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The [C 5 H 8 ] + ˙ radical cation: Structural studies by energy‐resolved mass spectrometry
Author(s) -
Mason R. S.,
Jennings K. R.,
Verma S.,
Cooks R. G.
Publication year - 1985
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.1210201206
Subject(s) - ion , dissociation (chemistry) , chemistry , atomic physics , mass spectrometry , collision , excitation , spectral line , collision induced dissociation , mass spectrum , ionization , range (aeronautics) , analytical chemistry (journal) , physics , materials science , tandem mass spectrometry , computer security , organic chemistry , chromatography , quantum mechanics , astronomy , computer science , composite material
Control of the degree of collisional excitation of an ion can be achieved by varying the collision energy or the number of collisions. The former experiment yields a series of daughter spectra which is analogous to a breakdown curve and which serves to characterize the ion undergoing collisionally activated dissociation (CAD). Recognition of differences in the spectra between isomeric ions is facilitated if the curves obtained from the energy‐resolved data are considered in pairs and their differences are plotted. This procedure serves to demonstrate that ionized 1,3‐ and 1,4‐pentadiene are structurally distinct, even though they are not distinguishable in conventional CAD. 2‐Pentyne and 3‐octyne give [C 5 H 8 ] + ˙ fragment ions which are closely related to the 1,3‐ and 1,4‐pentadiene structures, respectively. Any particular ion can be characterized by another form of difference spectrum: one comparing data at two collision pressures each taken over a range of collision energies. This procedure yields conclusions regarding ion structure which match those reached from the energy‐resolved experiments.