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Title: Development of an orthogonal acceleration time-of-flight mass spectrometer : structural and quantitative applications in mass spectrometry
Author: Williams, C. M.
Awarding Body: University of Wales Swansea
Current Institution: Swansea University
Date of Award: 2004
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This thesis describes the development of a prototype orthogonal acceleration time-of-flight mass spectrometer, constructed at Swansea University (2002). This instrument incorporated design features to improve the duty-cycle of the time-of-flight mass spectrometer and was designed to conduct MS and MS/MS. Ion optical interfaces for full-beam transmission and collision-induced dissociation were developed. This work characterises the transport efficiency of the interfaces with a SCIEX electrosprayer. Ion transmission was dependent on the ion optical configuration, lens voltages, orifice sizes and stagnation pressure. Due to time limitations the full instrument was not completed and experimental work finalised on a commercial time-of-flight. A study of the ion structure of C4H4+ was carried out. A new method relying on consecutive reactions for controlling the internal energy of ions was used. Collision induced dissociation spectra of C4H4+ allowed the composition of the ion beam to be monitored and the vinylacetylene and methylenecylcopropene structures dominated. An observation was made for the fragmentation C4H4+ ® C3+., C3H1+, C3H2+ and C3H3+ for C4H4+. formed in the ion source, compared to C4H4+ formed in a field-free region. Their collision-induced dissociation mass-analysed ion kinetic energy (CID-MIKE) spectra were very different, which could not be accounted for in terms of structural and possibly internal energy differences. This is a highly reproducible effect requiring further study. Matrix-assisted laser desorption/ionisation (MALDI) was used on a ‘Voyager-DE STR’ to develop a survey technique analysis of nucleotides. The matrix α-cyano-4-hydroxyxinnamic acid matrix provided good sensitivity (<10pmol). MALDI as a quantitative tool was investigated. There are major challenges to overcome before MALDI can be reliably used for quantitation of nucleotides. An experimental survey of over 900 accurate mass measurements was made on 10 compounds and showed that accurate masses could be reliably obtained for 40% of adenosine monoshosphate samples but for quanosine di- and triphosphates this fell to near zero.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available