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An Unexpected Effect of the Nature of the Collision Gas in Collisional Activation Mass Spectrometry
Author(s) -
Flammang Robert,
Gallez Laurence,
Van Haverbeke Yves,
Wah Wong Ming,
Wentrup Curt
Publication year - 1996
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/(sici)1097-0231(19960131)10:2<232::aid-rcm471>3.0.co;2-d
Subject(s) - chemistry , mass spectrometry , collision , computational chemistry , chromatography , computer security , computer science
Radical‐cations a–c with the structure HN=C=C=X (X=O, NH, S respectively) have been studied by collisional‐activation (CA) mass spectrometry using different target gases (helium, oxygen and nitrogen). An unusual effect of the nature of the collision gas has been noted for oxygen which induces a very intense loss of a nitrogen atom for ions a and b, but not for ion c. The replacement of the NH hydrogen by a methyl group suppresses this effect. Oxygen therefore appears to induce an isomerization of ions a and b into nitrene isomers a′ and b′ (N—CH=C=X). The use of nitrogen, which gives essentially the same CA spectra as helium, eliminates the possibility of an effect based on the center‐of‐mass collision energy. G2(MP2) calculations indicate that the nitrene radical‐cations lie close in energy to the cumulene ions when X=O or NH.