Premium
Fast atom bombardment (FAB) mass spectrometry of piperidine N ‐oxide derivatives and free radical quenching under FAB conditions
Author(s) -
Yan Lin,
Fang Yiwei,
Fang Min,
Zhu Lizhi,
Shen Dekang,
Liang Xiyun
Publication year - 1989
Publication title -
organic mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 0030-493X
DOI - 10.1002/oms.1210240503
Subject(s) - fast atom bombardment , chemistry , mass spectrum , ion , quenching (fluorescence) , radical , mass spectrometry , analytical chemistry (journal) , ionization , electron ionization , piperidine , photochemistry , organic chemistry , fluorescence , chromatography , physics , quantum mechanics
Abstract Mechanisms are proposed for the formation of M + , [M + 2H] + and [M + 3H] + ions in the fast atom bombardment (FAB) mass spectra of 4‐(2,2,6,6‐tetramethyl‐1‐oxyl)‐piperidol and its carboxylates. Free radical quenching induced by the fast atom beam has been observed. The effects of temperature on the radical quenching and of acid on the FAB mass spectra are discussed. The experiment showed that the volatile liquid samples with vapour pressures higher than that for glycerol produced M + even‐electron molecular ions, and the FAB mass spectra were similar to the corresponding electron ionization mass spectra. For the solid samples, it was found that the free radicals were quenched during the FAB process so that the mononitroxide and dinitroxide compounds produced [M + 2H] + and [M + 3H] + ions, respectively. Further experiments showed that the intensities and stabilities of [M + 2H] + and [M + 3H] + ions could be improved by addition of acids.