The purpose of this research is to improve the performance of Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) by way of a study of the sources of limiting performance. This is demonstrated with the use of practical diagnostics and new ICP-OES instrumentation having a cross-dispersed echelle spectrometer and a matched segmented-array charge coupled device detection system. The main finding of this work is that the advanced detection system can be coupled with multivariate data processing to reduce analytical precision and detection limit values to their fundamental limits. Practical diagnostic protocol enables elucidation of the factors governing these important figures of merit in ICP-OES. A key diagnostic method used in this work is the signal to background ratio - relative standard deviation of the background (SBR-RSDB) approach developed by Boumans for detection limit studies. This methodology serves as the framework to compare detection limits and understand the physical basis for improvements or differences. The SBR-RSDB approach was used to show how multivariate methods take advantage of the simultaneous multielement spectral registration of the new instrumentation. The combination of simultaneous spectral readout and multivariate processing yields detection limits which are reduced to the photon shot noise limit, even when source flicker noise is dominant in the background signal. Other demonstrated advantages of multivariate methods are the capability for spectral interference correction and automatic background correction superior to conventional methods. The SBR-RSDB approach was central to understanding the performance differences between axial and radial viewing of the inductively coupled plasma. Real-time internal standardization is demonstrated to improve precision values to the photon shot noise limit. For certain elements, a barrier to the achievement of shot noise limited precision was identified and linked to differences in the noise signatures of the reference and analyte signals. The magnitudes of the noise in the signals were strongly related to excitation energy for atomic lines. An explanation in terms of the influence of incompletely vaporized droplets in the observation volume is proposed which is consistent with the observed results.

The overall objective of this thesis has been to improve the performance characteristics of analytical atomic spectrometers using on-line flow based front-end chemistry and various separation schemes with minimum or no physical modification of the instrument. The underlying philosophy was to develop methods which were rapid, and easy to operate using the minimum amounts of sample and reagent and which generated the minimum amount of waste and were amenable to automation. A method for the on-line preconcentration of copper was developed. This method uses a precipitation and dissolution approach and the manifold was directly coupled to an atomic absorption spectrometer. Using a novel semi-automated flow injection manifold design an order of magnitude improvement in detection limit over conventional aspiration was obtained. Using a precipitation reaction, potentially hazardous material was removed on-line from samples before their introduction into the spectrometer. There was a kinetic limitation of the reaction involved in this method, but using a recirculating loop manifold this was overcome and the method was successfully applied to the on-line determination of various trace metals in solutions containing high amounts of silver. A flow injection method for the rapid on-line determination of trace metals in solutions containing high concentrations of sodium nitrate was developed. This method was developed as fast diagnostic procedure using special in-line mixers to dilute the samples on-line and thereby reduce the effect of the matrix. The method was successfully applied to samples obtained from the Royal Canadian Mint. Using flow injection sample introduction and inductively coupled plasma-mass spectrometry detection the determination of mercury was achieved using a gas/solid reaction. The approach was to generate a cold vapor of mercury, by reaction with a reductant, and trapping it on a gold/platinum gauze and releasing it by controled heating and passing it to the ICP-MS for detection and quantification. This method was successfully applied to a variety of water samples. Matrix effects were reduced and sensitivity and detection limit were improved. A study of solid/liquid reactions for the on-line matrix separation and preconcentration of trace elements in sea water was carried out. The method involved on-line adjustment of the pH of the sample solutions and then passing the sample over an ion-exchange chelating resin. The analytes were retained on the resin and the matrix was washed away to waste. The analytes were removed from the resin with acid and introduced into the ICP-MS for detection and quantification. This sample cleanup procedure was successfully applied to the determination of several trace elements in spiked sea water standard reference materials.

<p>Ambient concentrations of polycyclic aromatic compounds [PAC], other air pollutants and the mutagenic potency of respirable air particulate extracts were used to study air quality in Hamilton from May of 1990 to June of 1991. Concentrations of polycyclic aromatic hydrocarbons [PAH], thiaPAH, oxygenated PAC and in some cases nitroPAH as well as the mutagenic activity caused by these compounds were determined in 68 samples of air particulate, collected over a number of days with widely varying air pollutant concentrations and atmospheric conditions. Chemical analyses of the non-polar aromatic fractions of the air particulate extracts showed a 550-fold range in PAC concentrations, from 0.31 to 170 ng/cubic metre air, while biological assays showed a 140-fold range of mutagenic potencies. The non-polar aromatic fraction represented about three-quarters of the sum of the mutagenic responses in the polar and non-polar aromatic fractions. The mutagenicity and PAC concentrations of air particulate collected in Hamilton are low to average compared to air particulate samples collected in other cities around the world. Relationships between mutagenic potencies, PAC concentrations and atmospheric condistions were examined using principal component analysis, which revealed good positive correlation between the mutagenic potencies of the non-polar aromatic fractions, nitrogen diozide and sulfur dioxide concentrations. Average windspeed and ozone concentrations were inversely correlated with mutagenicity. Principal component analysis also show that sprigtime thermal inversion episodes correlated with conditions favoring the atmospheric transformation of PAH to mutagenic nitroPAH. The mutagenic potency of the non-polar aromatic fraction of air particulate extract rose in direct proportion to nitroPAH concentrations arising from atmospheric transformation. Enhanced-sensitivity strains of Salmonella typhimurium were used in all bioassays of air particulate extract mutagenicity, thereby making more extract available for extensive chemical analyses. For example, bioassay analyses of a pooled sample of air particulate extract were carried out using six different strains of S. typhimurium. Strains containing increased levels of enzymes responsible for metabolizing compounds such as nitroPAH showed 7- to 10-fold enhance mutagenic responses compared to standard tester strains. Normal-phse HPLC seperation of the non-polar aromatic fraction of the pooled air particulate extract was combined with bioassays utilizing three different enhanced-sensitivity S. typhimurium strains, allowing quantitation of individual mutagens through analytical chemical methods as well as accurate determination of the mutagenic activity arising from each compound. Normal-phase HPLC separation was also used in the bioassay-directed fractionation of an extremely mutagenic air particulate sample collected at the side of Highway 404 in Toronto, Ontario. NitroPAH arising from combustion sources were determined to be responsible for virtually all of the mutagenic activity detected in this particular sample, from which was isolated a potent mutagen not previously described in air particulate extracts -3.8-dinitrofluoranthene.</p> / Doctor of Philosophy (PhD)

<p>This thesis embodies an investigation into the structure and thermal isomerizations of retinylidene iminium salts and related systems. Over the past three decades there has been a tremendous amount of interest surrounding the structurally related natural pigments rhodopsin and bacteriohodopsin. Studies of these compounds have had a large impact in the fields of bioenergetics and visual photochemistry. Both of these proteins consist of a protonated Schiff base linkage between the retinal chromophore and the protein. A series of retinylidene iminium salts were synthesized and characterized both in solution and the solid state. A unique combination of x-ray crystallography, solid state $\sp{13}$C NMR, FTir and uv spectroscopic techniques were used in order to address the mechanism by which the protein can modify the electronic properties of the retinal chromophore in the ground state. One important conclusion of this study was that wavelength and positive charge delocalization in retinylidene iminium salts can primarily be modified by varying the distance between the anion and the proton bonded to the Schiff base nitrogen atom. It was also found that most of the positive charge in these systems is located on the nitrogen atom and the proton to which it is bonded. The thermal cis-trans isomerization about the C11-C12 bond of a series of retinylidene iminium salts was investigated by high field $\sp1$H NMR spectroscopy at ambient temperatures. It was found that the isomerizations proceeded via nucleophilic catalysis by the counterion present in the salt. No 11-cis isomer was detected at thermodynamic equilibrium for all of the salts examined. The thermal reactivity of the isoelectronic protonated poly-unsaturated aldehydes were also examined by high field $\sp1$H NMR spectroscopy. In contrast to the observed iminium salt chemistry, it was found that these species cyclized completely in superacidic media to form cyclopentene ring moieties. It was found that the rate determining step in these reactions involves additional protonation on the oxygen atom to form a dication.</p> / Doctor of Philosophy (PhD)

Biological detectors, such as canines, are valuable tools used for the rapid identification of illicit materials. However, recent increased scrutiny over the reliability, field accuracy, and the capabilities of each detection canine is currently being evaluated in the legal system. For example, the Supreme Court case, State of Florida v. Harris, discussed the need for continuous monitoring of canine abilities, thresholds, and search capabilities. As a result, the fallibility of canines for detection was brought to light, as well as a need for further research and understanding of canine detection. This study is two-fold, as it looks to not only create new training aids for canines that can be manipulated for dissipation control, but also investigates canine field accuracy to objects with similar odors to illicit materials. It was the goal of this research to improve upon current canine training aid mimics. Sol-gel polymer training aids, imprinted with the active odor of cocaine, were developed. This novel training aid improved upon the longevity of currently existing training aids, while also provided a way to manipulate the polymer network to alter the dissipation rate of the imprinted active odors. The manipulation of the polymer network could allow handlers to control the abundance of odors presented to their canines, familiarizing themselves to their canine’s capabilities and thresholds, thereby increasing the canines’ strength in court. The field accuracy of detection canines was recently called into question during the Supreme Court case, State of Florida v. Jardines, where it was argued that if cocaine’s active odor, methyl benzoate, was found to be produced by the popular landscaping flower, snapdragons, canines will false alert to said flowers. Therefore, snapdragon flowers were grown and tested both in the laboratory and in the field to determine the odors produced by snapdragon flowers; the persistence of these odors once flowers have been cut; and whether detection canines will alert to both growing and cut flowers during a blind search scenario. Results revealed that although methyl benzoate is produced by snapdragon flowers, certified narcotics detection canines can distinguish cocaine’s odor profile from that of snapdragon flowers and will not alert.

Heavy metals are a recognized toxic environmental contaminant, even at very low concentrations. There have been well-known events in the last decade within the US of high amounts of lead in the drinking water supplies of cities, leading to detrimental effects within its population. Ways have been found to remove this metal, and others, from water with expensive adsorbents. The aim of the first part of this research was to create an inexpensive adsorbent from a waste material and modify it in such a way that it would be adept at removing heavy metals from water. In Chapter I, we were able to remove lead, copper, and cadmium using our peanut shell-based activated carbon, getting a high amount of metal adsorption when the activated carbon was activated with phosphoric acid, pyrolyzed, and then cooled under a nitrogen atmosphere. The activated carbon was characterized and found to have a BET surface area of 781 m2g-1 and a Langmuir maximum isotherm capacity of 100.2 mg/g. By using the data obtained in this work, it could lead to the development of further economically made adsorbents to be used to provide more people with clean drinking water. The second part of our work focused on the benefit of a hands-on approach to chemical education. In Chapter IV, we discuss the development and implementation of our NSF-funded summer research experience for undergraduates program, as well as the student-reported results from their 10-week research experience. These surveys showed consistent self-reported growth among the student cohort in the skill sets that were focused on during the program. Chapter V focuses on the development, application, and analysis of results for a novel home-based laboratory component for a semester-long organic chemistry course. It featured 12 lab activities: 8 hands-on experiments and 4 online modeling exercises. By developing and sharing this off-campus approach, we hope to provide an option for other universities that are looking for at-home laboratory experiences for their own students. Overall, we found that these approaches to experiencing chemistry in a hands-on way were beneficial to students and provided them with a greater interest in chemistry.

<p>The work in this thesis encompasses (a) the development of a robust analytical method suitable for the comprehensive analysis of polar and non-polar metabolites in a single analysis and (b) the application of this method to the study of the metabolites involved in peanut allergy. During the course of this work the methods for the analysis of large metabolite data sets evolved significantly and the approaches used in this work evolved in parallel to the literature. This work constitutes the first comprehensive metabolomic investigation of an allergy response.</p> <p>Hypersensitivity or allergy to peanuts is an increasingly problematic health concern around the world involving approximately 1-2% of children in North America. There are no useful clinical biomarkers for this allergy. Comprehensive metabolomics holds vast potential for the discovery of metabolites and metabolite pathways that may be involved during the development of peanut allergy and during peanut-induced anaphylaxis. The comprehensive study of metabolites involved in peanut allergy presented a significant challenge since no single analytical technique is capable of analysis of all metabolites within a single analytical run.</p> <p>The thesis begins with development of a tandem column liquid chromatography-electrospray ionization-mass spectrometry method which allowed the separation and analysis of both polar and non-polar metabolites in a single analysis. This tandem column technique was also shown to significantly reduce the amount of ion suppression observed compared to the ion suppression observed when using either column independently.</p> <p>This methodology was applied to the comprehensive metabolomics analysis of blood serum samples obtained from mice which were (a) being sensitized to peanuts and (b) undergoing anaphylaxis. This analysis discovered a profound impact on metabolites involved with purine metabolism, resulting in an elevation of uric acid levels. This discovery led to further investigations which confirmed that uric acid is essential for peanut sensitization in mice. This discovery was only possible due to the use of a comprehensive metabolomics approach.</p> <p>The analytical methodology was then applied to the study of metabolomic changes in sensitized mice as they experienced peanut-induced anaphylaxis. A number of metabolomic changes including taurine level elevation were correlated with peanut-induced anaphylaxis. Finally, a serendipitous opportunity arose to analyze blood serum samples from peanut allergic children that had undergone an oral peanut challenge. The comprehensive metabolomic study of these samples revealed massive changes in their serum metabolomes as a result of peanut exposure. A number of lipids and lysophospho-lipids were shown to have increased dramatically and may represent novel biomarker candidates for peanut-induced anaphylaxis in humans.</p> <p>In summary, this thesis had demonstrated that comprehensive metabolomic analyses can be successfully applied to complex syndromes such as peanut allergy and yield useful mechanistic and clinical insights to this disorder.</p> / Doctor of Philosophy (PhD)

<p> Detecting environmental contaminants such as Selective serotonin reuptake inhibitors (SSRIs) and Cr (VI) compounds is essential since they are highly toxic contaminants of many drinking water supplies leading to adverse health effects. Selective serotonin reuptake inhibitors are common antidepressants therapeutics and fluoxetine; Prozac^&reg;, citalopram; Celexa^&reg; and sertraline; Zoloft^&reg; were successfully detected in this study. Ion transfer stripping voltammetry (ITSV) was applied to detect those as cations at nanomolar concentrations using an inexpensive and disposable pencil lead electrode, with a lower detection limit of 30 nM. The pencil lead electrode was modified using the conducting polymer Poly (3, 4-ethylenedioxythiophene) (PEDOT-C14) and PVC (poly-vinyl chloride) membrane. The PVC/PEDOT-C₁₄ -modified electrode demonstrated a linear current response from 100 to 1000 nM for these therapeutics. Ion transfers of Hydrogen chromate as anions were studied using a double-polymer modified glassy carbon electrode using the conducting polymer poly (3-octylthiophene) (POT), and PVC membrane. Lipophilicity of Hydrogen chromate ions were evaluated comparing to other common inorganic contaminants. Exhaustive stripping of Hydrogen chromate ions in cyclic voltammetry and their relative high lipophilicity infer that ITSV can be successfully applied to detect them in future studies. </p>

<p> We have studied the pyrolysis of aromatic combustion intermediates using an array of detection techniques. The molecules investigated include cyclic aromatic molecules with hydrocarbon substituents (ethylbenzene, n-propylbenzene, isopropylbenzene, and styrene), oxygen-containing substituents (anisole and phenol), resonance stabilized radicals (benzyl radical and tropyl radical) and phenyl radical. At the exit of a resistively heated micro-reactor (1 mm inner diameter, 3 cm long), the pyrolysis fragments are detected using photoionization mass spectrometry (PIMS), matrix isolation vibrational spectroscopy, microwave spectroscopy, tunable VUV synchrotron-based PIMS, and tabletop VUV PIMS with photoelectron photoion coincidence spectroscopy (PEPICO). This array of detection methods allows for the identification of all possible fragments including metastables, radicals, and atoms. The findings allow for detailed mechanistic information regarding which pathways are active at different pyrolysis temperatures and can also be used to help identify products and individual isomers that are formed during the gas-phase thermal decomposition of aromatic systems. By providing direct experimental pyrolysis data, models for fuel decomposition and soot formation can be improved to help understand current combustion systems and eventually aid in the design of superior fuel sources in the near future.</p>

<p>Tropospheric fine particulate matter (PM) poses serious health risks and has a significant impact on global climate change. The measurement of various aspects of PM is challenging due to its complex chemical nature. This dissertation addresses various aspects of PM, including composition, measurement, and visibility. The U.S. Environmental Protection Agency (EPA) proposed a new secondary standard based on visibility in urban areas using 24-h averaged measurements of either light scatter or PM concentration. However shorter averaging times may better represent human perception of visibility. Data from two studies conducted in Lindon, UT, 2012, and Rubidoux, CA, 2003, were used to compare different techniques to estimate visibility, particularly the effect of relative humidity on visibility estimations. Particle composition was measured in Salt Lake City during January-February of 2009. One-hour averaged concentrations of several gas phase and particle phase inorganic species were measured. The results indicate ammonium nitrate averages 40% of the total PM2.5 mass in the absence of inversions and up to 69% during strong inversions. Also, the formation of ammonium nitrate is nitric acid limited, while the formation of ozone appears to be oxidant and volatile organic carbon (VOC) limited. Reduction of NOx will reduce ammonium nitrate secondary particle formation, however, a decrease in NOx may increase ozone concentration. </p><p> Due to the complexity of PM it is poorly characterized. A large fraction of PM is composed of organic compounds, but these compounds are not regularly monitored due to limitations in current sampling techniques. The GC-MS Organic Aerosol Monitor (OAM) combines a collection device with thermal desorption, gas chromatography and mass spectrometry to quantitatively measure the carbonaceous components of PM on an hourly averaged basis. A compact GC and simple pre-concentrator were developed for the system to decouple separation from manual injection and enhance separation of environmentally-relevant polar organic compounds, such as levoglucosan. The GC-MS OAM is fully automated and has been successfully deployed in the field. It uses a chemically deactivated filter for collection followed by thermal desorption and GC-MS analysis. Laboratory tests show that detection limits range from 0.2 to 3 ng for many atmospherically relevant compounds. The GC-MS OAM was deployed in the field for semi-continuous measurement of the organic markers, levoglucosan, dehydroabietic acid, and several polycyclic aromatic hydrocarbons (PAHs) during winter (January to March), 2015 and 2016. Results illustrate the significance of this monitoring technique to more fully characterize the organic components of PM and identify sources of pollution. </p><p> Keywords: air pollution, fine particulate matter, PM_2.5, secondary organic aerosol, organic markers, levoglucosan, PMF. </p>