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.

质谱中的立体化学效应15.——单糖甲基苷的热喷雾质谱

本文报道了六种己糖甲基苷和四种戊糖甲基苷的热喷雾质谱,不同构型的差向异构体产生的裂片离子[M+NH_4—H_2O]^+[M+NH_4—2H_2O]^+或[M+NH_4—H_2O—NH_3]^+的相对丰度各不相同,从立体化学的角度讨论了产生这些差别的原因。