Physical Sciences and Mathematics Commons^™

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 …

From Whole-Cell To Compartment- And Class-Specific Analysis Of Rna Post-Transcriptional Modifications, Ryan Quinn

Legacy Theses & Dissertations (2009 - 2024)

The genomic structure of the human immunodeficiency virus type 1 (HIV-1) has proven difficult to examine by traditional high-resolution techniques. Structural probing and in silico modeling have been turned to the task instead. Computer models are only as robust as the data used to create them. A number of techniques were explored in this investigation to expand the utility of in silico modeling as it relates to HIV-1: the study of nucleoside modifications, and the probing of in vivo conformations of the 5'-untranslated region (5'-UTR) by cross-linking and affinity capture.

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 …

Sample Preparation Techniques For The Improvement Of Analytical Measurements: Capillary-Channeled Polymer Fibers Employed In Protein Solid Phase Extraction Applications And Characterization Of Active Components In Botanical Dietary Supplements, Carolyn Burdette

All Dissertations

The task of sample preparation encompasses many challenges and demands for analytical techniques. Appropriate preparative steps can be the determining factor between successful measurements and failures. Too little preparation can lead to the inability to detect analytes due to low concentrations, insufficient extraction of analytes, and/or strong matrix effects; exhaustive preparation steps increases analysis times, the potential for analyte losses, and the difficulty to obtain consistent reproducible results. Discussed here are several examples of analytical techniques where sample preparation is critical and can be used to improve existing techniques. Capillary-channeled polymer (C-CP) fibers used for solid phase extraction (SPE) protein …

A Discovery-Oriented Approach To Solid-Phase Peptide Synthesis, Brian B. Brennan, Matthew R. Bockman, Christopher J. Miedema

Brian B. Brennan

Rat Brain Pro-Oxidant Effects Of Peripherally Administered 5 Nm Ceria 30 Days After Exposure, Sarita S. Hardas, Rukhsana Sultana, Govind Warrier, Mo Dan, Rebecca L. Florence, Peng Wu, Eric A. Grulke, Michael T. Tseng, Jason M. Unrine, Uschi M. Graham, Robert A. Yokel, D. Allan Butterfield

Chemistry Faculty Publications

The objective of this study was to determine the residual pro-or anti-oxidant effects in rat brain 30 days after systemic administration of a 5 nm citrate-stabilized ceria dispersion. A ∼4% aqueous ceria dispersion was iv-infused (0 or 85 mg/kg) into rats which were terminated 30 days later. Ceria concentration, localization, and chemical speciation in the brain was assessed by inductively coupled plasma mass spectrometry (ICP-MS), light and electron microscopy (EM), and electron energy loss spectroscopy (EELS), respectively. Pro- or anti-oxidant effects were evaluated by measuring levels of protein carbonyls (PC), 3-nitrotyrosine (3NT), and protein-bound-4-hydroxy-2-trans-nonenal (HNE) in the hippocampus, cortex, and …

A Discovery-Oriented Approach To Solid-Phase Peptide Synthesis, Brian Brennan, Matthew Bockman, Christopher Miedema

Scholarship

In this discovery-oriented laboratory experiment, students use solid-phase synthesis techniques to construct a dipeptide containing an unknown amino acid. Following synthesis and cleavage from the polymeric support, electrospray ionization-mass spectrometry is employed to identify the unknown amino acid that was used in the peptide coupling. This experiment, performed in two, 3-h laboratory periods, provides an opportunity for students to learn the technique of solid-phase peptide synthesis and to critically evaluate data that they generate in the laboratory. The experiment is suitable for second-semester organic chemistry students as they learn methods for the formation of amide bonds or upper-level biochemistry students …

Characterization Of The Desorption Electrospray Ionization Mechanism Using Microscopic Imaging Of The Sample Surface, Michael Craig Wood

Theses and Dissertations

Desorption electrospray ionization (DESI) is an ambient ionization technique for mass spectrometry. This solvent based desorption ion source has wide applicability in surface analysis with minimal sample preparation. Interest in improving detection limits, broadening applications, and increasing the spatial resolution for chemical imaging has led to studies of the DESI mechanism. An inverted microscope has been used to image interactions between the DESI spray and test analytes on a glass surface. Microscopic images recorded with millisecond time resolution have provided important insights into the processes governing analyte transport and desorption. These insights are the basis of a rivulet-based model for …

Liquid Extraction Based Surface Sampling: Liquid Microjunction Surface Sampling Probes Coupled With Mass Spectrometry, Matthew John Walworth

Doctoral Dissertations

The direct sampling of analytes from surfaces under atmospheric conditions followed by mass spectrometric analysis is an ever expanding area of scientific research. Atmospheric pressure surface sampling and ionization techniques for mass spectrometry (MS) offer the ability to interrogate samples that could not be studied under vacuum conditions required of more traditional MS surface analysis techniques. The geometry and nature of materials or surfaces that can be analyzed has been greatly expanded as a result. This dissertation characterizes and shows applications of liquid microjunction surface sampling probe (LMJ-SSP) electrospray ionization systems. The presented work compares traditional analytical work flows with …

Optimization And Validation Of Direct Analysis In Real Time Mass Spectrometry (Dart-Ms) For Quantitation Of Sugars To Advance Biofuel Production, Daudi Sayialel Saang'onyo

Online Theses and Dissertations

A direct analysis in real time mass spectrometry method was developed and validated for the analysis and quantitation of sugars that would be generated from pretreated and hydrolyzed switchgrass. This research aspect can be divided into two sections:

i) Literature Review: A review is presented on the status of energy security and how biomass and biofuels can be utilized as a source of transportation fuel. To this end, biomass (specifically switchgrass) can be broken down by pretreatment methods and then enzymatically hydrolyzed to simple sugars. These sugars can assist with algae growth that can eventually be converted into biofuels. …

Structural Characterization Of The Pre-Amyloid Oligomers Of Β-2-Microglobulin Using Covalent Labeling And Mass Spectrometry, Vanessa Leah Castillo Mendoza

Open Access Dissertations

The initial steps involved in the assembly of normally soluble proteins into amyloid fibrils remain unclear, yet over 20 human diseases are associated with proteins that aggregate in this manner. Protein surface modification is a potential means of mapping the interaction sites in early oligomers that precede amyloid formation. This dissertation focuses on the use of covalent labeling combined with mass spectrometry to elucidate the structural features of Cu(II)-induced β-2-microglobulin (β2m) amyloid formation. An improved covalent modification and MS-based approach for protein surface mapping has been developed to address the need for a reliable approach that ensures protein structural integrity …

Electrospray Ionization Mass Spectrometry For The Characterization Of Covalent And Noncovalent Polynuclear Platinum Compounds Interacting With Bio-Molecules, John Mangrum

Theses and Dissertations

Polynuclear platinum compounds represent a new class of potential platinum anticancer therapeutics. Derived from the most widely used platinum anticancer drug, cisplatin, these novel compounds are distinct in their interactions with bio-molecules. The effectiveness of platinum anticancer agents is influenced by three pharmacological factors: (i) their resistance to deactivating sulfur nucleophiles, (ii) the ability to gain cellular entry and efficient cellular uptake, and (iii) the ability to form stable and specific complexes with DNA. BBR 3464, the first multinuclear platinum compound to reach phase II clinical trials, has created a new approach to cancer drug design. Large, highly charged platinum …

Explorations In Homeoviscous Adaptation And Mass Spectral Analysis Of Membrane Lipids, Michael Douglas Timmons

University of Kentucky Doctoral Dissertations

The focus of this dissertation is centered on the mass spectral analysis of lipids and changes occurring in keeping with the concept of homeoviscous adaptation [1]. Homeoviscous adaptation is the process of modification of membrane lipids in response to environmental stimuli [1]. Dissertation investigations applied this concept to prokaryotic and eukaryotic organisms, and expanded the perception of environmental factors from exogenous organic solvents to intracellular environment.

The field of lipidomics deals with the analysis of phospholipid and fatty acid components of membranes the changes that occur due to environmental stimuli and their biological significance [2-6]. The high sensitivity of mass …

Developing Novel Electrospray Ionization Mass Spectrometry (Esi Ms) Techniques To Study Higher Order Structure And Interaction Of Biopolymers, Agya K. Frimpong

Open Access Dissertations

Mass spectrometry has enjoyed enormous popularity over the years for studying biological systems. The theme of this dissertation was to develop and use mass spectrometry based tools to solve five biologically oriented problems associated with protein architecture and extend the utility of these tools to study protein polymer conjugation. The first problem involved elucidating the false negatives of how proteins with few basic residues, forms highly charged ions in electrospray ionization mass spectrometry (ESI MS). This study showed that the unfolding of polypeptide chains in solution leads to the emergence of highly charged protein ions in ESI MS mass spectra, …

The Development Of An Optimized System Of Narcotic And Explosive Contraband Mimics For Calibration And Training Of Biological Detectors, Michael S. Macias

FIU Electronic Theses and Dissertations

Current commercially available mimics contain varying amounts of either the actual explosive/drug or the chemical compound of suspected interest by biological detectors. As a result, there is significant interest in determining the dominant chemical odor signatures of the mimics, often referred to as pseudos, particularly when compared to the genuine contraband material. This dissertation discusses results obtained from the analysis of drug and explosive headspace related to the odor profiles as recognized by trained detection canines. Analysis was performed through the use of headspace solid phase microextraction in conjunction with gas chromatography mass spectrometry (HS-SPME-GC-MS). Upon determination of specific odors, …

Methods Development In Qualitative And Quantitative Proteomics, Ting Liu

University of Kentucky Doctoral Dissertations

Proteomics based on liquid chromatography coupled to mass spectrometry has developed rapidly in the last decade and become a powerful tool for protein mixtures analysis. LC-MS based proteomics involves four steps, sample preparation, liquid chromatography, mass spectrometry and bioinformatics. Improvements in each step have extended its applications to new biological research areas. This dissertation mainly focuses on method developments in both qualitative and quantitative proteomics.

The first part of this dissertation focuses on qualitative analysis of T. gondii Parasitophorous Vacuole Membrane (PVM) proteins, which is very important for T. gondii’s survival. The hypothesis of this study is that proteomic …

Characterization Of Microorganisms Of Interest To Homeland Security And Public Health Utilizing Liquid Chromatography/Mass Spectrometry, Robert A. Everley

Theses and Dissertations

Liquid chromatography/quadrupole time of flight mass spectrometry (LC/QTOF MS) utilizing electrospray ionization was employed to monitor protein expression in Escherichia coli and Shigella organisms. Automated charge state deconvolution, spectral subtraction and spectral mirroring were used to reveal subtle differences in the LC/MS data. Reproducible intact protein biomarkers were discovered based on their unique mass, retention time and relative intensity. These markers were implemented to differentiate closely related strain types, (e.g. two distinct isolates of E. coli O157:H7) and to correctly identify unknown pathogens. Notable, was the distinction of multiple serotypes of enterohaemorrhagic E. coli which cannot be distinguished by clinical …

Counter-Flow Ion Mobility Analysis: Design, Instrumentation, And Characterization, Nosa Agbonkonkon

Theses and Dissertations

The quest to achieve high resolution in ion mobility spectrometry (IMS) has continued to challenge scientist and engineers in the field of separation science. The low resolution presently attainable in IMS has continued to negatively impact its utility and acceptance. Until now, efforts to improve the resolution have mainly focused on better instrumentation and detection methods. However, since the resolution of IMS is diffusion limited, it makes sense to address this limitation in order to attain high resolution. This dissertation presents a new IMS technique, which utilizes a high electric field and opposing high gas flow velocity with the aim …

Ammonia Elimination From Protonated Nucleobases And Related Synthetic Substrates, Ming Qian, Shuo Yang, Hong Wu, Papiya S. Majumdar, Nathan D. Leigh, Rainer Glaser

Chemistry Faculty Research & Creative Works

The results are reported of mass-spectrometric studies of the nucleobases adenine 1h (1, R = H), guanine 2h, and cytosine 3h. The protonated nucleobases are generated by electrospray ionization of adenosine 1r (1, R = ribose), guanosine 2r, and deoxycytidine 3d (3, R = deoxyribose) and their fragmentations were studied with tandem mass spectrometry. In contrast to previous EI-MS studies of the nucleobases, NH₃ elimination does present a major path for the fragmentations of the ions [1h + H]⁺, [2h + H]⁺, and …

Data Retrieval In Mass Spectrometry By An Optical Coincidence System, Cynthia Helmintoller O'Donohue

Master's Theses

The object of this work was to develop an information storage and retrieval system for use in mass spectroscopy. The information to be stored was the compound's name, the mass spectrum, and distinctive physical and chemical properties. It was desirable that the system be one that could be used in the mass spectral laboratory. At the time this project was initiated, no system for mass spectroscopy had been developed with the characteristics of simplicity, rapid retrieval, and practicality of use in the laboratory without elaborate and space consuming equipment. Thus, a system was needed to aid the laboratory personnel in …