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Routes of Formation and Decomposition of the m / z 59 Ions with Elemental Composition C 3 H 7 O Generated upon Electron Impact Ionization of Methyl Propanoate
Author(s) -
Sekiguchi Osamu,
Aoyagi Kenichi,
Tajima Susumu,
Nibbering Nico M. M.
Publication year - 1997
Publication title -
journal of mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 1076-5174
DOI - 10.1002/(sici)1096-9888(199707)32:7<755::aid-jms528>3.0.co;2-g
Subject(s) - chemistry , ion , electron ionization , microsecond , mass spectrum , deuterium , ionization , analytical chemistry (journal) , mass spectrometry , decomposition , atomic physics , organic chemistry , physics , chromatography , astronomy
It is shown that the peaks at m / z 31, 29 and 15 in the mass‐analyzed ion kinetic energy spectrum of the m / z 59 ions generated from methyl propanoate upon electron impact ionization originate from decompositions of m / z 59, i.e. C 2 H 3 O 2 + ions having the O = C = O + CH 3 structure, and of m / z 59, i.e. C 3 H 7 O + ions having the CH 3 CH = O + CH 3 structure. The latter ions contribute <1% to the total abundance of the m / z 59 ions in the standard mass spectrum. However, these m / z 59 C 3 H 7 O + ions are responsible for the relatively significant amounts of the m / z 31 and 29 ions generated in the microsecond time frame. Based upon deuterium labelling and supported by calculations at the ROHF/6–31G* level of theory, the m / z 59 C 3 H 7 O + ions are suggested to be formed via a complex skeletal rearrangement of the molecular ions of methyl propanoate and subsequent loss of a formyl radical. © 1997 by John Wiley & Sons Ltd.