Mass spectrometric methods for the characterisation and differentiation of isomeric O ‐diglycosyl flavonoids

Abstract Tandem mass spectrometric methods have been evaluated for the characterisation of the type and the differentiation of the interglycosidic linkage of isomeric flavonoid O ‐diglycosides. Based on the occurrence of internal monosaccharide residue loss and the relative abundances of Y‐type ions formed by fragmentation at glycosidic bonds, four pairs of isomeric flavonoid O ‐diglycosides can be unambiguously differentiated. The different techniques used, i.e. linked scanning at constant B/E without collisional activation and low‐energy collision‐induced dissociation using methane or helium as collision gas, have been shown to be useful for distinguishing the two most common (1, 2‐ and 1, 6‐) interglycosidic linkages, e.g. flavonoid O ‐neohesperidosides and O ‐rutinosides. Copyright © 2001 John Wiley & Sons, Ltd.