Distinguishing animal fats from plant oils in archaeological residues is not straightforward. Characteristic plant sterols, such as ß-sitosterol, are often missing in archaeological samples and specific biomarkers do not exist for most plant fats. Identification is usually based on a range of characteristics such as fatty acid ratios, all of which indicate that a plant oil may be present, none of which uniquely distinguish plant oils from other fats. Degradation and dissolution during burial alter fatty acid ratios and remove short-chain fatty acids, resulting in degraded plant oils with similar fatty acid profiles to other degraded fats. Compound-specific stable isotope analysis of ¿(13)C(18:0) and ¿(13)C(16:0), carried out by gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS), has provided a means of distinguishing fish oils, dairy fats, ruminant and non-ruminant adipose fats, but plant oils are rarely included in these analyses. For modern plant oils where C(18:1) is abundant, ¿(13)C(18:1) and ¿(13)C(16:0) are usually measured. These results cannot be compared with archaeological data or data from other modern reference fats where ¿(13)C(18:0) and ¿(13)C(16:0) are measured, as C(18:0) and C(18:1) are formed by different processes resulting in different isotopic values. Eight samples of six modern plant oils were saponified, releasing sufficient C(18:0) to measure the isotopic values, which were plotted against ¿(13)C(16:0). The isotopic values for these oils, with one exception, formed a tight cluster between ruminant and non-ruminant animal fats. This result complicates the interpretation of mixed fatty residues in geographical areas where both animal fats and plant oils were in use.

The United States Environmental Agency permits the use of 39 organophosphate pesticides. Many of these pesticides are acutely toxic and have lasting effect on human health. Organophosphates quickly metabolize in the body, therefore currently human exposure is studied by measuring the metabolic products in urine. In this work a suite of analytical methods was developed to determine the presence of un-metabolized organophosphate pesticides in human serum. First mass spectroscopic detection methods were evaluated. Gas chromatograph coupled tandem mass spectrometer was used to compare the detection limits using chemical and electron impact ionization. Positive chemical ionization was selected, because it provided better detection limits for this set of analytes. Liquid chromatograph coupled tandem mass spectrometry was also evaluated and was found advantageous over the gas chromatographic method for approximately 50% of the compounds. Positive atmospheric pressure chemical ionization was chosen for this group of compounds. Once the analytes were separated by detection methods, analytical separation methods were compared: column and eluent was selected for liquid chromatography, column alone was selected for gas chromatography. Last step of the method development was to produce a suitable sample cleanup process. Solid phase extraction was not suitable because the very wide range of solubility characteristics and hydrolytic stability of the analytes. Lyophilization, liquid-liquid extraction methods were tested and compared. A multi step cleanup method was produced, which starts with liquid-liquid extraction using high pressure ethyl acetate in accelerated solvent extractor, solvent exchange and a lipid removal step. The concentrated extract then injected in a HPLC-MS-MS system then the same extract either directly injected in GC-MS-MS or further purified using headspace solid phase micro extraction before the GC-NS-MS step. The method was used with good results for analyzing samples collected from farm workers using OP pesticides.

Isoelectric focusing (IEF) is a powerful approach in separations of zwitterionic substances such as proteins, peptides and amino acids. It is important in proteomic research. Generally, in IEF, carrier ampholytes (CAs) are necessary to establish a stable pH gradient. However, CAs also bring attendant problems such as a decrease in detection sensitivity and suppression of ionization of analytes in mass spectrometry (MS) detection. It is desirable to build a pH gradient without using CAs. A simple slab based design was developed to establish a pH gradient using the electrolysis of water and the strength of free flow electrophoresis (FFE). The simple and robust CA free FFE-IEF design was applied in protein fractionation. In capillary format, capillary isoelectric focusing (CIEF), coupled to MS is a promising hyphenated technique for biomolecular analysis based on the combination of the high separation power of CE and the high specificity of MS. Coupling of the instruments is usually achieved with a coaxial sheath liquid interface, which decreases the detection sensitivity because of the dilution of sample by the sheath liquid. In this project, nano-electrospray, a sheathless interface, was used for coupling. Additionally, another major challenge is the presence of CAs which suppresses the ionization of analytes and contaminates the MS. In order to complete this project, a microcross union was chosen to couple CIEF with MS. A makeup solution was introduced to dilute the concentration of CAs after IEF to assist the ionization for MS detection. The makeup solution could replace the sheath liquid and could be maintained at a low flow rate so that nanoelectrospray could be performed. Monoliths can be described as integrated continuous porous separation media for micro scale separation columns. CAs were immobilized at different positions in the column according to their pIs, generating a monolithic immobilized pH gradient (M-IPG). In this project, carrier ampholytes was immobilized in poly (GMA-co-EDMA) based monolithic capillary and poly (GMA-co-acrylamide) based monolithic capillary to form a pH gradient. Two proteins were separated by IEF, which was implemented in poly (GMA-co-acrylamide) based monolithic capillary without CAs. The interface to MS was performed following the use of a microcross union as described previously. No typical noise of CAs was observed in the MS spectrum.

Isoelectric focusing (IEF) is a powerful approach in separations of zwitterionic substances such as proteins, peptides and amino acids. It is important in proteomic research. Generally, in IEF, carrier ampholytes (CAs) are necessary to establish a stable pH gradient. However, CAs also bring attendant problems such as a decrease in detection sensitivity and suppression of ionization of analytes in mass spectrometry (MS) detection. It is desirable to build a pH gradient without using CAs. A simple slab based design was developed to establish a pH gradient using the electrolysis of water and the strength of free flow electrophoresis (FFE). The simple and robust CA free FFE-IEF design was applied in protein fractionation. In capillary format, capillary isoelectric focusing (CIEF), coupled to MS is a promising hyphenated technique for biomolecular analysis based on the combination of the high separation power of CE and the high specificity of MS. Coupling of the instruments is usually achieved with a coaxial sheath liquid interface, which decreases the detection sensitivity because of the dilution of sample by the sheath liquid. In this project, nano-electrospray, a sheathless interface, was used for coupling. Additionally, another major challenge is the presence of CAs which suppresses the ionization of analytes and contaminates the MS. In order to complete this project, a microcross union was chosen to couple CIEF with MS. A makeup solution was introduced to dilute the concentration of CAs after IEF to assist the ionization for MS detection. The makeup solution could replace the sheath liquid and could be maintained at a low flow rate so that nanoelectrospray could be performed. Monoliths can be described as integrated continuous porous separation media for micro scale separation columns. CAs were immobilized at different positions in the column according to their pIs, generating a monolithic immobilized pH gradient (M-IPG). In this project, carrier ampholytes was immobilized in poly (GMA-co-EDMA) based monolithic capillary and poly (GMA-co-acrylamide) based monolithic capillary to form a pH gradient. Two proteins were separated by IEF, which was implemented in poly (GMA-co-acrylamide) based monolithic capillary without CAs. The interface to MS was performed following the use of a microcross union as described previously. No typical noise of CAs was observed in the MS spectrum.

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A single-ultrafine-particle mass spectrometer was constructed and deployed for size-resolved ultrafine aerosol composition measurements during the winter of 2002-2003 in College Station, Texas. Three separate experiments were held between December and March with six week intervals. Almost 128,000 mass spectra, corresponding to particles with aerodynamic diameters between 35 and 300 nm, were collected and classified. Fifteen statistically significant classes were identified and are discussed in this paper. Nitrate, potassium, carbon, and silicon/silicon oxide were the most frequently observed ions. Nitrate was present in most of the particles, probably due to the agricultural activity in the vicinity of the sampling site. The nitrate detection frequency was found to be sensitive to the ambient temperature and relative humidity. Another particle class, identified as an amine, exhibited strong relative humidity dependence, appearing only during periods of low relative humidity. There is evidence that some of the detected particles originated from the large urban centers, and were coated with nitrate, sulfate, and organics during transport.

Thesis (Ph. D.)--University of Texas at Austin, 2000. / Vita. Includes bibliographical references (leaves 112-119). Available also in a digital version from Dissertation Abstracts.

Thesis (M.Sc.)--York University, 2007. Graduate Programme in Chemistry. / Typescript. Includes bibliographical references (leaves 71-75). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:MR38780

Thesis (Ph. D.)--University of Florida, 2006. / Title from title page of source document. Document formatted into pages; contains 227 pages. Includes vita. Includes bibliographical references.