Selected studies in fast atom bombardment mass spectrometry
Proefke, Mark L.
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Permalink
https://hdl.handle.net/2142/23619
Description
Title
Selected studies in fast atom bombardment mass spectrometry
Author(s)
Proefke, Mark L.
Issue Date
1992
Doctoral Committee Chair(s)
Rinehart, Kenneth L., Jr.
Department of Study
Chemistry, Analytical
Discipline
Chemistry, Analytical
Degree Granting Institution
University of Illinois at Urbana-Champaign
Degree Name
Ph.D.
Degree Level
Dissertation
Keyword(s)
Chemistry, Analytical
Language
eng
Abstract
Two methods of enhancing positive ion yields in fast atom bombardment mass spectrometry (FABMS) were investigated. In one set of experiments, chemical ionization was combined with fast atom bombardment to enhance positive ion yields in FABMS. These experiments showed enhancements of over three orders of magnitude in ion currents for simple matrices. However, when extended to typical FAB systems, disproportionate enhancements in the matrix versus sample signals were observed. An additional set of experiments looked at enhancing FAB ion yields using laser irradiation. Although inadequate photon fluxes were available to photoionize the desorbed neutral species above the target, enhancements in signal intensity and fragment ion formation were observed when the laser irradiation was deposited directly into the FAB droplet on the target.
Recent efforts in coupling gradient liquid chromatography (LC) with FABMS using a moving belt interface were also described. A new depositor containing an integral heater and feedback control was constructed. Characterization of this system along with experimental data showing its utility with gradient LC separations of peptiabophol antibiotics and countercurrent chromatography was presented.
Finally, two applications demonstrating the power of FABMS to solve complicated structural problems were presented. In the first example, a novel neuropeptide isolated from the stick insect Carausius morosus was sequenced by tandem FABMS and GC/MS. Research up to this point indicates that a hexose may be attached to the tryptophan unit of this peptide. In the second example, the principal components of an Egyptian mummy resin were determined by FABMS. Several oxidation products of abietic acid identified the resin base as a pine pitch. In addition, the presence of several n-alkanes along with characteristic trace metals confirmed the addition of bitumen to the embalming fluid.
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