Abstract
Proanthocyanidins (PAC) show high degree of isomerism, which makes it difficult to confirm the identification of new congeners. A novel class of PAC with a macro-cyclic structure has been recently found in wine[1, 2]. Hydrogen/deuterium isotopic exchange (HDX) combined to high resolution MS is discussed for the disambiguation of such cyclic B-type class from other isomeric PAC present in wine and other significant dietary sources.