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Physical Sciences and Mathematics Commons

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Chemistry

Louisiana State University

Mass Spectrometry

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Full-Text Articles in Physical Sciences and Mathematics

Tip-Enhanced Laser Ablation Sample Transfer For Mass Spectrometry, Chinthaka Aravinda Seneviratne Jan 2016

Tip-Enhanced Laser Ablation Sample Transfer For Mass Spectrometry, Chinthaka Aravinda Seneviratne

LSU Doctoral Dissertations

In this research, atomic force microscope tip-enhanced laser ablation mass spectrometry (AFM TELA-MS), an ambient sub-micrometer scale sampling method for offline MS was developed. AFM TELA was used to transfer molecules from thin films to a suspended silver wire for off-line mass spectrometry using laser desorption ionization (LDI) and matrix-assisted laser desorption ionization (MALDI). An AFM with a 30 nm radius gold-coated silicon tip was used to image the sample and to hold the tip 15 nm from the surface for material removal using a pulsed Nd:YAG laser, which provides output at wavelengths of 532 nm in the visible, 1064 …


Matrix-Assisted Laser Desorption Ionization Mass Spectrometry For Identificaiton Of Shrimp, Venkatesulu Salla Jan 2013

Matrix-Assisted Laser Desorption Ionization Mass Spectrometry For Identificaiton Of Shrimp, Venkatesulu Salla

LSU Master's Theses

Matrix-assisted laser desorption ionization (MALDI) time of flight mass spectrometry was used to identify shrimp at the species level using commercial mass spectral fingerprint matching software (Bruker Biotyper). In the first step, a mass spectrum reference database was constructed from the analysis of six shrimp species that are commercially important in the United States: L. setiferus, F. azticus, S. brevirostris, P. robustus, P. dispar and P. platyceros. In the second step, the reference database was tested using 74 unknown shrimp samples from these six species. Correct identification was achieved for 72 of the 74 samples (97 percent): 72 samples were …


Molecular Products From The Thermal Degradation Of Selected Tobacco Components: Lignin, Tyrosine, Glutamic Acid, And Modeling Of Lignin Pyrolysis Using Chemkin Combustion Suite, Joshua Kiprotich Kibet Jan 2013

Molecular Products From The Thermal Degradation Of Selected Tobacco Components: Lignin, Tyrosine, Glutamic Acid, And Modeling Of Lignin Pyrolysis Using Chemkin Combustion Suite, Joshua Kiprotich Kibet

LSU Doctoral Dissertations

This study explores the thermal decomposition behavior of selected tobacco components: lignin, tyrosine, and glutamic acid using the system for thermal diagnostic studies (STDS) in an in-line gas chromatography-mass spectrometer analytical technique. The pyrolysis conditions employed in this study were a flowing atmosphere of nitrogen and 4% O2 in nitrogen at a residence time of 0.2 seconds for a total pyrolysis time of 3 minutes. The results identified common relationships between the two modes of reaction atmospheres, as well as some differences. While some products were favored by an inert regime, some were favored under an oxidative regime. Oxidative pyrolysis …