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No existent analytical method allowed the determination of the vicinal diketones (VDK), 2,3-butanedione (diacetyl) and 2,3-pentanedione, by liquid chromatography/mass spectrometry (LC/MS). An LC/MS method was developed for the simultaneous determination of diacetyl and 2,3-pentanedione in beer. A method allowing the determination of the amino acids (AA) related to the formation of VDK during fermentation was also developed. VDK were derivatized with o-phenylenediamine (OPDA) to form quinoxaline compounds. The reaction of VDK with OPDA was studied to optimize reaction time. Conversion of the diacetyl precursor, alpha-acetolactate, was tested using multiple oxidative decarboxylation techniques. Attempts were also made to determine simultaneously the AA, leucine, isoleucine and valine with the VDK. Simultaneous determination was unsuitable for the AA levels found in beer fermentation and separate methods for the determination of AA were developed. Total VDK were measured over a concentration range of 10 mug/L to 10 mg/L with less than 10% variation. These analytical methods were tested using a laboratory scale experiment to assess the impact of fermentation temperature on total VDK production and AA absorption. Samples collected in a local brewery were analyzed for total VDK using the developed method.

The ability to effectively analyze particulate matter (PM2.5) in air is becoming increasingly pertinent. Allen Goldstein of the University of California in Berkeley is studying the semi-volatile fraction of organic compounds in PM2.5 through the use of the thermal desorption aerosol gas chromatograph (TAG) system. However, as conventional GC does not provide adequate separation power, the development of comprehensive two-dimensional gas chromatography (GC × GC) was required. GC × GC works more effectively by utilizing a modulator that periodically traps and focuses analytes from a primary column onto a secondary column. This allows for the primary and secondary columns to separate the analytes based on two different properties. This report focuses on the continuing study and enhancement of a modulator designed by Ognjen Panić during his Masters project. Improving and testing the robustness of this dual stage modulator was originally the focus of this project. However, this study led to the development of a single stage modulator. In addition to that, the effect of modulator characteristics such as length of the restriction, total length of the modulator and wall thickness on the modulator performance were studied. A robustness test of the single stage modulator was also completed. Experiments conducted tested the characteristics of the new modulator to ensure it performed effectively and would satisfy the requirements of the TAG system. A study comparing the sensitivity of conventional gas chromatography and GC × GC was also preformed. The sensitivity of GC × GC was on average an order of magnitude better than that of 1D GC.

In this study, we describe the use of different silica materials to separate vanadium compounds from Asphaltenes. We used high performance flash chromatography separation method to separate asphaltenes at different solvent strengths on sea sand. The separation conditions were optimized for flow rate and the strength of the solvent. The selectivity of separation was determined based on asphaltene and metal recovery. With separation on sea sand as the solvent strength increased, the recovery percentage of the asphaltenes also increased. Similarly, stronger solvent blends give poor selectivity based on peak shifts in fluorescence spectra. The separation conditions were then used to compare the performance of a series of silica materials treated with alkaline earth metals. These samples were treated with the same molar concentration of reactant at the same temperature. Treatment of silica materials resulted in an increase in metals recovery and asphaltene recovery by providing less active sites for adsorption. / Chemical Engineering

Typescript. / Thesis (Ph. D.)--University of Hawaii, 1968. / Bibliography: leaves [80]-87. / xi, 87 l illus., tables

In Australia, the 0.22 calibre ammunition is the most encountered ammunition type found at a crime scene [1]. Previous analysis of gun shot residue (GSR) and unfired propellant has involved studying the inorganic constituents by Scanning Electron Microscopy or similar technique. However, due to the heavy metal build up that comes with some ammunition types, manufacturing companies are now making propellant that is safer to use. Therefore, it has become appropriate to study and analyse unfired propellant by other means. One such technique is unfired propellant analysis by gas chromatography – mass spectrometry (GC-MS). This technique focuses on the organic constituent make up of the propellant paying particular attention to diphenylamine, ethyl centralite and dibutyl phthalate. It was proposed that different batches of ammunition could be discriminated or matched to each other by using this technique. However, since the main constituents of unfired propellant are highly reactive, it was not possible to accomplish batch determination of ammunition. However, by improving extraction techniques and by removing oxygen (a catalyst for the degradation of diphenylamine) a superior method was established to help in the analysis of unfired propellant. Furthermore, it was shown that whilst differentiating batches of the same ammunition was not possible, the improved methods have helped identify different types of the same brand of ammunition. With the aid of future studies to fully explore this avenue, the analysis of unfired propellant could one day become an integral part of forensic science.

Thesis (Ph. D.)--Brigham Young University. Dept. of Chemistry and Biochemistry, 2007. / Includes bibliographical references.

Thesis (M.S.)--West Virginia University, 2007. / Title from document title page. Document formatted into pages; contains viii, 87 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 72-73).

Diss. (sammanfattning) Uppsala : Uppsala universitet, 2007. / Härtill 4 uppsatser.

Thesis (Ph.D.) -- McMaster University, 1998. / Includes bibliographical references (leaves 139-148). Also available via World Wide Web.