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In this project, the optimization of obtaining adsorption isotherms for the ion pair reagent, tributylamine was tested. The goal was to have a better understanding of the chromatographic process when separating biomolecules, such as oligonucleotides. To do this one ion pair reagent was tested in different buffers with different compositions of acetonitrile. These solutions adsorbed into a C18 column at different temperatures and stripped into fractions of 35 mL. To analyze the results Liquid-liquid extraction was performed on the fractions and the organic phase was then injected into a gas chromatography. The results showed that at a temperature of 24°C the ion pair reagent adsorbed more to the column than at 37°C and 50°C. For the different compositions of acetonitrile buffers which were tested the one that stood out was the 50% acetonitrile buffert. At all temperature it showed to always be able to adsorb more to the column than the other buffers. To calculate the concentrations of the analytes, standard curves for both tributylamine and dibutylamine were made. For dibutylamine, four unknown samples were provided to test out if the methods could be used to determine the concentrations of dibutylamine in the samples. The methods for acquiring adsorption isotherms and analyzing samples with the gas chromatography showed good results and could be used for more studies. However, to validate the results of the 50% acetonitrile buffer, more work in the future is required.

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Biogas, a gaseous mixture produced during decomposition of organic matter, is a renewable, easily generated and common byproduct of anaerobic digestion at wastewater treatment plants (WWTP), landfills and agricultural operations. There is growing interest in researching and utilizing the energy potential associated with its combustion. Siloxanes, a family of volatile organic silicon compounds, pose large impediments to biogas usage due to the formation and precipitation of silicon dioxide within combustion devices. Removal of siloxanes prior to combustion is therefore a growing endeavor. Research was performed to synthesize a representative gas stream produced from anaerobic digesters within WWTP. Methane, carbon dioxide and hydrogen sulfide were combined with humidity and gaseous siloxane in levels characteristically seen exiting anaerobic digesters. A methanol impinger train was utilized to sample the biogas composite. Gas chromatography-mass spectrometry (GC-MS) was used to determine gas-phase siloxane concentrations in the gas stream effluent for the purposes of confirming the generation of a consistent and reproducible biogas stream. / Master of Science

Lipids are important for the structural and physiological functions of neuronal cell membranes. Alterations in their lipid composition may result in membrane dysfunction and subsequent neuronal deficits that characterise various disorders. This study focused on profiling lipids of aged and LPS-treated rat brain and liver tissue with a view to explore the effect of atorvastatin in neuroinflammation, and examining lipid changes in different areas of rat brain of the Flinders Sensitive Line (FSL) rats, a genetic model of depression. Lipids and other analytes extracted from tissue samples were analysed with proton nuclear magnetic resonance spectroscopy (1H-NMR), gas chromatography (GC) and liquid chromatography-tandem mass spectroscopy (LC/ESI-MS/MS). Changes in the lipid profiles suggested that brain and liver responded differently to ageing and LPS-induced neuroinflammation. In the aged animals, n-3 PUFA were reduced in the brain but were increased in the liver. However, following treatment with LPS, these effects were not observed. Nevertheless, in both models, brain concentration of monounsaturated fatty acids was increased while the liver was able to maintain its monounsaturated fatty acid concentration. Atorvastatin reversed the reduction in n-3 PUFA in the aged brain without reducing brain and liver concentration of cholesterol. These findings further highlight alterations in lipid metabolism in agerelated neuroinflammation and show that the anti-inflammatory actions of atorvastatin may include a modulation of fatty acid metabolism. When studying the FSL model, there were differences in the lipid profile of different brain areas of FSL rats compared to Sprague-Dawley controls. In all brain areas, arachidonic acid was increased in the FSL rats. Docosahexaenoic acid and ether lipids were reduced, while cholesterol and sphingolipids were increased in the hypothalamus of the FSL rats. Furthermore, total diacylglycerophospholipids were reduced in the prefrontal cortex and hypothalamus of the FSL rats. These results show differences in the lipid metabolism of the FSL rat brain and may be suggestive of changes occurring in the brain tissue in depression.

<p> This thesis focused on the development of comprehensive, rapid and simple methodologies for the analysis of fatty acids by gas chromatography mass spectrometry (GC/MS) and intact lipids by electrospray ionization tandem mass spectrometry (ESIIMS/MS). The methodologies were applied as a tool for functional genomics in the soil bacterium Sinorhizobium meliloti. The effects of inorganic phosphate (Pi)-starvation and acidity on lipid composition were studied. </p> <p> A micro-scale, one-vial method for the analysis of fatty acids as their fatty acid methyl esters by GC/MS was developed. The method required small sample sizes, involved minimum handling and avoided tedious extraction steps, which increased sample throughput. A series of quality controls were included to measure losses due to handling, derivatization efficiencies and the extent of side reactions. The method was suitable for the analysis of sensitive bacterial fatty acids such as cyclopropane fatty acids. </p> <p> A shotgun lipidomics approach was developed for the analysis of intact lipids by ESIIMS/MS. Fatty acid distributions were obtained for eight lipid classes and up to 58 individual lipids were identified in crude lipid extracts without sample cleanup or chromatography. For the first time, fatty acid distributions were provided for non-phosphorus containing lipids using shotgun lipidomics. Fatty acid distributions within lipid classes suggested that phospholipids and 1,2-diacylglyceryl-3-O-4'-(N,N,N-trimethyl)-homoserine lipids (TMHSs) were both synthesized from phosphatidic acid while sulfoquinovosyldiacylglycerol (SLs) had a different biosynthetic origin. </p> <p> The methodologies were applied to study knockout mutants of five genes thought to participate in lipid metabolism in S. meliloti. It was demonstrated that: (1) cfa2 gene coded for the main cyclopropane fatty acyl synthase; (2) the plsC gene coded for a fatty acy 1 transferase specific for C 16 fatty acids in the sn-2 position of phospholipids; (3) a metabolic phenotype was revealed for knockout mutants of dme and tme genes (DME and TME, malic enzymes) when succinate was the carbon source. </p> / Thesis / Doctor of Philosophy (PhD)

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The industrial revolution caused the release of carbon dioxide (CO2) into the atmosphere leading to a climate crisis. The impact of more CO2 in the atmosphere has been experienced by everybody. The summers are longer and hotter, while the winters are colder and shorter. The ocean water has become more acidic threatening the ocean life. There is an immediate need to reduce CO2 and switch to alternate energy for human survival. Electrochemical reduction of CO2 (ERC) is a promising technology capable of converting excess CO2 into valueded products. The process of recycling CO2 can address the problem of excess CO2 and is a sustainable solution until our dependence on fossil fuels is reduced. However, currently there are very few catalysts that can convert CO2 into valuable products with a low overpotential. The current research evaluates new catalysts for their ERC potential. [Ni(cyclam)]2+ is a well-known catalyst used to reduce CO2 homogeneously. Therefore, it was used as a standard to optimize the CO2 evaluation protocol. Two new catalysts developed in Dr. Hollis's laboratory, a Pt- pincer and a Fepincer molecule were assessed using this method. Cyclic voltammetry and bulkelectrolysis (BE) experiments were performed under Ar and CO2 environments. The gaseous products from BE were primarily CO and H2 and their quantitative measurement was performed using gas chromatography. Formate determination was performed using UV-Vis spectroscopy. Faradaic yields were calculated for CO, H2, and formate. The overpotentials were calculated for all the processes, and a comparison was made to determine the most efficient process. The turnover numbers (TON) and the turnover frequencies (TOF) of all the catalysts were calculated. Based on all the criteria, the Fepincer complex was determined to be the most promising catalyst for further optimization. Additionally, a Faradaic efficiency calculation spreadsheet was created to improve calculation efficiency. The protocol described here has been successfully applied to assess new catalysts and can prove to be an invaluable tool when numerous catalysts require evaluation.

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