass spectrometry is potentially interesting, but many previous studies have highlighted that the mass spectra of a tannin fraction do not always reflect the actual abundance of different chain lengths. To clarify the potentialities offered by the MS approach, a comprehensive study involving different tannin fractions analysed under different conditions was conducted with an electrospray ionization (ESI) source. This study allowed optimised ESI-MS conditions to be established for analysing tannins but also it outlines the limits of detection encountered. If the detection of high molecular weight tannins seems difficult or even impossible, the spectral distortions brought about by this limitation are not totally related to the sole average degree of polymerisation of the tannin fraction studied but greatly depend on its polymer distribution. However, ESI-MS used under optimised conditions is a suitable method to study tannin composition of vegetable extracts which contain degree of polymerisations below 26.
authors.affiliation: INRA, UMR1083, 34060 Montpellier, France. moulsl@supagro.inra.fr
authors.forename: Laetitia
authors.initials: L
authors.lastname: Mouls
authors.forename: Jean-Paul
authors.initials: JP
authors.lastname: Mazauric
authors.forename: Nicolas
authors.initials: N
authors.lastname: Sommerer
authors.forename: Hélène
authors.initials: H
authors.lastname: Fulcrand
authors.forename: Gérard
authors.initials: G
authors.lastname: Mazerolles
mesh_terms: D010936:Plant Extracts / Q000737:chemistry*; D058105:Polymerization; D044945:Proanthocyanidins / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D014675:Vegetables / Q000737:chemistry
chemical_list: D010936:Plant Extracts; D044945:Proanthocyanidins