Characterization of flavone and flavonol aglycones by collision-induced dissociation tandem mass spectrometry

A mass spectrometric method based on the combined use of fast atom bombardment collisionally-induced dissociation (CID) and tandem mass spectrometry has been used for the structural characterization of free and conjugated flavone and flavonol aglycones. Low-energy CID spectra of the [M + H]+ (or Y+0) ions show simple fragmentation patterns, which allow characterization of the substituents in the A and B rings and, in particular, differentiation between flavones and flavonols. A systematic nomenclature for product ions produced from protonated molecules under CID conditions is proposed. © 1997 John Wiley & Sons, Ltd.