Linear quadrupole ion trap (LQIT) and laser-induced acoustic desorption (LIAD) instrumentation and methods developlement for direct strucutural elucidation of components in complex mixtures
Abstract
Mass spectrometry has been widely proven as an invaluable tool for the field of complex mixture analysis and the identification of unknown molecules due to its high sensitivity, selectivity, versatility and speed. In addition, its reliability, reproducibility and its capability of providing information-rich data through the use of tandem mass spectrometric methodologies have revolutionized the analysis of complex mixtures. With the advent of atmospheric pressure ionization (API) techniques, mass spectrometry has transformed the way in which complex mixture analysis is performed, expanding the applications of MS to various nonvolatile and thermally labile substrates. In addition, the integration of tandem mass spectrometry (MSn) experiments like collision-activated dissociation (CAD) and ion/molecule (I/M) reactions to most mass spectrometers has rendered these techniques as standards for the structural elucidation of components in complex mixtures. Also, API methods allow for the facile integration of MS with high-performance liquid chromatography (HPLC), thus allowing for the fast separation of these mixtures prior to tandem MS analysis. However, techniques such as this do not always result in the unambiguous identification of unknown components. This thesis focuses on the development of ionization techniques, novel instrumentation, HPLC methods and tandem mass spectrometric methodologies to allow for the unambiguous identification of unknown compounds in complex mixtures. In addition, laser-induced acoustic desorption (LIAD) is investigated for its use with commercial mass spectrometers for the analysis of molecules currently not amenable to commercially available ionization techniques and instrumentation. Since the introduction of LIAD, it has been proven to be a powerful method for the evaporation of a wide variety of nonvolatile and thermally labile compounds, as well as complex mixtures wherein the composition is extremely varied. Finally, a novel and powerful mass spectrometer is proposed and described in this thesis. This instrument allows for CAD experiments and (I/M) reactions to be performed in tandem without their interference, thus resulting in one of the most versatile mass spectrometers to date. This instrument is likely to prove invaluable for the analysis of complex mixtures and the identification of unknown components in complex mixtures.
Degree
Ph.D.
Advisors
Kenttamaa, Purdue University.
Subject Area
Analytical chemistry
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