Axial mole-fraction profiles were measured in a low-pressure reactive flow of propylene/chlorine and a low-pressure, fuel-rich ethylene flame doped with allene. The purpose was to generate data and test models for improving allyl chloride production and pollutant-related C3 flame chemistry. Molecular-beam mass spectrometry was the principal analytical technique. The propylene/chlorine system had feed conditions of 71.2% propylene and 28.8% chlorine, 76.00 ± 0.01 Torr, and 17.5 cm/s burner-surface gas velocity (298 K). Because propylene and chlorine could pre-react, a novel multidiffusion burner was developed. Mole fraction profiles were mapped for seven stable species. Temperature measurements were made using a K-type thermocouple, and the constant flow cross-section was determined visually. By modeling as a plug-flow reactor with literature rate constants and data and rate constants determined here, a self-consistent reaction mechanism was constructed and used to predict concentration profiles for unmeasured species. Predicted profiles were consistent with measured data. Thus, by also accounting for pressure effects, the new model provides a sound basis for modeling the industrial process. The allene-doped ethylene flame had a fuel equivalence ratio of 1.9 and feed gas composition of 0.5% allene, 18.9% C2H4, 30.9% O 2, and 49.7% Ar. It was operated at 20.00 ± 0.01 Torr with a burner surface gas velocity at 298 K of 62.5 cm/s. Mole fraction profiles were measured for 41 stable and radical species. Data from this allene-doped ethylene flame were compared to the data of Bhargava's (1997) nearly identical fuel-rich undoped ethylene flame. Addition of allene enhanced the production of phenyl and benzene, supporting the arguments that C3 species play a very important role in the formation of phenyl and benzene. Using the data and reaction path analysis, Bhargava's (1997) reaction set was improved. New rate constants were determined, incorrect reactions were removed, and new chemistry was added, improving many of the model predictions. Modeling suggested that the major reaction responsible for increased production of phenyl and benzene was 2C3H3 = phenyl +H. Identification and analysis of an important error in Bhargava's reaction set suggest that a reactive boundary condition at the burner surface may be necessary for improved modeling of this flame.

The solubilization of ferric iron by in vitro digests of chicken muscle proteins was studied. Non-muscle proteins (ovalbumin and casein) were similarly evaluated. The dilute salt insoluble proteins (DSIP) solubilized twice as much iron as the dilute salt soluble proteins. Most of the iron solubilized was ferrous. Only 1% of the total iron solubilized was dialyzable. Maximum iron solubilization was obtained after digestion with pepsin (3 hours) and pancreatin (0.5 hour). Ovalbumin and casein solubilized significantly (p $<$ 0.05) more iron than the DSIP. These proteins may not however enhance iron uptake in vivo. Ultrafiltration of iron-protein digests indicated that most of the iron was bound to proteins or peptides whose molecular weight (MW) was greater than 10000. However, when large (MW $>$ 10000) and small (MW $<$ 10000) peptides were separated by ultrafiltration, their total iron solubilizing capacity was similar. Ultrafiltration could be used to isolate the iron binding peptides of the DSIP fraction. Iron solubilization by DSIP was accompanied by loss of some histidyl and sulfhydryl residues. Chemical modification of each of these residues led to a decrease of about 30% in iron solubilization. Similar effects were observed with free histidine and cysteine but not with glutathione. Interaction of iron with these residues could not account for all the iron solubilized by the DSIP. It was therefore likely that residues or interactions other than these were involved in iron solubilization by the DSIP peptides. It was concluded that the DSIP digest solubilizes iron and enhances iron bioavailability by both complexation and reduction of dietary ferric iron to the more soluble ferrous form partly through its histidyl and sulfhydryl residues.

A method was developed for the quantification of alkylmercury species in complex matrix, biological marine materials. The extraction procedure consists of sample acidification followed by extraction into toluene. Copper powder is added to the extraction vessel to eliminate sulfur interferences. High molecular weight pigments and lipid materials are removed from the sample extracts by preparative gel permeation chromatography prior to gas chromatographic analysis. Separation of the extracted alkylmercury bromides is achieved with a poly(14%-cyanopropylphenyl-86%-dimethylsiloxane) stationary phase capillary column. The organomercury species are detected with a commercial microwave-induced plasma atomic emission detector using atomic emission detector (GC-AED) using the mercury 253.652 nm emission line. Chromatographic and detection parameters were optimized for the quantification of alkylmercury halides. The method was validated with four certified biological tissue reference materials. The methylmercury contents of 19 reference materials of various matrix compositions were determined, including 9 marine standard reference materials from the National Institute of Standards and Technology. Multiple subsamples of each material were analyzed to demonstrate method reproducibility and evaluate material homogeneity. Relative standard deviations below 10% were found for most materials. Trends in methylmercury content and percentage of methylmercury with respect to total mercury were observed for species at differing levels in the marine food web. Agreement among results obtained using the GC-AED method and those obtained using cold vapor atomic absorbtion spectrometry and gas chromatography with atomic fluorescence detection was observed. Beluga whale livers from the Alaskan Marine Mammal Tissue Archival Project were analyzed for methylmercury content. Methylmercury levels increased with whale length, but not with approximate age. Trends were observed in methylmercury content and percentage of methylmercury with respect to total mercury for different whale populations. No relationship between sex and methylmercury content was observed.

Speciation has become an important area of research in the fields of food and environmental analysis because the nutritional value and toxicity of an element depend largely on its chemical form. Elemental speciation requires an efficient separation procedure followed by elementally selective detection. Atomic plasma spectral emission spectroscopy provides powerful element-specific detection for gas chromatography (GC-AED), and today it is utilized in the only commercial available instrument which can be used for both metal and nonmetal speciation. GC-AED has the important advantage of high sensitivity, high elemental selectivity and the possibility of simultaneous multi-element analysis. The atomic emission detection response can flag compounds in the GC effluent which contain specific elements even though these compounds may be present in very small amounts or may co-elute with other components. This dissertation research has been focused on the application of different sample pre-treatment methods coupled with GC-AED for the speciation of organo-selenium in garlic, onion and broccoli. Interest in selenium has heightened in recent years concomitant with the recognition of the element's essential nutritional role, and upon reports of selenium toxicity in humans. Chemical and biochemical pathways in the natural selenium cycle are still not clear because it is very difficult to identify the form of organoselenium compounds at naturally occurring levels. Speciation of organo-selenium compounds at natural levels requires very sensitive and selective detection following an efficient separation and isolation process. Allium species, in particular garlic, have been investigated for a long time. The beneficial properties of garlic feature in the folklore of many cultures around the world. Recently, health benefits of garlic and other related plants, such as onion and broccoli, have been thought to derive from various sulfur- and perhaps selenium-containing compounds in these plants. Identification of the selenium-containing compounds has remained elusive because nature plants contain selenium at levels of less than one ppm, which are orders of magnitude lower than the levels of sulfur present. A large number of papers have been published regarding sulfur chemistry of Allium, but very little information is available on their selenium chemistry. GC-AED was used to achieve the first successful identification and determination of organoselenium compounds at natural levels in plants, these including garlic, onion, broccoli, Chinese chive and radish. Headspace-GC-AED was used to determine trace levels of volatile organoselenium compounds. This has given information on the likely enzymatic degradation of selenium compounds in natural plants. Tenax trap/cryogenic-GC-AED has been used to measure organoselenium compounds in human breath after ingestion of garlic. This has helped the understanding of selenium degradation pass ways in human beings. Another investigation has focussed upon the primarily chemical format of selenium in natural plants; derivatization-GC-AED was used for the determination of free seleno-amino acids. This dissertation also discussed the application of headspace-GC-AED for the determination of 'organo-mercury' in water. Sub-parts per trillion of alkylmercury compounds have been detected in environmental water samples. GC-AED and a membrane introduction mass spectrometer (MIMS) have been used for the study of mechanisms of enzymatic degradation in garlic, major sulfur volatiles released from garlic having been monitored. HPLC-ICP-MS has been investigated for the determination of non-volatile organo-selenium compounds. Investigation on improving the performance of GC-AED were also a part of this research.

Arundodonax (Giant reed Plant) contains cellulose, hemicellulose and lignin and considered as a biomass resources for biofuels. Cellulose is a polymer of several d-glucose linked units coupled with beta-1, 4 glycosidic bonds. The lignin must be broken down to obtain cellulose.Brown and white rot fungusbreak down lignin through a fenton mechanism using hydroxyl radicals. Current work explores degradation of cellulose byisolating microbial communities followed by inoculating 1% carboxymethyl cellulose (CMC) or arundodonax in nutrient media. The microbes demonstrate long-term viability using CMS or arundodonax the sole carbon source.Pretreatment with microbes result in enhanced enzymatic hydrolysis at 50 °C using commercial cellulase over time. The simple dinitrosalicylic acid assay method quantifies glucose, the main product of enzymatic hydrolysis.

The purpose of devising and validating models for intramolecular motions for FMOC amino acids is to quantify side chain motion in proteins which plays an important role in understanding biological structure function relations of proteins. In this thesis, spin lattice relaxation times (Ti) of FMOC amino acids were m easured under both static and magic angle spinning (MAS) condition at variable tem peratures. Lower activation energies of the relaxation times than the normal amino acids observed indicate a less sterically crowded environment for the rotation methyl group. A three-site jump model for the methyl group w as developed to fit the Tiz and Tiq anisotropy under static condition. Under MAS, Multiple deuterated sites can be resolved and studied independently. Finally, a tem perature model for the spinning rotor w as developed to account for the tem perature gradient across the rotor. A com parison of using the single most probable tem perature and the tem perature distribution in the simulation of relaxation times concludes the difference between th ese two approaches is minimal.

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