Abstract not available

The main thrust of this study is to examine the thermal decomposition of several metal chelates and of polypropylene, and to find how the two interact with one another to produce a possible flame retardant effect in the polymer. Several metal acetylacetonates were examined by thermogravimetric analysis (TGA) in order to determine their thermal stability with respect to atactic polypropylene (APP) and isotactic polypropylene (IPP). These chelates were not suitable so the benzoylacetonates and dibenzoylmethonates, (BA) and (DBM), were made of iron and chromium (III). These four chelates were found to be more thermally compatible with APP and IPP. The four chelates were pyrolyzed in both inert and oxidative atmospheres and their pyrolysis products were examined using chromatography and mass spectrometry and the combination of the two (GC-MS). The pyrolysis products were mostly aromatic aldehydes and ketones, from both the inert and oxidative atmosphere pyrolysis. A mechanism for the thermal degradation of these chelates was proposed. Polypropylene was pyrolyzed and the products were examined with capillary GC-MS. In an inert atmosphere the products of APP pyrolysis were hydrocarbons, mostly olefins. In oxidative pyrolysis, the products were primarily aldehydes and ketones. Proposed mechanisms for the thermal decomposition of APP in inert and oxidative atmospheres were examined and explained some of the observed products but not all of them. The pyrolysis of the head to head polypropylene was also examined and a mechanism was proposed which accounted for most of the pyrolysis products which were observed. One of the chelates, chromium benzoylacetonate, was added to the APP samples and lowered the total amount of volatiles produced by as much as 20%.

This dissertation considers the development of new analytical techniques to characterize shale oil, with emphasis on the heteroorganic compounds. A class separation precedure using preparative liquid chromatography on an amino-bonded silica support was developed to allow separation of shale oil into four chemical classes, namely: (1) hydrocarbons (alkanes/alkenes), (2) polynuclear aromatics, (3) acids and neutral polars, and (4) bases. This procedure was applied to the analysis of two different types of shale oil, Tosco II and In-Situ. All four classes of compounds were then characterized by capillary gas chromatography with flame ionization detection and some were also examined with the thermionic nitrogen specific detector. The acids and bases were further characterized by capillary gas chromatography with interfaced mass spectroscopy. Comparison of the two oils showed that although the level of heteroorganic compounds is different, the distribution of compounds within the same class is very similar. An argentation liquid chromatographic procedure was developed for isolation of the thiophenic compounds in shale oil. This is an important class of compounds to study since it encompasses approximately 80% of the organic sulfur content. Existing methods for isolation of thiophenes depend on a chemical reaction step. These methods fail to maintain the integrity of the thiophenes due either to discrimination dependent on the alkyl substituents present or to chemical alteration of some of the compounds. The argentation procedure avoided this discrimination since the retention time on the liquid chromatographic column was almost independent of the number and type of alkyl substituents on the thiophene ring. From direct comparison with the existing chemical methods, the argentation procedure was shown to be superior in recovering the thiophenes without discrimination.

The technique of alkali fusion reaction gas chromatography has been applied to the analysis and characterization of polycyanoalkylsiloxanes, polyalkoxysiloxanes, and poly-m-carboranylsiloxanes. A reaction system was designed to allow the efficient and quantitative conversion of the organo-functional and silicon-functional groups to products sufficiently volatile for gas chromatographic analysis. Milligram or less quantities of material were reacted at elevated temperatures in a flowing inert atmosphere for periods of 15 minutes or less. Upon completion of the reaction, the cryogenically trapped fusion products were flash volatilized onto the gas chromatograph column for separation and quantitation. A mini volume switching valve allowed the simultaneous occurrence of polymer fusion and product chromatography of a previous fusion. The average percent relative standard deviation was 1.2%. The thermal degradation properties of the poly-m-carboranylsiloxanes were studied by pyrolysis gas chromatography encompassing the ancillary techniques of selective element detection and mass spectroscopy. A gas chromatograph was interfaced with an atmospheric pressure microwave induced and sustained plasma emission detector for boron pyrolyzate analysis and an atmospheric pressure d.c. argon plasma emission echelle spectrometer for silicon pyrolyzate analysis. The use of selective element detection simplified the interpretation of the complex pyrograms and facilitated the mass spectral determination of the pyrolyzate structures. The thermal degradation of the poly-m-carboranylsiloxanes cannot proceed through an intramolecular cyclization pathway due to the steric restraints imposed by the presence of the carborane cage in the siloxane backbone. It was postulated that the m-carboranylsiloxanes depolymerize by an intermolecular pathway; the presence of cyclic siloxane pyrolyzates was shown to be consistent with this pathway.

Thermal analysis and analytical pyrolysis have been performed on selected phosphazene and silarylene-siloxane polymers for the following purposes: first, to investigate their low and high temperature behavior, secondly, to evaluate gas chromatography-element selective detection as a tool for analytical pyrolysis and lastly, to identify the pyrolysis products and to propose degradation mechanisms for these polymers. Thermal analytical techniques employed were differential scanning calorimetric (DSC) and thermal gravimetric analyses (TGA) as well as elemental analyses. For the phosphazenes, elemental analyses gave results consistent with those predicted from the repeating structures of the polymers. DSC and TGA data were also consistent with that reported for phosphazenes of similar structure in the literature. For the silarylene-siloxanes elemental analyses, DSC and TGA data were all inconsistent with data reported in the literature. Attempts to elucidate the reason(s) for these discrepancies using infrared, ('1)H NMR, and ('13)C NMR spectroscopies and gel permeation chromatography were inconclusive. Two methods of element selective detection were evaluated in the analytical pyrolysis studies. First, pyrolysis-gas chromatography-microwave induced atmospheric pressure helium emission spectroscopic detection (Py-GC-MED) was applied to the phosphazenes for element selective detection of carbon, phosphorus and halogens at three pyrolysis temperatures. Secondly, pyrolysis-gas chromatography-direct current argon plasma emission spectroscopic detection (Py-GC-DCP) was applied to the silarylene-siloxanes for element selection detection of silicon. Simultaneous carbon detection was accomplished by flame ionization detection (FID). The utility of both these plasma emission spectroscopic detectors for element selective fingerprint analysis of heteroatom containing polymers was demonstrated. Pyrolysis-gas chromatography-electron impact (EI) and chemical ionization (CI) mass spectrometry was used for the identification of pyrolysis products from both phosphazene and silarylene-siloxane polymers. A detailed degradation mechanism for poly{bis(2,2,2-trifluoroethoxy) phosphazene} was proposed based on the products observed. The presence of the D(,3), D(,4) and D(,5) dimethylcyclosiloxanes in the pyrolysis products of the silarylene-siloxane polymers indicated that intermolecular rearrangment of siloxane portions of the polymers most likely occurred. The results of this work illustrate the broad range of useful data obtainable using thermal analysis, element selective detection and mass spectrometry together in polymer pyrolysis studies.

A study of the halogenated organics derived from the chlorination of Humic acid in the presence of bromide was undertaken. The analysis involved liquid-liquid extraction with ether of the neutral (pH 7) and acidic (pH 1) fractions of the humic solution, followed by identification of the compounds by Gas Chromatography with Electron Capture (ECD), Microwave Induced Helium Plasma (single channel (MIP) and multichannel (MMIP)) and Mass Spectroscopy (MS). Amherst drinking water was also analyzed. Parameters of pH, Cl/Br ratio, and time were investigated in humic acid chlorination (with bromide) to determine effects upon Trihalomethane (THM) formation. The effect of chloramination upon THM study vs. chlorination was also examined. GC-MS was used to identify compounds formed from Humic acid and in tap water. Selected spectra and interpretations are included. Five halogenated compounds in water were identified using GC-MS. GC-MIP and GC-MMIP were used to identify halogenated compounds by monitoring chlorine, bromine and carbon emission lines singly and simultaneously. From this empirical formulae for halogenated compounds were deduced. From all of these methods over 15 halogenated compounds have been identified from the chlorination of Humic acid and ten of these have been found to occur in finished drinking water. They are: chloroform (100 ppb), bromodichloromethane (8 ppb), dichloroacetonitrile (4 ppb), chlorodibromomethane (1 ppb) and bromoform (2 ppb). Trichloroacetic acid (100 ppb), dichloroacetic acid (10 ppb) and chlorodibromoacetic acid (1 ppb) were found in the acidic fraction. Trichloroacetaldehyde and trichloroacetone were also found but not quantitated.

The wide application of the different inductively coupled plasma (ICP) techniques commonly available has demonstrated that these methods of excitation and analysis can be reliably used for qualitative and quantitative applications. The enclosed inductively coupled plasma (EICP) adds to the advantages of the conventional ICP some unique features, such as wide operation pressure range, low sample consumption, and capability for the analysis of reactive and/or highly toxic materials. The EICP can be used in two modes: sealed and flowing. In the sealed configuration the gas flow through the container is stopped after the plasma discharge is established, and the plasma is sustained with only the gas inside the container. None of the approaches previously available provided an accurate representation of experimental EICP discharges or used all the predictive capabilities that a modeling technique can give to the evaluation of a plasma discharge. Therefore, the comprehensive modeling of the EICP configuration through the adaptation of existing models and development of new approaches was undertaken as the main goal of the present work. Once the model was developed it was tested and applied to the characterization of different experimental conditions important to the study of the EICP and its possible applications and optimization.

In the area of biomolecular separations, capillary electrophoresis (CE) is advantageous in terms of analysis speed, peak efficiency and small sample size requirements. In order to more fully assess the capabilities and limitations of this bio-analytical technique, CE was applied to a clinical, to a biological and to a practical research problem. In the area of clinical analyses, CE was used to determine qualitatively and quantitatively oxalate in various parenteral nutrition solutions. It was hypothesized that parenteral nutrition solutions act as direct sources of oxalate introduction into premature infants. The formation of oxalate stones in the renal glands of premature infants is becoming an increasing apparent clinical problem. A coelectroosmotic CE analytical method based on indirect UV detection was developed that could reliably measure oxalate at part-per-million (ppm) levels in commercial parenteral nutrition solutions. The results from the oxalate determinations indicated that the infusion of parenteral nutrition solutions into premature infants places a clinically significant and unnecessary oxalate burden on the infants. The CE characterization of biosynthetic membrane protein samples is a formidable analytical task. This is mainly due to the fact that intrinsic membrane proteins are extremely hydrophobic, and thus, difficultly soluble in the common aqueous based CE run buffers. In this biologically oriented separation problem, a counterelectroosmotic CE method (CZE) was developed to characterize samples of the transmembrane serine receptor protein. Qualitative electrophoretic profiles of the protein samples were made possible by the inclusion of sodium dodecyl sulfate (SDS) in the run buffer. The utility of CE as a basic analytical technique was applied to the separation and determination of short-chain dicarboxylic acids (succinic, glutaric and adipic acids) in saturated aqueous solutions. In order to gather basic aqueous solubility data for a homologous series of dicarboxylic acids, a practical separation of succinic, glutaric and adipic acids was developed and optimized. The detection of the dicarboxylic acids was based on indirect UV absorbance. The solubility determinations for the dicarboxylic acids showed close agreement with the reported literature values.

As electronic cigarettes become more prevalent in society, their use as a delivery mechanism for drugs of abuse has increased. Electronic cigarette liquids present a complex matrix due to the lack of regulation, and therefore standardization, in their manufacturing. Due to the lack of published data, development of new analytical methods to accommodate this complexity was deemed necessary. Gas chromatography-mass spectrometry (GC/MS) and liquid chromatography-tandem mass spectrometry (LC/MS/MS) methods were developed to identify the flavorants of the electronic cigarette liquids as well as identify and quantify nicotine and common drugs of abuse used with these devices. Seven drugs of abuse were investigated: methamphetamine, heroin, cocaine, fentanyl, JWH-081, JWH-018, and AM-2201. Electronic cigarette liquids from five manufacturers were sampled. From each manufacturer five "flavors" of liquids were chosen. Each liquid "flavor" was tested at the manufactures reported nicotine concentrations of 0 mg/mL, 12 mg/mL, and 24 mg/mL to give a total of 75 electronic cigarette liquid samples. Liquid-liquid extraction was performed on all samples prior to analysis by GC/MS and LC/MS/MS. Analysis was performed in replicates of five to identify the electronic cigarette liquid components as well as quantify nicotine and the four analytes of interest. For any electronic cigarette liquid labeled as containing 0 mg/mL of nicotine in which nicotine was identified, the sample was analyzed by GC/MS to quantify the nicotine level. These concentrations were compared to the naturally occurring levels of nicotine found in certain food products. Identification of the flavorants of the electronic cigarette liquids as well as the quantitation of nicotine and the four commonly abused drugs was accomplished using GC/MS and LC/MS/MS. Samples of e-liquids labeled by the manufacturer as containing 0 mg/mL of nicotine may contain detectable and quantifiable levels of nicotine. Quantitation of drugs of abuse may be affected by matrix components and was found to be dependent on both the specific e-liquid being used with the electronic cigarette as well as the analyte being investigated.

Bibliography: p. 262-274. / An X-ray crystal structure detennination of 3-nitro-l,5-di(2,6-dimethylphenyl) fonnazan, ArN:N•C(N02):N•NHAr (Ar= 2,6-dimethylphenyl), has shown that the N-N-C-N-N chain is stabilized by an unusual hydrogen bond in the closed-ring syn,s-cis configuration relative to the formal double C=N and single C-N bonds. The bond lengths reveal complete n-electron delocalization along the chain which results in a mesomeric structure; the possibility of such a mesomeric structure existing in solution rather than a rapid tautomeric equilibrium between two limiting forms of the resonance hybrid has been considered in the light of i.r. and n.m.r. spectroscopic measurements. The temporal changes in the visible absorption spectrum of S-methyldithizone, PhN:N•C(SCH3):N•NHPh, have been shown to arise from syn-anti isomerization about the fonnal C=N double bond and rotation about the C-N single bond by considering the evidence provided by i. r. and n.m.r. spectroscopic studies combined with the X-ray crystal structure of the di(o-tolyl) homologue. The parent compound dithizone, PhN:N•C(SH):N•NHPh, previously thought to exist as an equilibritim of thiol and thione forms in solution has now been shown to consist of a single species in solution mainly by consideration of its n.m.r. spectroscopic properties. Organomercury(II) complexes of dithizone have been shown to be photochromic in solution; X-ray crystal structure detenninations of phenyland methylmercury(II) dithizonate, besides revealing rare three-coordination of mercury, have been combined with spectroscopic measurements on the normal and activated fonns to reveal the structure of the labile photo-isomers.