Davin Martin - Academia.edu (original) (raw)
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King Abdullah University of Science and Technology (KAUST)
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The recent introduction of commercial Atmospheric Pressure PhotoIonization (APPI) sources for use... more The recent introduction of commercial Atmospheric Pressure PhotoIonization (APPI) sources for use on Liquid Chromatography-Mass Spectrometry (LCMS) instruments has expanded the range of analytes that can be analyzed to include non-polar compounds. The two commercial photon sources use a low pressure krypton discharge lamp that selectively ionizes many classes of analytes but not common solvents. This thesis explores two hypotheses; (a) that ionization can be independent of discharge gas type and (b) that vapours of solid samples can be ionized and rapidly analyzed by mass spectrometry. To explore the effect of discharge gas on ionization, a novel atmospheric pressure discharge lamp was constructed. Helium, nitrogen, argon, hydrogen, oxygen, carbon dioxide, and compressed air were evaluated as discharge gases to generate photons that would induce photoionization in naphthalene as a representative polycyclic aromatic hydrocarbon. Photon emission spectra of argon, helium, hydrogen, oxygen and nitrogen were characterized and found to be consistent to reference spectra. Calibration curves were constructed for naphthalene and compared to a calibration curve obtained using a commercial (PhotoMate, Syagen Inc.) photoionization lamp. The custom made discharge lamp was slightly more sensitive and gave mass spectra comparable to the commercial lamp leading to the conclusion that ionization was independent of discharge gas type. iii Under the second objective, an innovative way to introduce vapours from solid samples was developed. Small amounts of solid crystal sample were heated to produce vapours that were then photoionized. Mass spectra were collected on a number of polycyclic aromatic compounds and metal containing organic compounds. Collision induced dissociation was used to characterize specific analytes of interest. The ability to use a variety of discharge gases for photoionization lowers the cost of construction and improves the ruggedness of photoionization ionization sources. The ability to quickly characterize solid samples has a range of applications including rapid confirmation of synthetic chemistry reactions, quality assurance in pharmaceutical production, detection of drugs of abuse and detection of chemical warfare agents.
The recent introduction of commercial Atmospheric Pressure PhotoIonization (APPI) sources for use... more The recent introduction of commercial Atmospheric Pressure PhotoIonization (APPI) sources for use on Liquid Chromatography-Mass Spectrometry (LCMS) instruments has expanded the range of analytes that can be analyzed to include non-polar compounds. The two commercial photon sources use a low pressure krypton discharge lamp that selectively ionizes many classes of analytes but not common solvents. This thesis explores two hypotheses; (a) that ionization can be independent of discharge gas type and (b) that vapours of solid samples can be ionized and rapidly analyzed by mass spectrometry. To explore the effect of discharge gas on ionization, a novel atmospheric pressure discharge lamp was constructed. Helium, nitrogen, argon, hydrogen, oxygen, carbon dioxide, and compressed air were evaluated as discharge gases to generate photons that would induce photoionization in naphthalene as a representative polycyclic aromatic hydrocarbon. Photon emission spectra of argon, helium, hydrogen, oxygen and nitrogen were characterized and found to be consistent to reference spectra. Calibration curves were constructed for naphthalene and compared to a calibration curve obtained using a commercial (PhotoMate, Syagen Inc.) photoionization lamp. The custom made discharge lamp was slightly more sensitive and gave mass spectra comparable to the commercial lamp leading to the conclusion that ionization was independent of discharge gas type. iii Under the second objective, an innovative way to introduce vapours from solid samples was developed. Small amounts of solid crystal sample were heated to produce vapours that were then photoionized. Mass spectra were collected on a number of polycyclic aromatic compounds and metal containing organic compounds. Collision induced dissociation was used to characterize specific analytes of interest. The ability to use a variety of discharge gases for photoionization lowers the cost of construction and improves the ruggedness of photoionization ionization sources. The ability to quickly characterize solid samples has a range of applications including rapid confirmation of synthetic chemistry reactions, quality assurance in pharmaceutical production, detection of drugs of abuse and detection of chemical warfare agents.