Physical Sciences and Mathematics Commons^™

Investigations Into Ambient Ionization Mechanisms: Electrospray Ionization And Direct Analysis In Real Time Mass Spectrometry, Stephen Colin Gibson

Doctoral Dissertations

Mass spectrometry (MS) is an important tool for chemical analyses. Despite the MS requirement for generation of analyte gas-phase ions, many ion source designs afford little-to-no fragmentation, allowing characterization of intact molecules. However, this does not assure that detected ions are representative of the analytes’ natural state. Ionization mechanisms are generally complex and rarely fully understood. Fundamental research into these mechanisms provides greater insight into the relationship between solution chemistry and mass spectra. Work herein addresses aspects of two ambient ionization mechanisms: electrospray ionization (ESI) and Direct Analysis in Real Time (DART).

Ions produced by ESI are dispersed into a …

Simultaneous Determination Of Multiple Actinide Elements In A Variety Of Soils Utilizing A Standardized Sequential Extraction Protocol, Sherry Alina Faye

UNLV Theses, Dissertations, Professional Papers, and Capstones

To obtain a better understanding of the mobility of actinide element contaminants in the environment, the association of the contaminants with specific host phases of soils and sediments must be investigated. This investigation is most commonly conducted using sequential extraction techniques that employ the selective dissolution of soil phases with increasingly aggressive chemical treatment. Though several sequential extraction studies exist in literature, conclusions cannot be made by direct comparison of data due to the lack of uniformity in the protocols used. This work aims to continue development of a standard sequential extraction protocol and expanding its capabilities to include the …

Probing The Unfolding And The Stability Of The Last Four Metal Binding Domains Of Wilson Disease Protein Using Circular Dichroism And Novel Spectroscopic Techniques, Ibtesam Yaseen Alja’Afreh

Dissertations

Wilson disease protein is a copper-transporting P_1B type ATPase. It has large N-terminal copper binding domain which is composed of six homologous sub-domains. Each of these six domains is ~72 residues and connected to one another by linking regions of various lengths. They all possess similar ferrodoxin fold, and metal-binding motif, MXCXXC.

The need of having six metal binding domains and the manner in which they are communicating with each other is not well understood. To better understand how the last four metal binding domains function, I pursued a detailed biophysical characterization of these domains. Using molecular biology I …

Identification And The Significance Of Selective Proteins In Bile And Plasma Of Normal And Health-Compromised Chickens, Balamurugan Packialakshmi

Graduate Theses and Dissertations

During the last 50 years, animal breeding programs in commercial poultry have made significant progress in the bodyweight gain of broilers but led to several metabolic and skeletal disorders. Lameness associated with proximal femur known as femoral head separation (FHS) or femoral head necrosis (FHN) is one of the major metabolic disorders in poultry industry. In order to select for healthy chickens, markers that can distinguish between healthy and affected birds are required. Biomarkers from blood represent an ideal and rich source of markers which can be obtained using minimally invasive methods. The biomarkers were explored in an experimental model …

Diffusion And Adsorption Coefficients Of Aromatic Hydrocarbons In Gas Chromatography Capillary Columns, Gabriela Navarro Tovar

Electronic Thesis and Dissertation Repository

This study focuses on a mathematical description of aromatic species elution peaks from a gas chromatographic BPX5 capillary column. Using the chromatographic peaks, statistical moments are calculated for toluene, naphthalene, phenol and 2-naphthol. This thesis reports two modelling approaches involving laminar gas flow, distribution coefficients (K_s) and diffusion coefficients in the stationary phase (D_s).

Firstly, a model with equilibrium adsorption is considered to describe symmetric peaks for toluene and naphthalene. Moreover, a model with non-equilibrium adsorption is proposed to describe asymmetric peaks of phenol and 2-napthol. In addition to the K_s and D …

Mass Spectrometry Based Experimental Strategies To Characterize Native And Non-Native Disulfide Bonds In Cysteine-Rich Protein Therapeutics, Adriana Z. Kita

Doctoral Dissertations

The impact post-translational modifications (PTMs) can have on the structure, function, and immunogenicity of protein therapeutics makes it especially important for these protein-based treatments to be well characterized. Mass spectrometry has become instrumental in the examination of enzymatic and non-enzymatic PTMs. Disulfide bonds fall into both of these categories in which native disulfide bonds are formed in the ER by disulfide mediated enzymes and non-native disulfide bonds are often formed by non-enzymatic reducing/oxidizing reactions. Disulfide bonds are particularly important for protein folding and reinforcing higher order structure, and are typically characterized by LC-MS of non-reduced peptides. However, characterizing the disulfide …

Volatile Profiles And Resistance To Herbivory In Eastern Hemlock, Elizabeth A. Mckenzie

Masters Theses

Eastern hemlock hosts the hemlock woolly adelgid, an introduced sap-feeding insect that causes rapid deterioration of the host. Like most conifers, eastern hemlock produces a variety of constitutive and induced defenses, primarily terpenoids. To explore the relationship of terpenoid defenses with adelgid infestations, we artificially infested hemlocks at a forest site and a plantation site, and compared their terpenoid concentrations to those in control trees. Infested trees showed lower terpenoid concentrations than control trees, suggesting that eastern hemlock not only fails to induce production of terpenoids in response to adelgid infestation, but becomes less able to produce carbon-based defenses due …

Modification Of Gold Nanoparticles For Sers Application In Emulsion And Lipid Systems, Michael J. Driver

Masters Theses

Gold nanoparticles produced using the Turkevich method were able to have their hydrophobicity modified using octanethiol in a novel method for SERS application. Both amphiliphic GNPs and hydrophobic GNPs were produced and differentiated by Raman signals. The amphiliphic GNPs were able to enhance the SERS signals of the protein emulsifier in the emulsion in situ and the hydrophobic GNPs were able to enhance the SERS signals from canola oil. Further purification of the hydrophobic GNPs proved to have higher enhancement and sensitivity, but still poor consistency which is typical of SERS. Monitoring lipid oxidation using Raman and SERS using alternative …

Aircraft-Based Measurements For The Identification And Quantification Of Sources And Sinks In The Carbon Cycle, Dana R Caulton

Open Access Dissertations

Improved quantification of carbon-cycle sources and sinks is an important requirement for determining mitigation strategies and modeling future climate interactions. Analytically robust measurements require high-precision instrumentation and thoughtful experimental design to produce rigorous and reproducible results despite complex and quickly changing meteorological and environmental conditions. Here, an aircraft platform equipped with a high-precision cavity ring-down spectrometer for CO₂, CH₄ and H₂O quantification was used to acquire data from previously un-sampled sources. The aircraft mass-balance technique was used to quantify CH4 emissions from natural gas well pads in the drilling stage, which were 2-3 orders of …

New Strategies To Reveal Protein Candidates In Protein-Protein Interactome Study, Meng-Chieh Chen

Open Access Theses

Comprehensive protein-protein interaction network analysis can help reveal protein functions in a system-wide manner. A reliable knowledgebase of interaction networks is not only important for selecting the candidates for drug therapies, but also for evaluating the disease risk. In current interaction databases, 322579 interactions comprised of 56460 proteins have been reported (statistical analysis from APID: Agile Protein Interaction DataAnalyzer; http://bioinfow.dep.usal.es/apid/index.htm). The huge datasets are contributed mainly by yeast -two -hybrid (Y2H) screening and affinity-purification followed by mass spectrometry (AP-MS). High false positive rates and failing to cover certain interaction categories are the limitations of these two methods. Here, we developed …

Analysis Of Tyrosine And Its Halogenated Forms And Tripeptide –Metal Ion Clusters Using Mass Spectrometry, Bharathi Gannamani

All Capstone Projects

Chapter 1:

The aim of this research project was to measure the differences in proton affinities of tyrosine and its halogenated forms, 3-chlorotyrosine and 3-iodotyrosine. Tandem mass spectrometry was used here to measure the proton affinities. These amino acids were formed as protonated dimers with amino acids of known proton affinity and were introduced into the instrument through electrospray ionization (ESI). Based on the intensities of the protonated amino acids appeared in the mass spectrum when the dimer was isolated and fragmented, the proton affinities of the sample amino acids were calculated.

Chapter 2:

The research project was on mass …

Green Chemistry, Mary Lynn Koster

All Capstone Projects

In the academic year of 2014-2015, Governors State University will be accepting and enrolling freshman into the university. Therefore, the chemistry department will be offering general chemistry for the first time in its history. Now is the time to introduce the concept of Green Chemistry. Green Chemistry is not a new class but a philosophy that the department or at least the individual experiments within a lab course needs to looks at. There are 12 Principles of Green Chemistry:

1. Prevention
2. Atom Economy
3. Less Hazardous Chemical Syntheses
4. Designing Safer Chemicals
5. Safer Solvents and Auxiliaries
6. Design for Energy Efficiency
7. Use of Renewable …

Reverse-Phase Liquid Chromatography Of Small Molecules Using Silica Colloidal Crystals, Natalya Khanina

Open Access Theses

Capillaries packed with a silica colloidal crystal (SCC) of 470 nm nonporous particles have recently been shown to offer significant improvements in the peak width, resolution, and speed of protein analysis due to the reduction of the A and C term broadening contributions of the Van Deemter equation. While protein separations using this technology have shown vast improvements, small molecules remain largely unexplored. As the SCC allows for an approximately diffusion limited system, extremely high plate numbers are expected for small molecule separations. The research presented herein studies the feasibility of pressure-driven small molecule separation using SCCs and commercial instrumentation. …

The Kinetic Method: Determination Of Proton Affinity Of Proline By Cis And Trans Hydroxylation, Vinod Kanchi

All Capstone Projects

Unknown Proton affinity (PA) of the amino acids were determined by comparing them with known PA of the reference standards. Initially we mixed 2 amino acids together [unknown (PA) and known (PA)] and introduce into mass spectrometer using direct infusion. After injecting we observe the peaks. The protonated dimer peak of known PA and unknown PA samples were isolated and fragmented. Once they were fragmented protonated dimer will produce two peaks corresponding to amino acid with unknown PA and amino acids with known PA. Based on the ratio of these amino acids we determine the unknown PA of an amino …

Resonant Two-Photon Ionization Studies Of Non Covalent Interactions In Halo Aromatic Clusters And Spin-Orbit Coupling Modeling In Mono-Halocarbenes, Silver Nyambo

Dissertations (1934 -)

Non-covalent interactions in halobenzenes (PhX) (X=F, Cl, Br) and phenylamine (C₆ H₅ NH₂ ) have been studied here using resonance two-photon ionization (R2PI) spectroscopy combined with a linear TOF-mass spectrometer. Their interaction with polar molecules in form of ammonia (NH ₃ ) and trifluorohalomethanes (CF₃ X) has also been studied. DFT and TD-DFT calculations using M06-2X functionals were carried out on different cluster conformations to compliment experimental results. A general trend of broadness in homogenous dimers (PhX)₂ , has been attributed to mainly the presence of multiple cluster isomers and Frank-Condon activity in the low …

Folate Targeted Agents For Diagnostic And Therapeutic Uses, Mekeda Carr

All Capstone Projects

Folic acid has been frequently exploited for target therapies geared toward overexpressed folate receptors on malignant cells. The folic acid/folate-receptor high affinity interaction can be used to not only target but image cancer cells. Folate-linked nanoparticles represent a potential new drug carrier for tumor cell-selective therapeutics. Folate targeting, nanoparticles in therapeutics, and cancer cell imaging will be outlined in this literature report.

Effect Of Gamma Radiation On The Interfacial Reactions And Transfer Processes Of Phosphonium-Based Ionic Liquids With Carbon Steel, Ryan P. Morco

Electronic Thesis and Dissertation Repository

This thesis presents work on the effects of ionizing radiation on phosphonium-based ionic liquids (ILs). Ionic liquids are known for their tunable properties which make them attractive options for applications for the separation and sequestration of metal ions from spent nuclear fuels, and candidate lubricants for systems under severe conditions. The high radiation environment found in spent fuel processing may decompose the solvents (ILs) used in the process and affect their separation efficiency. The radiolytic decomposition products can also alter the physical and chemical properties of an IL in ways which can affect the potential corrosion of metal alloys in …

Mass Spectrometric Characterization And Imaging Of Nanoparticles In Biological Samples, Bo Yan

Doctoral Dissertations

Nanoparticles (NPs) are being investigated widely for use in biomedical applications such as imaging, drug delivery, and cancer therapy due to their small size and readily tunable properties. The ability to accurately characterize NPs and monitor their spatial distributions is highly desirable for effective use of NPs and evaluation of their potential adverse environmental, health, and safety effects. In this dissertation, a simple, fast, and sensitive method based on laser desorption/ionization mass spectrometry (LDI-MS) to characterize and track NPs in biological systems has been developed. This method is especially well suited for characterizing core-shell structured NPs, such as quantum dots …

Protein Behavior Directed By Heparin Charge And Chain Length, Burcu Baykal Minsky

Doctoral Dissertations

Glycosaminoglycans (GAGs), highly charged biological polyelectrolytes, are of growing importance as biomaterials and pharmaceutical drugs due to their immense range of physiological functions. They bind to many proteins; however, the degree of structural selectivity in GAG-protein interactions is largely unknown .Our studies have focused on the importance of heparin (a model GAG) charge and chain length in protein binding in order to explore its potential applications in biofunctional tissue scaffold materials, as polysaccharide drugs in anticoagulation, and as inhibitory agents in protein aggregation. We used electrospray ionization mass spectrometry, capillary electrophoresis, size exclusion chromatography, dynamic/static light scattering and electrostatic protein …

Cell-Based Sensing Of Endocrine Disrupting Substances Using Fluorescent Protein-Gold Nanoparticle Complexes, Xian Wang

Masters Theses

Developing a sensitive and effective in vitro bioassay to detect endocrine disrupting chemicals (EDCs) would reduce the cost, eliminate the possibility of low dose effects, detect the non-monotonic dose responses, and identify mechanisms of actions. The “chemical nose” sensing method using supramolecular complexes composed of cationic monolayer functionalized gold nanoparticles (AuNPs) and fluorescent proteins (FPs) can successfully distinguish serum proteins, mammalian cells, tissue lysates, and chemotherapeutic drug mechanisms. EDCs regulate target cells via genomic or non-genomic pathways in terms of proliferative effect and response time. In this thesis, green fluorescent protein-gold nanoparticle (GFP-AuNP) sensors were used to detect the proliferative …

Optimization Of P-Type Czts Nanocrystal Thin Film Layers For Applications In Low Cost Photovoltaic Devices, Kyle S.B. Jeffs

Electronic Thesis and Dissertation Repository

In this thesis Cu2ZnSnS4 nanocrystal synthesis was optimized by way of photoelectrochemical measurements through tuning the stoichiometry. Formation of a Cu2ZnSnS4 light-absorbing layer was studied using multiple depositions methods. These included dropcasting, electrophoretic deposition, and use of 3-mercaptopropyl trimethoxysilane as a chemical linker. Dropcasting samples were compared according to the solvents used to suspend the nanocrystals. Photoelectrochemical measurements were used to compare dropcasting with electrophoretic deposition and use of 3-mercaptopropyl trimethoxysilane as a chemical linker. Dropcasting was shown to be the least effective method of depositing the light-absorbing layer. Samples prepared by electrophoretic deposition were optimized according to a number …

Electrogenerated Chemiluminescence Of Gold Nanoclusters, Mahdi Hesari

Electronic Thesis and Dissertation Repository

A series of monodispersed AuNCs including Au144(SR)60, Au38(SR)24 and Au25(SR)18z (z =1-, 0 and 1+, SR=2-phenylethanethiol) were prepared. All these nanoclusters showed molecule-like optical and electrochemical properties. These two features are essential for an electrogenerated chemiluminescence or electrochemiluminescence (ECL) study. The Au144(SR)60 showed a small HOMO-LUMO gap determined by electrochemistry. No ECL light was seen in the annihilation process, while NIR ECL was observed with tri-n- propylamine (TPrA) (Chapter 2). ECL was highly efficient in the Au38(SR)24/TPrA co- reactant system. This nanocluster also showed ECL emission with benzoyl peroxide (BPO), while no ECL was detected in the annihilation route (Chapter …

Mechanisms And Transients Involved In The Solar Conversion Of Petroleum Films In Aquatic Systems, Phoebe Z. Ray

University of New Orleans Theses and Dissertations

The behavior of Deepwater Horizon crude oil and other sources of oil were investigated when exposed to sunlight in aquatic systems under environmentally relevant conditions. This research decoupled the abiotic and biotic weathering modifications of oil by focusing solely on the photochemical transformations of oil in aquatic systems. Photochemical rates and mechanisms were measured through the determination of reactive transients. Total hydroxyl radical formation was studied using high benzoic acid concentrations and varying exposure time. Titanium dioxide (TiO₂) nanomaterials were added to the system in an effort to determine if the photocatalyst would enhance oil photodegradation. Photochemical production …

Determining Kinetics For Simulated Sunlight-Exposed Oil Compounds, Dustin D. Kountz

University of New Orleans Theses and Dissertations

Understanding of the fate of oil in the environment is of utmost importance; however, accurate, predictive models are still in very early stages. To aid in the development of these models, photodegradation of selected polycyclic aromatic hydrocarbons (PAHs) in an n-alkane hydrocarbon matrix was followed for individual PAHs and mixtures of PAHs similar to that found in the Deepwater Horizon spill. Tetracene in tetradecane photodegraded quickest of all observed PAHs, with a loss of 99% after only one hour of irradiation. Binary mixtures of PAHs showed different degradation amounts, including changes in PAH kinetics. These results suggest that the …

Synthesis And Applications Of Mutimodal Hybrid Albumin Nanoparticles For Chemotherapeutic Drug Delivery And Phototherml Therapy Platforms, Donna V. Peralta

University of New Orleans Theses and Dissertations

Progress has been made in using human serum albumin nanoparticles (HSAPs) as carrier systems for targeted treatment of cancer. Human serum albumin (HSA), the most abundant human blood protein, can form HSAPs via a desolvation and crosslinking method, with the size of the HSAPs having crucial importance for drug loading and in vivo performance. Gold nanoparticles have also gained medicinal attention due to their ability to absorb near-infrared (NIR) light. These relatively non-toxic particles offer combinational therapy via imaging and photothermal therapy (PPTT) capabilities.

A desolvation and crosslinking approach was employed to encapsulate gold nanoparticles (AuNPs), hollow gold nanoshells (AuNSs), …

Extending The Limits Of Solid Phase Microextraction, Shilpi Chopra

Seton Hall University Dissertations and Theses (ETDs)

Solid phase microextraction (SPME) is a solventless extraction technique that combines sample preparation and sample introduction into a gas chromatograph into a single step. For the past 20 years, solid-phase micro-extraction (SPME) has been used in numerous fields such as: food analysis, including juices, alcohols fruits and vegetables for volatiles, aroma, caffeine, fatty esters, environmental applications including volatile organic contaminants, polycyclic aromatic hydrocarbons, polychlorinated biphenyls, phenols, pesticides, steroids, herbicides, acid/neutral/base compounds, and organometallic compounds from water, air, soil, sludge, and sediment samples and in biomedical analysis.

This work demonstrates the extension of the limitations of SPME with respect to extraction …

The Implications Of Content Analysis For The Interpretation Of Unguentaria In Museum Collections, Jenna L. Mortensen

Theses and Dissertations

Scent has traditionally been an ephemeral component of rituals in ancient societies, including burial and other practices associated with the anointing of the body (Classen et al. 1994: 43; Houston and Taube 2000: 271). This thesis investigates the possible signifiers and social impact such scents might have had for individuals participating in such rituals by using the little explored approach of sensory archaeology. A discussion of the correlation between olfaction and the triggering of both the experiential and emotional aspects of memory contributes to a broader view of these rituals in the anthropological literature (Classen et al. 1994), while Houston …

Modified-Electrodes For Redox-Magnetohydrodynamic (Mhd) Pumping For Microfluidic Applications, Christena Kayl Nash

Graduate Theses and Dissertations

A new microfluidic pumping and stirring technique was demonstrated for lab-on-a-chip applications. Microfluidics was accomplished via redox-MHD, which takes advantage of a body force (F_B) that is generated when there is a net movement of ions in solution (j) in the presence of a perpendicular magnetic field (B), according to the equation F_B = j×B. In this work the movement of ions in solution was generated using electrodes modified with the conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT) rather than a redox species in solution, which can interfere with analyte detection and with biological species. …

Structural Studies Of Bile Salt Aggregation By Nuclear Magnetic Resonance Spectroscopy And Mass Spectrometry, Nicholas Doyle

Master’s Theses

Bile salts are biomolecules that are produced in the liver and are responsible for a range of functions in the process of digestion, primarily the emulsification of dietary fat and fat-soluble vitamins. Despite their importance in biological chemistry, the structure and dynamics of bile salt aggregation are not well understood. The efforts described herein attempt to enhance the understanding of cholate aggregation numbers (AN), critical micelle concentration (CMC), micellar structure(s), and interactions with a binaphthyl probe molecule. Cholate is the most common bile salt in mammals and is, therefore, a decent model for describing bile salt aggregation. CMC determination is …

The Influence Of Microstructure On The Corrosion Of Magnesium Alloys, Robert M. Asmussen

Electronic Thesis and Dissertation Repository

This thesis reports a series of investigations into the influence of microstructure on the corrosion of Mg alloys. Mg alloys are prime candidates for the light-weighting of automobiles however any extensive applications are limited by their high corrosion rates. The corrosion resistance is further hindered by the susceptibility of Mg alloys to microgalvanic coupling occurring between the Mg matrix and the secondary microstructures in the alloys. This process and the individual contributions to it must be understood to improve Mg alloy design for automotive applications, develop methods for extending the lifetime of Mg alloys and developing models to successfully predict …