Formation of the [M+NH_4]^+ Ious of Some Mouo-and Di-saccharides in Fast Atom Bombardment Mass Spectrometry

In positive-ion fast atom bombardment (FAB) mass spectrometry, when mono- and di- saccharides are mixed with an appropriate amount of NH4Cl, a highly abundan peak [M+NH4]+appers in FAB mass spectra . From the adduct ion [M+NH4]+, the molecular weights of mono- and di- saccharides can be determined definitively

Stereochemical effects in mass spectrometry——Ⅺ.Negative ion fast atom bombardment mass spectrometry of saccharides and glycosides using phenylboronic acid as reagent

The negative ion fast atom bombardment (NIFAB) mass spectra of mono-,di-saccharides and glycosides using phenylboronic acid (PBA) as reagent have been studied.In the ion source,PBA reacts stereospecifically with the molecules containing cis-vicinal glycols to form characteristic ions, from which the stereo-isomers of saccharides can be definitely distinguished.Disaccharides and glyco- sides with β-glycosidic linkage seem to be unfavorabale to react with PBA,therefore,by comparison of the abundances of the characteristic ions,the configuration of the glycosidic linkage in these compounds may be inferred.