Mass spectrometry of monotrimethylsilylated flavonoid methy ethers

Monotrimethylsilyated flavonoid methyl ethers were studied with electron impact mass spectrometry, and derived from natural compounds by methylation, hydrolysis and trimethylsilylation. Spectra were compared with those of the permethylated flavonoid. Fragment ions were distinguished among the various types; the [M  15]+ ion for 3-O-trimethylsilyated flavonoid methyl ethers, the [M  72]+. ion for 5-O-trimethylsilylated flavonoid methyl ethers, the M+., [M  1]+ and [M  TMSiO]+ ions for 7-O-trimethylsiylated flavonoid methyl ethers and 3′- or 4′-O-trimethylsilylated flavonoid methyl ethers and the [M  19]+ ion for 3,5-di-O-methylflavonoids. Further, fragmentation mechanisms and their differences were examined with the aid of labelled compounds and relative compounds of the trimethylsilyl group.