Greathead, Roger Julian (1982) Structural applications of gas phase ion-molecule reactions. PhD thesis, University of Warwick.

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Abstract

A variety of mass spectrometers have been used to study four projects, involving three different applications of gas phase ion- molecule reactions. Firstly, the use of the vinyl methyl ether radical cation for the location of olefinic bonds (NEUTRAL STRUCTURE DETERMINATION) has been improved by altering the mode of production of the reagent ion. The scope and application of this technique have been reviewed.

Secondly, the structures of various C3H6O† and C4H5N+ ions (ION STRUCTURE DETERMINATION) have been studied.
Reactions specific for the structures (i) CH3-O-CH-CH2ﬧ+ and (ii)CH2=O+-CH2-CH2 have been identified and employed to detect the presence of C3H6O+‘ ions of these structures formed from a variety of precursors. These results provide an insight into the mechanisms of sane gas phase elimination reactions and allow this method to be compared with those providing analogous information. Reactions have been sought to characterise the structure of C4H3N+ ions generated from five different neutral precursors. Such reactions proved not to be identifiable readily, with the exception of a reaction involving 1.3-butadiene which appears to be specific for the pyrrole molecular ion structure. Finally, the beginning of the application of the technique of Mass Spectrometry/Mass Spectrometry to the detection of gibberellins in mixtures (MIXTURE ANALYSIS) is described.

The results of a survey of the chemical ionisation of the gibberellins are presented. The collision induced decomposition spectra of nine gibberellin/ammonium adduct ions are reported, showing that this method is capable of distinguishing readily all these gibberellins, some of which are isomers. Preliminary results involving crude grass extracts spiked with gibberellins are presented and methods of lowering the detection levels obtained have been suggested. Evidence concerning the pyrolysis of gibberellic acid is presented and discussed. These experiments and results serve to illustrate the varied use of gas phase ion-molecule reactions in structure determination.

Item Type:	Thesis (PhD)
Subjects:	Q Science > QC Physics Q Science > QD Chemistry
Library of Congress Subject Headings (LCSH):	Ionized gases, Chemical reaction, Conditions and laws of, Ion-molecule collisions, Mass spectrometry
Official Date:	April 1982
Dates:	Date Event April 1982 UNSPECIFIED
Institution:	University of Warwick
Theses Department:	Department of Chemistry
Thesis Type:	PhD
Publication Status:	Unpublished
Supervisor(s)/Advisor:	Jennings, Keith R., 1932
Sponsors:	Science Research Council (Great Britain) ; Shell Research Ltd. Sittingbourne Research Centre
Format of File:	pdf
Extent:	xv, 170 leaves : illustrations
Language:	eng

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