Positive ion FAB mass spectra of prenylated flavonoids were compared with the corresponding EI and CI mass spectra, and some fragment ions similar to those in the EI mass spectra and CI-like intense protonated molecules (M+H)+ were recognized. Major fragmentations in the EI and FAB mass spectra were discussed. It was concluded that FAB ionization possesses both features, EI-like hard ionization and CI-like soft ionization.
