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Electronic Theses and Dissertations

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Full-Text Articles in Chemistry

In Situ Treatment Systems For Remediation Of Polychlorinated Biphenyl-Contaminated Building Materials, Adibah Almutairi Jan 2018

In Situ Treatment Systems For Remediation Of Polychlorinated Biphenyl-Contaminated Building Materials, Adibah Almutairi

Electronic Theses and Dissertations

Polychlorinated Biphenyls (PCBs) are a family of synthetic organohalides comprising 209 congeners which were used historically as additives in paint and caulking materials over a span of many years. Even though the production of PCBs in the USA has been banned since the late 1970s, their former prevalence and widespread use means many structures are still coated with PCB-laden paints. In addition, the presence of PCBs in elastic sealants has resulted in transport of PCBs into concrete structures and has caused soil contamination around buildings. PCB-contaminated building materials have become a significant concern for the environment and building occupants due …


Light Scattering Property Of Gold Nanoparticles With Applications To Biomolecule Detection And Analysis, Tianyu Zheng Jan 2018

Light Scattering Property Of Gold Nanoparticles With Applications To Biomolecule Detection And Analysis, Tianyu Zheng

Electronic Theses and Dissertations

Gold nanoparticles (AuNPs) have unique optical and chemical properties. Dynamic light scattering (DLS) is an analytical tool used routinely for nanoparticle size measurement. The combined use of AuNPs and DLS has led to a novel analytical assay technology called D2Dx (from diameter to diagnostics). Herein, my dissertation highlights the extended use of D2Dx for biomolecule detection and analysis. Under this general theme, Chapter 1 provides some background information of AuNPs, DLS, the principle of D2Dx technique and its potential applications. Chapter 2 summarizes a study on the effect of AuNP concentrations and laser power on the hydrodynamic size measurement of …


Synthesis And Evaluation Of Dual-Acting Ligands For Mu Opioid And Neuropeptide Ff Receptors, Kelsey Gabrielle Mcpherson Jan 2018

Synthesis And Evaluation Of Dual-Acting Ligands For Mu Opioid And Neuropeptide Ff Receptors, Kelsey Gabrielle Mcpherson

Electronic Theses and Dissertations

Pain, although subjective, is an unpleasant sensation caused by a noxious stimulus, that effects millions of people every year. Currently, the most frequently prescribed class of analgesics for moderate to severe acute and sometime chronic pain are opioid analgesics, most commonly ?-opioid receptor (MOP) agonists, such as oxycodone, morphine, and fentanyl. Although these drugs provide significant pain relief, they are also associated with unwelcome side effects such as constipation, addiction, physical dependence, respiratory depression, and physiological tolerance that leads to hyperalgesia. Receptor desensitization due to excessive receptor activation by an agonist is but one source of physiological tolerance; it can …


Optical Properties Of Single Nanoparticles And Two-Dimensional Arrays Of Plasmonic Nanostructures, Yadong Zhou Jan 2018

Optical Properties Of Single Nanoparticles And Two-Dimensional Arrays Of Plasmonic Nanostructures, Yadong Zhou

Electronic Theses and Dissertations

The tunability of plasmonic properties of nanomaterials makes them promising in many applications such as molecular detection, spectroscopy techniques, solar energy materials, etc. In the thesis, we mainly focus on the interaction between light with single nanoparticles and two-dimensional plasmonic nanostructures using electrodynamic methods. The fundamental equations of electromagnetic theory: Maxwell's equations are revisited to solve the problems of light-matter interaction, particularly the interaction of light and noble nanomaterials, such as gold and silver. In Chapter 1, Stokes parameters that describe the polarization states of electromagnetic wave are presented. The scattering and absorption of a particle with an arbitrary shape …


Development And Characterization Of Solid-Contact Paper-Based And Micro Ion-Selective Electrodes For Environmental Analysis, Stephanie Armas Jan 2018

Development And Characterization Of Solid-Contact Paper-Based And Micro Ion-Selective Electrodes For Environmental Analysis, Stephanie Armas

Electronic Theses and Dissertations

Ion-selective electrodes (ISEs) have extensively been used for food analysis, as medical diagnostic tools, and for some environmental applications. However, ISEs are hindered by the need of a bulky reference electrode and the pre-conditioning step of the sensor, which can often be lengthy. This work will discuss how the direct addition of target analyte into the cocktail sensing membrane can circumvent the pre-conditioning step. Furthermore, the work is presented in an optimized ready-to-use single strip design, where the bulky glass reference electrode (RE) is no longer needed. The bulky RE was replaced by drop casting a simple two-component mixture consisting …


Advancements In Liquid Chromatography For The Determination Of Polycyclic Aromatic Compounds In Environmental Samples, Hugh Hayes Jan 2018

Advancements In Liquid Chromatography For The Determination Of Polycyclic Aromatic Compounds In Environmental Samples, Hugh Hayes

Electronic Theses and Dissertations

The purpose of this dissertation is to provide a new and improved analytical methodology for the analysis of polycyclic aromatic hydrocarbons (PAHs) and polycyclic aromatic sulfur heterocycles (PASHs) in environmental samples. Hundreds of PAHs and PASHs are present in the environment and have great toxicological importance and the chemical determination of these components is a priority. The complete normal-phase liquid chromatography (NPLC) retention behavior has been explored for these compounds. Retention indices were determined for 124 PAHs, 62 methyl-PAHs (MePAHs), 67 PASHs, and 80 alkyl-PASHs on an aminopropyl (NH2) stationary phase which represents the most comprehensive study of polycyclic aromatic …


Design, Synthesis, Stability, And Photocatalytic Studies Of Sustainable Metal-Organic Frameworks, Matthew Logan Jan 2018

Design, Synthesis, Stability, And Photocatalytic Studies Of Sustainable Metal-Organic Frameworks, Matthew Logan

Electronic Theses and Dissertations

The presented dissertation focuses on the design, synthesis, and characterization of metal-organic frameworks (MOFs) composed of earth-abundant elements the exhibit photoredox activity and studied their application as heterogeneous photocatalysts in organic synthesis and in solar-to-chemical energy conversion. In particular, the structure-property relationships of titanium-based MOFs relating the structure of the organic building unit and the photophysical and photochemical activity of the solid material is studied. The first novel family of seven MOFs isoreticular to MIL-125-NH2, includes functionalized with N-alkyl groups with increasing chain length (methyl to heptyl) and with varying connectivity (primary or secondary). The functionalized materials displayed reduced optical …


Qualitative And Quantitative Elemental Composition Analysis Of The Surrounding Pollen Coating Via Icp-Ms, Brandy Voyer Jan 2018

Qualitative And Quantitative Elemental Composition Analysis Of The Surrounding Pollen Coating Via Icp-Ms, Brandy Voyer

Electronic Theses and Dissertations

Pollen evidence has proven to be a powerful forensic tool to trace a suspect or item to a victim or a crime scene. This is possible because it is microscopic, abundant in nature, resistant to degradation and decay; it presents dispersal patterns that can be used to generate a 'fingerprint' within specific areas, and has illustrated a unique morphology that can be used to classify species. While the pollen grain morphology has been extensively used to characterize the specific species, not much has been investigated as pertains to the coating that surrounds the pollen grain aside from it being categorized …


Integration Of Fundamental Research And Cer: The Role Of Authenticity In Developing Views On The Nature Of Teaching, Learning, And Doing Science, Julie Donnelly Jan 2018

Integration Of Fundamental Research And Cer: The Role Of Authenticity In Developing Views On The Nature Of Teaching, Learning, And Doing Science, Julie Donnelly

Electronic Theses and Dissertations

This dissertation is an integration of fundamental research and chemical education. It begins with two nonlinear spectroscopic studies of compounds important to the study of brain chemistry. In Chapter 2, we present a novel method using quantum mechanics for modelling ligand docking and the potential of nonlinear circular dichroism for elucidating the mechanism of cannabinoids docking to their receptor, a contribution to studies of varying psychological effects of cannabinoids. Considering existent challenges with measuring this phenomenon, in Chapter 3, we evaluate two-photon absorption properties of Thioflavin T (ThT) in varying glycerol/water content solutions and discuss the enhancement of nonlinear absorption …


Nanoscale Characterization And Mechanism Of Electroless Deposition Of Silver Metal, Christopher Grabill Jan 2018

Nanoscale Characterization And Mechanism Of Electroless Deposition Of Silver Metal, Christopher Grabill

Electronic Theses and Dissertations

This dissertation is an investigation of the nanoscale characteristics and mechanism of electrolessly deposited silver metal seeded by gold nanoparticles. The process of growing seed-nanoparticles on a polymer surface was studied. Several bifunctional amines and organic reducing agents were used to explore how these chemical factors affect the size and distribution of gold nanoparticles formed at the interface. The nanoparticles were characterized by transmission electron microscopy (TEM) and high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM). An electroless deposition (ED) bath developed by Danscher was selected to study electroless deposition of silver in detail. The chemical species in the bath …


Split Aptameric Turn-On Fluorescence Sensor For Detection Of Sequence Specific Nucleic Acid At Ambient Temperature, Nanami Kikuchi Jan 2018

Split Aptameric Turn-On Fluorescence Sensor For Detection Of Sequence Specific Nucleic Acid At Ambient Temperature, Nanami Kikuchi

Electronic Theses and Dissertations

Nucleic acid amplification tests (NAATs) enable sensitive detection of low density infections that microscopy and rapid diagnostic test are not capable of detecting. They enable quantitative and qualitative nucleic acid detection, genotype analysis, and single nucleotide polymorphism (SNP) detection. Current state of the art molecular probes used with NAATs includes molecular beacon (MB), Taqman and its variations. This work presents novel molecular probe designed from Spinach and Dapoxyl aptamers. The aptamers are split into two parts (split aptamer), allowing greater sensitivity and selectivity towards fully complementary nucleic acid analyte. The major advantage of split aptamer probe over state-of-the-art fluorescent probes …


Artificial Olfactory System For Multi-Component Analysis Of Gas Mixtures., Alexander Aleksandrovich Larin Dec 2017

Artificial Olfactory System For Multi-Component Analysis Of Gas Mixtures., Alexander Aleksandrovich Larin

Electronic Theses and Dissertations

Gas analysis is an important part of our world and gas sensing technology is becoming more essential for various aspects of our life. A novel approach for gas mixture analysis by using portable gas chromatography in combination with an array of highly integrated and selective metal oxide (MOX) sensors has been studied. We developed a system with small size (7 x 13 x 16 inches), low power consumption (~10 W) and absence of special carrier gases designed for portable field analysis (assuming apriori calibration). Low ppb and even sub-ppb level of detection for some VOCs was achieved during the analysis …


Study Of 2,5-Diaminoimidazolone, A Mutagenic Product Of Oxidation Of Guanine In Dna, Hannah Catherine J. Pollard Dec 2017

Study Of 2,5-Diaminoimidazolone, A Mutagenic Product Of Oxidation Of Guanine In Dna, Hannah Catherine J. Pollard

Electronic Theses and Dissertations

2,5-diaminoimidazolone (Iz) is an important product of a 4-electron oxidation of guanine. The present research focuses on the mechanisms of formation of Iz via pathways initiated by guanine oxidation by one-electron oxidants (OEOs) generated by X-ray radiolysis in aqueous solutions. The kinetics of formation and yields of Iz in reactions of native highly polymerized DNA with different OEOs have been compared using an HPLC-based quantitative analysis of low-molecular products generated from the reaction of DNA-bound Iz with primary amines. Mechanisms of Iz formation in DNA have been investigated including oxygen and superoxide dependence as well as the hypothesis that 8-oxo-G, …


Evaluating Ligand Assisted Activation Of Small Molecules Through Proton Reduction And Alcohol Oxidation., Rahul Jain Dec 2017

Evaluating Ligand Assisted Activation Of Small Molecules Through Proton Reduction And Alcohol Oxidation., Rahul Jain

Electronic Theses and Dissertations

Hydrogen is a potential alternate to the carbon fuels to meet the future demands for energy in an eco-friendly manner. Hydrogen produced by the electrolysis of water is stored in fuel cells which on demand can be converted into electrical energy upon the reaction with oxygen. In the quest for economically viable electrocatalysts for hydrogen evolution, the work in this dissertation describes evaluation of nickel based catalysts coordinated to redox active ligands, dialkyl/diarylphosphine benzenethiol and bis(thiosemicarbazone) for their ability to generate hydrogen with external acids as a proton source. A nickel complex with the benzenethiol ligand framework follows a traditional …


Chemoselective Reagents For Derivatization Of Trace--Level Volatile Carbonyl Compounds Using A Microreactor Approach., Mumiye A. Ogunwale Dec 2017

Chemoselective Reagents For Derivatization Of Trace--Level Volatile Carbonyl Compounds Using A Microreactor Approach., Mumiye A. Ogunwale

Electronic Theses and Dissertations

Detection and analysis of trace level volatile aldehydes and ketones has become a significant research frontier because of the applicability for environmental monitoring and assessment, noninvasive diseases diagnosis, and in food safety assessment for the US Food and Drug Administration. The number of derivatization reagents for detection of aldehydes and ketones has increased considerably over the last decade. However, the majority of these derivatization reagents are not efficient in derivatizing unsaturated carbonyl compounds due to the presence of electron withdrawing groups adjacent to the reactive functional moieties making them insufficiently nucleophilic. The analysis of trace-level carbonyl compounds challenges existing analytical …


A Novel Method For Synthesis Of Hydroxytyrosol, Emmanuel Onobun Aug 2017

A Novel Method For Synthesis Of Hydroxytyrosol, Emmanuel Onobun

Electronic Theses and Dissertations

Hydroxytyrosol, 3,4-dihydroxyphenolethanol, a naturally occurring polyphenol most common in olive tree (Olea europaea), is one of the most effective member of the polyphenols family, because of its remarkable antioxidant activity, its ability to inhibit oxidation of low density lipids (LDL), and its protection against DNA oxidative damage. Hydroxytyrosol, which is widely used in cosmetics and food supplements industries, can be purchased as an olive oil extract that contains low concentration of hydroxytyrosol besides other polyphenols. The price and low natural abundance of hydroxytyrosol make alternative synthetic sources very attractive. In this research, a novel method for the synthesis of pure …


Water-Soluble Pd And Pd-Alloy Nanoparticles As Catalysts In Biphasic Solvent., Shekhar Bhama Aug 2017

Water-Soluble Pd And Pd-Alloy Nanoparticles As Catalysts In Biphasic Solvent., Shekhar Bhama

Electronic Theses and Dissertations

This dissertation shows the chemical synthesis of Pd and Pd-alloy nanoparticles (NPs) and their hydrogen and thermal stabilities for applications in the homogeneous and pseudo-homogeneous catalysis of organic reactions. Mainly, this dissertation describes 1) the chemical synthesis of Pd, PdPt, PdAu and Cu-Pd core-shell NPs coated with various organic ligands (thiols, amines and citrate), with different metal compositions in different synthetic environment, 2) the stability of solutions containing various NPs in the presence of hydrogen or varying temperatures, 3) the evaluation of the catalytic activity of Pd, PdPt, PdAu and CuPd NPs for hydrogenation/isomerization of allylic alcohols, and 4) the …


Controlled Electrochemical Synthesis Of Single One-Dimensional Metal Nanochains Across Microgap Electrodes., Amareshwari Konutham Aug 2017

Controlled Electrochemical Synthesis Of Single One-Dimensional Metal Nanochains Across Microgap Electrodes., Amareshwari Konutham

Electronic Theses and Dissertations

This study mainly focuses on the fabrication of single one dimensional (1D) NP chains across the 5-micron gap of Au two electrode devices (TED). This has been achieved by electrochemical deposition of Ag onto the two electrodes, soaking the TED in 0.1 M Cetyltrimethyl ammonium bromide for 2-3 hours, and then close monitoring of the current as a function of time while a voltage across the two Ag coated Au electrodes in air. One dimensional Ag nanoparticle chain formation occurred by oxidation of Ag to Ag+ at the positive electrode followed by movement of Ag+ ions to the …


Transient Absorption Studies Of Cdse Nanocluster Passivated With Phenyldithiocarbamate Ligands., Yizhou Xie Aug 2017

Transient Absorption Studies Of Cdse Nanocluster Passivated With Phenyldithiocarbamate Ligands., Yizhou Xie

Electronic Theses and Dissertations

Semiconductor nanocluster (SCNC) research is a rapidly growing field driven by the promising fact that properties of such materials can be tailored by modifying their size, shape, and structure. Combination of nanocluster and organic ligands provides even wider possibilities of design and development of effective and task-specific nanostructures. Understanding of and, eventually, control of energetics, interfacial interaction, and photoinduced processes in such highly heterogeneous structures is critical to invention of novel materials including those in photovoltaic devices. In the newly established Ultrafast Laser Facility (ULF), transient absorption pump-probe spectroscopy (TAPPS) has been employed to investigate the electron transfer (ET) and …


Ab Initio And Semi-Empirical Calculations Of Cyanoligated Rhodium Dimer Complexs, Yazeed Asiri May 2017

Ab Initio And Semi-Empirical Calculations Of Cyanoligated Rhodium Dimer Complexs, Yazeed Asiri

Electronic Theses and Dissertations

Molecular modeling, using both ab initio and semi-empirical methods has been undertaken for a series of dirhodium complexes in order to improve the understanding of the nature of the chemical bonding in this class of homogeneous catalysts. These complexes, with carboxylamidate and carboxylate ligands, are extremely functional metal catalysts used in the synthesis of pharmaceuticals and agrochemicals. The X-ray crystallography shows anomalies in the bond angles that have potential impact on understanding the catalysis. To resolve these issues, minimum energy structures of several examples (e.g. Rh2(NHCOCH3)4, Rh2(NHCOCH3)4NC, Rh …


Functionalized Silica Gel For Adsorption Of Cesium From Solution, Kenneth Marshall Seaton Iii May 2017

Functionalized Silica Gel For Adsorption Of Cesium From Solution, Kenneth Marshall Seaton Iii

Electronic Theses and Dissertations

Mesoporous silica gel containing embedded phosphotungstic acid (PTA) was synthesized by sol-gel co-condensation of tetraethyl orthosilicate with PTA in acidic media. The obtained material had high Brunauer-Emmett-Teller Theory (BET) surface area and pore volume. A characteristic band of the Keggin structure of PTA was present in its FT-IR spectrum while its X-ray diffraction patterns were absent. This proved the embedding of PTA on a sub-molecular level and not as a second phase. Acidic sites were determined by neutralization with base in aprotic solvent, followed by titration of the remaining base with an acid. The material demonstrated high adsorption capacity of …


Role Of Nanoparticles In Voltammetric Signal Enhancement Exhibited By Layer-By-Layer (Lbl) Gold Nanoparticle-Modified Screen-Printed Carbon Electrodes (Spces), Ben K. Ahiadu May 2017

Role Of Nanoparticles In Voltammetric Signal Enhancement Exhibited By Layer-By-Layer (Lbl) Gold Nanoparticle-Modified Screen-Printed Carbon Electrodes (Spces), Ben K. Ahiadu

Electronic Theses and Dissertations

Screen-printed electrodes (SPEs) have found wide use as sensing platforms due to their simple fabrication, customizability in terms of geometry and composition, and relatively low cost of production. Nanoparticles have been incorporated in or interfaced with SPEs in order to improve sensor response or provide electrocatalytic capabilities. Though nanomaterial-modified SPEs are becoming increasingly common sensing platforms, the benefits provided by nanomaterials are often determined through voltammetric studies with common redox probes, such as ferricyanide. However, recent reports have documented the ferri-/ferrocyanide redox couple to be an unreliable system for characterizing some carbon-based electrodes due to the dependence of its electrochemical …


Homogeneous Ligand-Centered Hydrogen Evolution And Hydrogen Oxidation : Exploiting Redox Non-Innocence To Drive Catalysis., Andrew Z. Haddad May 2017

Homogeneous Ligand-Centered Hydrogen Evolution And Hydrogen Oxidation : Exploiting Redox Non-Innocence To Drive Catalysis., Andrew Z. Haddad

Electronic Theses and Dissertations

Hydrogen is a promising carbon-free fuel / energy carrier and is an essential building block for many industrial and agricultural processes. Rising energy demands have ignited interest in the development of carbon-free and carbon neutral energy sources. In this context, hydrogen is an attractive candidate—being energy-dense, carbon-free—and easily accessible through a two-electron reduction of water. Accordingly, many electrochemical homogeneous catalyst systems have been studied, with a focus on understanding the mechanism of hydrogen evolution proceeding through metal-hydride intermediates. However, there has been a renaissance in hydrogen evolution reaction (HER) catalyst design, with many groups implicating ligand redox non-innocence as a …


Development Of Recyclable Gold Nanoparticles For Routine Benchtop Catalysis In Organic Transformations., Shengzong Liang May 2017

Development Of Recyclable Gold Nanoparticles For Routine Benchtop Catalysis In Organic Transformations., Shengzong Liang

Electronic Theses and Dissertations

Homogeneous gold catalysis is a popular research area due to its high efficiency. Various gold catalysts have been utilized in organic synthesis and their reaction mechanisms are also well understood. However, most gold catalysis suffers from high catalyst loading or catalyst decay problems. In addition, homogeneous gold catalysts are not recyclable. These disadvantages have limited their application in large-scale synthesis and also caused a serious waste of this precious metal. A solution for these problems is to use a recyclable heterogeneous gold catalyst. So in this study, with the aim of making gold chemistry greener we successfully used heterogeneous gold …


Quantification Of Airborne Fungal Spores Comparing Molecular Tracers Via Ion Chromatography And Uv-Lif Methods, Marie Ila Gosselin Jan 2017

Quantification Of Airborne Fungal Spores Comparing Molecular Tracers Via Ion Chromatography And Uv-Lif Methods, Marie Ila Gosselin

Electronic Theses and Dissertations

Fungal spores represent an understudied subcategory of bioaerosols that can impact human health as pathogenic and allergenic particles. Fungal spores also have been shown to act as effective ice nuclei and giant cloud condensation nuclei in some cases. This has implications on the hydrological cycle on local and regional scales by impacting the formation and evolution of clouds and precipitation. The quantification of fungal spores has been limited in the past due to methods that were costly and that suffered from poor time resolution. The most commonly applied methods for airborne fungal spore analysis have traditionally included microscopy and culturing, …


Mechanistic Insights Into The Radical S-Adenosyl L-Methionine Enzyme Mftc, Bulat Khaliullin Jan 2017

Mechanistic Insights Into The Radical S-Adenosyl L-Methionine Enzyme Mftc, Bulat Khaliullin

Electronic Theses and Dissertations

Mycofactocin is a putative peptide-derived redox cofactor in Mycobacterium family. Its putative biosynthetic pathway is encoded by the operon mftABCDEF. The initial step of this pathway is a posttranslational modification of a peptide precursor MftA, which is catalyzed by MftC enzyme. This modification only occurs in the presence of chaperone MftB. Here, we demonstrate that MftC is a radical S-adenosyl L-methionine (SAM) enzyme and we examine its catalytic mechanism. We show that the modification of MftA requires two equivalents of SAM and is implemented in two steps: (i) the decarboxylation of a C-terminal tyrosine, resulting in formation of an …


Mechanochemical Synthesis Of Fuels From Sustainable Sources Utilizing Solid Catalysts, Jacob Todd Jan 2017

Mechanochemical Synthesis Of Fuels From Sustainable Sources Utilizing Solid Catalysts, Jacob Todd

Electronic Theses and Dissertations

Mechanochemistry requires less solvents which results in less waste generation. The question becomes can we apply mechanochemistry to current chemical reactions and reduce the generation of waste. This process can be simple or can be very extensive resulting in the generation of large amounts of waste and very little product. A significant advantage of mechanochemistry is the reduced need for solvents that would be common place for reactions. Mechanochemistry transfers energy to reagents via impacts from milling media. Energy can be transferred to the reagents no matter their state-of-matter. Much of the current studies in mechanochemistry today are done using …


Sequential Growth Of Molecular Complexity Via Alternating Ground State And Photochemical Reactions, Haibo Li Jan 2017

Sequential Growth Of Molecular Complexity Via Alternating Ground State And Photochemical Reactions, Haibo Li

Electronic Theses and Dissertations

A new strategy of increasing molecular complexity by post photochemical oxidation followed by secondary intramolecular photochemical reaction is developed. It is based on the mild oxidation of photochemical generated alcohol by primary intramolecular cycloaddition of aromatic o-aminoaldehydes and a secondary intramolecular cycloaddition of aromatic o-aminoketone. Both cycloadditions are triggered via excited-state intramolecular proton transfer (ESIPT). Additionally, an efficient continuous reaction of photocatalyzed 2-nitrobenzyl alcohol intramolecular reduction and aryl nitroso Diels-Alder (NDA) reaction was discovered.


Detection Of Inorganic Phosphate In Environmental Water Samples Using A Terbium And Gold Nanoparticle-Based Fret Chemosensor, Madeleine Johnson Jan 2017

Detection Of Inorganic Phosphate In Environmental Water Samples Using A Terbium And Gold Nanoparticle-Based Fret Chemosensor, Madeleine Johnson

Electronic Theses and Dissertations

A novel chemosensor for the detection of inorganic phosphate (Pi) in environmental water samples is outlined. The sensing solution is comprised of a luminescent lanthanide, terbium (Tb3+), chelated to ethylenediaminetetraacetic acid (EDTA) acid in solution with cetyltrimethylammonium bromide (CTAB)- capped gold nanoparticles (AuNPs). The Tb-EDTA and AuNPs undergo a Fluorescence resonance energy transfer (FRET) mechanism in which the Tb3+ luminescence is quenched. Upon the addition of inorganic phosphate (Pi), the AuNPs begin to aggregate and precipitate out of solution. The aggregation of AuNPs results in the restoration of the Tb-EDTA signal which can then be correlated to Pi concentration in …


Investigating The Atmospheric Production Of Perchlorate: Inference From Polar Ice Cores, Thomas S. Cox Jan 2017

Investigating The Atmospheric Production Of Perchlorate: Inference From Polar Ice Cores, Thomas S. Cox

Electronic Theses and Dissertations

Perchlorate (ClO4) in the environment is of concern, because of potential health risks to humans, among other reasons. Evidence suggests that the majority of environmental perchlorate is formed in the atmosphere (likely in the stratosphere), in chemical processes involving ozone and stratospheric chlorine. A lack of knowledge in regards to the processes has resulted in a limited understanding of the environmental conditions and variables that influence perchlorate production and consequently perchlorate prevalence and variability in the environment. In this study, perchlorate was measured, using an established ion chromatography-­‐electrospray ionization-­‐tandem mass spectrometry (IC-­‐ESI-­‐ MS/MS) technique, in over 1,600 snowpit …