Chemistry Commons^™

In-Column Polymer Modifications: Advancing Polymer Bonded Phases, Alexis G. Huckabee

Open Access Dissertations

Glycosylation is the most common post-translational modification affecting protein activities, including delivery to cell surface, binding affinity, and mediating different physiological effects. Separations of glycoproteins and their glycoforms are essential for drug discovery and development, identification of potential disease biomarkers and quality control. The efficiency of glycoprotein separations is limited by the bonded phases, requiring advances in chromatographic materials. Such advances would improve resolution, allowing for more species to be isolated from a mixture and studied.

Our group found that submicrometer nonporous silica stationary phases with tethered polymer chains (acrylamide) give excellent hydrophilic liquid chromatography (HILIC), a common method used …

Ambient Ionization - Mass Spectrometry: Advances Toward Intrasurgical Cancer Detection, Alan Keith Jarmusch

Open Access Dissertations

My dissertation research has focused on the development of ambient ionization – mass spectrometry (MS) for clinical measurements, specifically intrasurgical cancer detection. The molecular differences between normal and cancerous tissue were detected via direct tissue analysis in vitro by touch spray ionization (TS) or by analyzing sectioned or smeared tissue using desorption electrospray ionization (DESI). The physical form of the tissue, e.g. in vitro sampling, sectioned, or smeared, was inconsequential in differentiating normal from cancerous tissue; however, the spectra acquired by TS and DESI differed due to differences in ionization processes. We envision that TS-MS and DESI-MS could impact diagnostic …

Preparative Mass Spectrometry Applications In Nanomaterials And Organic Synthesis, Michael Wleklinski

Open Access Dissertations

Preparative mass spectrometry was traditionally a vacuum based experiment where mass selected ion beams were deposited onto surfaces; however, recently ions have been manipulated in the open air to perform accelerated synthesis. The work of this dissertation focuses on the generation of charged ions from microdroplets and their use in organic synthesis and the preparation of atomically precise metal nanoclusters. First the mechanism for charging in the zero volt paper spray will be presented. This works builds a computational model based on the statistical fluctuation of positive and negative charges based on the theory of Dodd. It is found through …

Electrogenerated Chemiluminescence Study Of Semiconductor Nanoparticles Towards Sensitive Detection Of Biomolecules, Yiliyasi Wusimanjiang

Dissertations

The main focus of this dissertation is to unfold the fundamental aspects of electrogenerated chemiluminescence (ECL) generation from semiconductor nanoparticles (also known as quantum dots or QDs) within different ECL systems. The ECL and photo-physical interactions between the CdTe QDs (λ_emission= ~760 nm) and the CdSe QDs (λ_emission= ~550 nm), as well as the effects of carbon nanotubes on ECL of QDs were separately investigated. Optimum experimental conditions for peptide bond formation on an electrode surface through EDC (1-ethyl-3-(-3-dimethylaminopropyl) carbodiimide hydrochloride)/NHS (N-Hydroxysulfosuccinimide) coupling were also revealed using cyclic voltammetry technique. Based on the information …

Direct Attachment Of 4-Hydroxybenzoic Acid Polymers And Capture Agents To Flat Sheet And Microdialysis Membranes For Improved Mass Transport, Sarah Jane Phillips

Graduate Theses and Dissertations

Microdialysis (MD) sampling is a diffusion-based separation method which has the ability to sample any analyte that can diffuse across the semi-permeable membrane. However one challenge for MD is that for soluble proteins greater than 10 kDa, the relative recovery (RR) using a 100 kDa MD probe is between 1-5%.1 There are two major barriers that lead to these low recovery values - nonspecific adsorption (NSA) and poor solute mass transport. To overcome these two barriers, the modification of PES-based MD membranes has been initiated by laccase. Previous researchers have used laccase to modify PES flat sheet and hollow fiber …

Interference Effects Of Urban Rubble On The Radioanalytical Analysis Of Strontium, Derek Roger Mclain

UNLV Theses, Dissertations, Professional Papers, and Capstones

Most current radioanalytical protocols have been developed for the analysis of air, water, soil and bioassay samples. While these protocols build the foundation of operational environmental monitoring, they are not necessarily suitable for the analysis of samples that will be encountered in the aftermath of a nuclear incident. In such a situation, it will be important to characterize the isotopes of interest present in the affected area to obtain signatures for nuclear forensics and ensure the appropriate response. Specifically, this research is aimed at the determination of strontium-90 and its separation from zirconium-90 in a post-detonation situation.

Strontium-90’s relatively long …

Fluorescent Graphene For Cancer Cell Targeting And Detection, Rabab Nadeem Hamzah

Theses and Dissertations

The highest cause of death and illness around the world is cancer, and the range of cancers continues to increase. Breast cancer is the second leading cause of cancer death in women today, mainly in older women (over 40 years), younger women can also be affected, especially those with a genetic predisposition. Early detection of breast cancer is needed in order to limit the risk of this disease and make significant improvements in the rate of cure. Combining clinical trials with bionanotechnology for the diagnosis and treatment of cancer has received considerable attention in the last several years. Different nanomaterials …

Graphene Quantum Dots Electrochemistry And Development Of Sensitive Electrochemical Biosensor [Hybrid Poster 1-B], Tyler Smith, Alexander Banaszak

Posters-at-the-Capitol

Graphene quantum dots (GQDs) are zero-dimensional material derived from graphene derivatives with characteristics from the structure of graphene with quantum confinement and edge effects possessing unique properties. Intense research activity in GQDs is attributed to their novel physical-chemical phenomena arising from the sp²-bonded carbon core surrounded with edge functional moieties. In this work, GQDs of optimal 5-7 nm size are investigated for their fundamental electrochemical properties and use in electrochemical sensing including enzyme-based glucose biosensor. Glucose oxidase (GO_x) was immobilized on GQDs modified glassy carbon (GC) and the UV-Vis absorption and fluorescence spectroscopy, electron microscopy, cyclic …

Hydrolytic And Nonhydrolytic Sol-Gel Zirconia-, Titania-, And Niobia-Based Capillary Microextraction Coatings For The Preconcentration And Hplc Analysis Of Catecholamine Neurotransmitters And Phosphorylated Peptides, Abdullah Awadh Alhendal

USF Tampa Graduate Theses and Dissertations

Sample preparation is the most error-prone step in chemical analysis. A great deal of efforts has been made to develop efficient techniques and protocols for sample preparation to accomplish important goals such as miniaturization and implementation of green analytical methodologies. Solid-phase microextraction (SPME) has successfully eliminated the use of hazardous organic solvents in extraction sampling, sample preparation, preconcentration and sample introduction to the analytical instrument in an effective manner. Ensuring thermal- and solvent-instability of traditional SPME extraction phases represented one of their main drawbacks. This was solved by the introduction of sol-gel SPME phases characterized by enhanced thermal-, solvent-, and …

P-26 Detection Of Counterfeit Antimalarial Drugs By Sers, Getahun Merga, P. Shepard, M. Trujillo, J. Camden

Celebration of Research and Creative Scholarship

Substandard antimalarial drugs are a major problem to the health of citizens in developing countries, and it is likely that the problem persists due to the lack of means to detect substandard drugs. Various colorimetric techniques have been implemented to determine if a drug contains the stated active ingredient or not, but vibrational spectroscopies such as NIR and Raman can be used to more reliably quantify the amount of active ingredient. The use of Raman, however, has been limited by the presence of significant sample fluorescence that interferes with detection of the SERS signals of the active ingredients. Thus, we …

The Study Of Dynamical Electrochemical Impedance Spectroscopy For Oxygen Reduction Reaction On Pt/C Catalyst, Kun-Ming Shi, Jian-Wei Guo, Jia Wang

Journal of Electrochemistry

With joint techniques of rotating disc electrode(RDE) and electrochemical impedance spectroscopy(EIS), and further establishment on equivalent circuit model, this paper studied oxygen reduction reaction(ORR) on commercial Pt/C catalyst in acid medium. Our results found that the dynamical interface on Pt/C consists of two independent processes: 1) the PtO reduction from Pt surface, 2) the new PtO formation from ORR, thus providing key clues for catalyst stability and activity. This also implied that the dynamical interface facilitates reconstruction for porous electrode, and matches with mass transfer. One important issue is discovered that at high overpotential, the high reaction rate for ORR …

The Investigation Of The Electrical Control Of Hemimicelles And Admicelles On Gold For Analyte Preconcentration, Dheyaa Hussein Al-Karawi

Masters Theses & Specialist Projects

Hemimicelles and admicelles are well-investigated wonders in modern science; they are surfactant monolayers and surface adsorbed micelles, respectively. Capacitance measurements for monitoring the formation of dodecyl sulfate (DS) surfactant monolayer on positively charged gold substrates (planar gold) and the adsorbance of 2-naphthol onto DS surfactant monolayer were performed. The investigation of the electrical control of DS at various concentrations (4, 6, 16, and 32 mM) below and above the critical micelle concentration (CMC= 8 mM) on gold surfaces for analyte preconcentration, prior to chromatographic analysis, is presented. Charged ionic surfactants, such as DS, drawn to a surface of opposite charge …

Quantitative Analysis Of Acetylsalicylic Acid By Q-Nmr (Quantitative-Nuclear Magnetic Resonance Spectroscopy), Charles Flemming Jr.

All Student Theses and Dissertations

Quantitative analysis is an important step during pharmaceutical drug development. Currently, the pharmaceutical industry uses high performance liquid chromatography (HPLC) for quantitative analysis of organic compounds as the preferred technique. The proton nuclear magnetic resonance (NMR) technique has an inherent ability to quantify a given analyte and may be used to quantify organic compounds. Quantitative nuclear magnetic resonance spectroscopy (q-NMR) of acetylsalicylic acid (ASA) was conducted using tert-butyl alcohol (tert-butanol) as the internal standard and deuterated chloroform (CDCl₃) as the solvent. Preparations of ASA solutions in low and high concentration ranges, 1.0 mM – 10.1 …

Electrochemical Nanoprobes For Electron Transfer Kinetics And Electrocatalysis Study, Yun Yu

Dissertations, Theses, and Capstone Projects

The studies of electrochemical processes on the nanoscale have led to a significant progress in understanding of electrochemical mechanisms and characterization of nanomaterials in the fields of energy, catalysis, and biological research. Electrochemical experiments at nanoscale require the fabrication and characterization of nanometer-sized electrochemical probes. The main advantages of the nanoprobes include very fast mass-transfer rate, high signal-to-noise ratio and extremely fine spatial resolution of electrochemical imaging. In the course of my Ph.D. research, different types of electrochemical probes were developed for measuring electron-transfer kinetics, probing single catalytic nanoparticles and sampling ultra-small volume of liquids.

We developed methodologies to fabricate …

Specific Binding Affinity Of The Non-Catalytic Domain Of Eukaryotic Like Type Ib Topoisomerase Of Vaccinia Virus, Benjamin R. Reed

Dissertations, Theses, and Capstone Projects

Topoisomerases are ubiquitous proteins that alter supercoiling in double stranded DNA (dsDNA) during transcription and replication and. vaccinia and the closely related poxvirus variola virus, at 314 amino acids in length, encode the smallest of the type I topoisomerases(TopIB). TopIB is a two domain protein that recognizes the sequence 5’-T/CCCTT, cleaves at the 3’-end and relaxes supercoiling through rotation. The C-terminal domain (CTD) alone contains the catalytic activity and specificity. Deletion of the N-terminal domain results in a greatly reduced rate of relaxation and rapid dissociation. Biochemical data suggests that the N-terminal domain (NTD) is important for pre-cleavage binding and …

Metabolic Profiling Of Genetically Modified Potato Periderm Tissues, Liqing Jin

Dissertations, Theses, and Capstone Projects

Potato tubers are protected from dehydration and pathogens by a covering peel (periderm) impregnated with suberin, a complex cross-linked biopolymer that contains both polyaliphatic and lignin-like aromatic domains. Current models describing the macromolecular structure of suberin assume that ferulic acid cross-links both domains as it may form carboxyl ester bonds with aliphatic monomers and non-ester radical-coupled bonds with phenolics. Ferulic acid also links by ester bonds to glycans and acts in cross-linking polysaccharides and lignin. Fatty alcohol/ω-hydroxyacid hydroxycinnamoyl transferase (FHT) is a BADH acyltransferase responsible for the synthesis of akyl-ferulates that is necessary for suberin biosynthesis. Periderm from FHT-RNAi …

Metabolic Profiling And Polymer Formation Of Gene Silenced Potato Periderms, Qing Cai

Dissertations, Theses, and Capstone Projects

Suberin is a biopolyester constituent of specialized plant periderm tissues formed within the phellem cell walls. Suberin and waxes of the periderm layer act to prevent water diffusion, mechanical breakdown and pathogenic invasion in plants. Ferulic esters, ω-hydroxyacids and α,ω-fatty diacids are considered to be the most important linkage between aliphatic and aromatic suberin domains and also linked with cell-wall polysaccharides. The potato gene FHT (fatty ω- hydroxyacid/fatty alcohol hydroxycinnamoyl transferase) esterifies ferulic acid to suberin. Diminished levels of feruloyl transferase activity have been associated with lowered amounts of feruloyl esters of fatty acids in both suberin-associated waxes and suberin …

A Complex Legacy Of Contamination In Urban Estuarine Systems, Michael A. Kruge

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

Industrialized urban waterways have typically suffered decades of contamination, varying in source and intensity as manufacturing and transportation practices evolved. The U.S. Environmental Protection Agency designates locales with particularly severe contamination as Superfund sites. Among these, the Gowanus Canal and lower Passaic River in the New York/New Jersey harbor estuary illustrate a complex range of contamination types.

The 2.2 km Gowanus Canal, with sluggish circulation driven mostly by tides, accumulated fine-grained sediments (average thickness of 3 m) highly enriched in organic carbon (OC, mean 11 % but up to 49 %) derived from hydrocarbons, sewage, coal, char, and biomass, along …

First-Principles Calculated Decomposition Pathways For Libh4 Nanoclusters, Zhi-Quan Huang, Wei-Chih Chen, Feng-Chuan Chuang, Eric Majzoub, Vidvuds Ozoliņš

Physics Faculty Works

We analyze thermodynamic stability and decomposition pathways of LiBH4 nanoclusters using grand-canonical free-energy minimization based on total energies and vibrational frequencies obtained from density-functional theory (DFT) calculations. We consider (LiBH4)n nanoclusters with n = 2 to 12 as reactants, while the possible products include (Li)n, (B)n, (LiB)n, (LiH)n, and Li2BnHn; off-stoichiometric LinBnHm (m ≤ 4n) clusters were considered for n = 2, 3, and 6. Cluster ground-state configurations have been predicted using prototype electrostatic ground-state (PEGS) and genetic algorithm (GA) based structural optimizations. Free-energy calculations show hydrogen release pathways markedly differ from those in bulk LiBH4. While experiments have found …

A Comparison Of Solvent And Water-Borne Alkyd Coatings And The History Of Voc Regulations In The United States, Molly Elise Burns

Master's Theses

A Comparison of Solvent and Water-Borne Alkyd Coatings Abstract

Conventional solvent based alkyd coatings have gone out of favor due to concerns over volatile organic compound (VOC) content. However, due to recent focus on renewable raw materials, alkyds are making a comeback in waterborne form. Water based alkyd coatings are known to have poor shelf stability and corrosion resistance, as well as other problems during the formulation process. This project focused on comparing solvent borne to two types of water-borne alkyds, water reducible alkyds and alkyds emulsions. The purpose was to understand the differences between the three types of alkyds …

Using In Situ Liquid Single Photon Ionization Mass Spectrometry (Spi-Ms) To Probe Lithium Polysulfide Electrolyte In Motion, Aala M. Al Hasan, Jiachao Yu, Juan Yao, Vijayakumar Murugesan, Manjula Nandasiri, Xiao-Ying Yu

STAR Program Research Presentations

The solid-liquid (s-l) interface is the most common interface encountered in electrochemical systems. The s-l interface has wide applications in energy storage, catalysis, and material sciences. In situ studies of chemical reactions taking place on the s-l interfaces can further our understanding of electron transfer and link to real-world device functions under challenging conditions. Direct probing of the solid electrode and liquid electrolyte interface has been realized using a vacuum compatible electrochemical microfluidic reactor, system for analysis at the liquid vacuum interface (SALVI) with time-of-flight secondary ion mass spectrometry (ToF-SIMS). Most recently, the electrochemical version of SALVI was integrated to …

Determination Of Dimethyl Trisulfide In Rabbit Blood Using Stir Bar Sorptive Extraction Gas Chromatography-Mass Spectrometry, Erica Mananadhar, Nujud Maslamani, Ilona Petrikovics, Gary A. Rockwood, Brian A. Logue

Chemistry and Biochemistry Faculty Publications

Cyanide poisoning by accidental or intentional exposure poses a severe health risk. The current Food and Drug Administration approved antidotes for cyanide poisoning can be effective, but each suffers from specific major limitations concerning large effective dosage, delayed onset of action, or dependence on enzymes generally confined to specific organs. Dimethyl trisulfide (DMTS), a sulfur donor that detoxifies cyanide by converting it into thiocyanate (a relatively nontoxic cyanide metabolite), is a promising next generation cyanide antidote. Although a validated analytical method to analyze DMTS from any matrix is not currently available, one will be vital for the approval of DMTS …

The Use Of Stable Isotopes And Particulate Matter In The Investigation Of Local And Regional Atmospheric Chemistry, Tanya Lynn Katzman

Open Access Dissertations

The chemical composition of particulate matter (PM), a known contributor to air pollution, is highly variable, and elemental analysis reveals information about local and regional sources, as well as how air masses and climate influence PM compositions. Seasonal changes in climate, such as temperature, amount of daylight, or meteorological patterns influence source emissions (increased residential heating activities, decreased natural soil emissions) and the relative importance of certain chemical pathways in the atmosphere. Since the magnitude of these seasonal changes are highly dependent on location, each sampling site is unique and the chemical composition of PM provides valuable insight into local …

Comparative Analysis Of In Situ Fibronectin Using Tof-Sims, Spi-Ms, And Dropdesi-Ms In A Microfluidic Reactor, Shannon Fasing, Xiao-Ying Yu, Juan Yao, Jiachao Yu

STAR Program Research Presentations

Fibronectin is an important biomolecule due to its role in cell differentiation, growth, kinesis, and adhesion. Such biological responses are mediated through membrane recognition and signaling; where fibronectin is found. Studying the outer molecular surface of fibronectin allows deeper insight into the microbiological reactions that occur during these processes. In situ mass spectrometry analysis in aqueous solution accurately represents fibronectin’s chemical components, made possible by a vacuum compatible microfluidic reactor, SALVI (System for Analysis at the Liquid Vacuum Interface). SALVI was paired with the analytical tools: time-of-flight secondary ion mass spectrometer (ToF-SIMS), single photon ionization mass spectrometer (SPI-MS) and drop …

Polymerizable Lipids For Controlled Functionalization Of Layered Materials, Kortney Kaye Rupp

Open Access Theses

Self-assembled monolayers (SAM’s) offer a straightforward approach to tailoring the interfacial properties of metals, metal oxides and semiconductors. Noncovalent functionalization of single-layer graphene offers the possibility to finely tune surface chemistry for future applications in electronics. Polymerization of photochemically reactive molecules in a lying-down phase has been used to increase the strength of intermolecular interactions between long alkanes and HOPG substrates. Long-chain fatty acid derivatives with internal diyne groups yield a conjugated ene-yne polymer upon UV irradiation. Diyne lipids with phosphocholine (diyne PC) and phosphoethanolamine (diyne PE) groups offer a charged form of the head group that is robust towards …

Ultraviolet And Infrared Spectroscopy Of Synthetic Foldamers, Aib Homopeptides, And Solvated 1,2-Diphenylethane In The Gas Phase, Joseph R. Gord

Open Access Dissertations

The work presented here implements a supersonic jet expansion source to funnel the population of model peptides and solvated-bichromophore clusters into their low lying structural minima and to collisionally cool these minima to their respective zero-point vibrational levels. Single-conformation ultraviolet and infrared spectroscopy techniques are then used to probe these systems and investigate their electronic properties and uncover their intrinsic conformational preferences in the gas phase.

Model β/γ-peptides known as synthetic foldamers and aminoisobutyric acid (Aib) homopeptides incorporate structural constraints that are designed/known to impose particular structural motifs. Here the ability of a β/γ-dipeptide to replicate the backbone length of …

Advances In Raman Hyperspectral Compressive Detection Instrumentation For Fast Label Free Classification, Quantitation And Imaging, Bharat R. Makani

Open Access Dissertations

Multiple prototypes of hyperspectral compressive detection (CD) Raman spectrometers have previously been constructed in the Ben-Amotz lab and have proven to be useful for fast, label-free chemical identification, quantitation and imaging. The CD spectrometer consists of a volume holographic grating (VHG) that linearly disperses the Raman photons into its component wavelengths and all wavelengths are focused onto a digital micromirror devise (DMD). The DMD is an optical modulator that consists of an array of programmable 10μm mirrors that can reflect photons in either +12° or -12° to the incoming light. The DMD is tilted such that the +12° photons go …

Coupling Qualitative And Quantitative Analyses Of Pharmaceutical Materials Enabled By Second Harmonic Generation Microscopy, Paul D. Schmitt

Open Access Dissertations

The detection and characterization of crystallinity is critical throughout the drug development process. From the initial establishment of an active pharmaceutical ingredient’s (API) crystal structure to stability testing and quality control, the phase of an API affects the solubility, bioavailability, stability, and efficacy of a drug product. Second harmonic generation (SHG) microscopy has recently been developed as a selective and rapid method for imaging crystallinity in drug formulations. While SHG microscopy can enable the high signal-to-noise (SNR) detection of crystallinity, the intrinsic chemical information content within SHG images is relatively low. In cases of trace crystallinity and/ or small crystal …

Determination Of Kinetic Parameters Of Equilibrium Peracetic Acid And Hydrogen Peroxide To Calculate Self-Accelerating Decomposition, Ricky Mittiga

Multidisciplinary Studies Theses

Determination of Kinetic Parameters of Equilibrium Peracetic Acid and Hydrogen Peroxide to Calculate Self-Accelerating Decomposition Temperature

Peracetic acid is a simple molecule that works as a powerful oxidant in many applications including food safety and water disinfection. The synthesis of the compound is fairly well understood due to its straightforward synthesis by mixing acetic acid and hydrogen peroxide. However, the decomposition of the compound has not been well studied. Few sources are available to provide kinetic data for the decomposition along with data that shows when the compound will undergo a self-accelerated decomposition that could lead to disastrous effects.

This …

Heparin-Peptide Interactions, Jacqueline Anastasia Morris

Graduate Theses and Dissertations

Heparin is a polydispersed sulfated molecule that is part of the family called glycosaminoglycans found in the extracellular matrix and cell surfaces. This molecule is extremely important for the activation of proteins and protein-receptor interactions that are responsible for downstream cell signaling pathways. Heparin has been isolated from porcine intestine and used as an anticoagulant for the prevention of embolisms, heart thrombosis, and clotting during heart surgeries. This so-called miracle drug was in use until 2008, when isolated batches were found to be contaminated with other glycosaminoglycans similar to heparin. From 2008, there has been a dire need for a …