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|Title:||Selected studies in fast atom bombardment mass spectrometry|
|Author(s):||Proefke, Mark L.|
|Doctoral Committee Chair(s):||Rinehart, Kenneth L., Jr.|
|Department / Program:||Chemistry, Analytical|
|Degree Granting Institution:||University of Illinois at Urbana-Champaign|
|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.
|Rights Information:||Copyright 1992 Proefke, Mark L.|
|Date Available in IDEALS:||2011-05-07|
|Identifier in Online Catalog:||AAI9215872|