Some Studies on Mass Spectrometry of Organic Compounds

Borhani, Rahmatollah (1975) Some Studies on Mass Spectrometry of Organic Compounds. PhD thesis, University of Glasgow.

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Abstract

The present thesis contains five chapters: 1. The historical development of mass spectrometry and the theory of various designs of instrumentation are discussed. 2. This chapter records the synthesis of a series of alcohols, acids, and iodides (C5-C7) enriched with 13C at C-1. The mass spectra of these nine compounds have been obtained and compared for the more abundant ions with those of the normal mass spectra obtained from the unenriched molecules. The characteristic fragmentation pathways of these compounds were clarified. The importance of beta-cleavages to the other bonds are emphasised. No evidence was obtained to support the rupture of a 13C-12C bond prior to beta-cleavage, although this bond is weaker than the C-C bond. 3. Chapter three reports the synthesis and interpretation of the mass spectra of some heterocyclic compounds with special emphasis on rearrangement processes. Some comments upon the McLafferty rearrangement are reported. Attempts were made, without success, to replace sulphur firstly by selenium and then by tellurium in the synthesis of thioamides. 4. The fourth chapter discusses a computer matching technique for the identification of organic compounds. Programmes have been developed to compare the unknown spectrum with the library file without using the molecular weight of the compound. A successful result was obtained after each search. 5. In this chapter the analysis of unknown mixtures by mass spectrometry is described. The use of high resolution mass spectrometry clarified the occurrence of certain synthetic reactions in the source of mass spectrometer. In this investigation the composition of fifteen extra compounds and also ten protonated ions, induced by electron impact of a four component mixture, are reported. From the results obtained it is concluded that the analysis of mixtures by mass spectrometry may not always be an efficient technique, particularly when the mixture contains sulphur compounds.

Item Type: Thesis (PhD)
Qualification Level: Doctoral
Keywords: Organic chemistry, Analytical chemistry
Date of Award: 1975
Depositing User: Enlighten Team
Unique ID: glathesis:1975-78710
Copyright: Copyright of this thesis is held by the author.
Date Deposited: 30 Jan 2020 15:00
Last Modified: 30 Jan 2020 15:00
URI: http://theses.gla.ac.uk/id/eprint/78710

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