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Structural identification of alkene isomers by photodissociation–photoionization mass spectrometry
Author(s) -
Van Bramer Scott E.,
Johnston Murray V.
Publication year - 1992
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.1210270904
Subject(s) - photoionization , photodissociation , chemistry , mass spectrometry , fragmentation (computing) , degree of unsaturation , dissociation (chemistry) , photochemistry , alkene , molecule , mass spectrum , ultraviolet , ionization , ion , organic chemistry , chromatography , physics , quantum mechanics , computer science , operating system , catalysis
Photodissociation‐photoionization, mass spectrometry (PDPI/MS) is used to probe the neutral dissociation chemistry of branched alkenes and dienes. Molecules are photodissociated with an ultraviolet laser and the resulting neutral fragments are subsequently photoionized with coherent vacuum ultraviolet radiation. The neutral fragmen tation observed is useful for characterizing compounds which isomerize prior to ionic fragmentation. Unimolecular photodissociation of dienes and branched alkenes is dominated by cleavage of the β CC bond. In a few cases, α‐cleavage is also observed. When two isomers produce isomass primary products, secondary fragmentation can be used to distinguish the structures. The primary and secondary product distributions are predictable and usually occur without iomerization. As a result, PDPI/MS can be used to determine the sites of branching and unsaturation in small (C 5 –C 8 ) aliphatic compounds.