Physical Sciences and Mathematics Commons^™

Electrochemical And Surface Compositional Studies On Uranium Dioxide, Mayuri Razdan

Electronic Thesis and Dissertation Repository

This thesis describes electrochemical and surface compositional studies performed on a number of simulated nuclear fuel (SIMFUEL) materials under conditions relevant to permanent disposal of spent nuclear fuel in a geologic repository. This is important since a number of critical issues have been identified in the event of waste container failure. The research performed was mainly focused in three areas: (i) the influence of low pH on the surface chemistry of UO₂, since acidity could develop within corrosion product deposits and flaws in the fuel; (ii) the combined influence of dissolved H₂ and H₂O_{2 …}

Microfluidics Guided By Redox-Magnetohydrodynamics (Mhd) For Lab-On-A-Chip Applications, Vishal Sahore

Graduate Theses and Dissertations

Unique microfluidic control actuated by simply turning off and on microfabricated electrodes in a small-volume system was investigated for lab-on-a-chip applications. This was accomplished using a relatively new pumping technique of redox-magnetohydrodynamics (MHD), which as shown in this dissertation generated the important microfluidic features of flat flow profile and fluid circulation. MHD is driven by the body force, FB = j × B, which is the magnetic part of the Lorentz force equation, and its direction is given by the right hand rule. The ionic current density, j, was generated in an equimolar solution of potassium ferri/ferro cyanide by applying …

Demonstration Of A Targeted Proteome Characterization Approach For Examining Specific Metabolic Pathways In Complex Bacterial Systems, Adam Justin Martin

Masters Theses

Multiple Reaction Monitoring (MRM) is a powerful tandem mass spectrometry (MS/MS) tool frequently implemented in proteomic studies to provide targeted analysis of proteins and peptides. The selectivity that MRM delivers is so strong that it provides the quadrupole mass spectrometers (QQQ), on which it is commonly employed, with pertinence to proteomic studies that they would otherwise lack for their relatively low resolution. Additionally, this increased level of selectivity is sufficient enough to supplant complicated fractionation techniques, additional dimensions of chromatography, and 24 hour long MS/MS experiments in simplistic biological samples. But there is a deficiency of evidence to determine the …

Lipid Production By Microalgae Treating Municipal Wastewater, James Edward Kelley

Master's Theses

Microalgae hold much promise as a feedstock in liquid biofuel production. Lipid content of microalgae cells range from 30-80% dry weight of biomass. It is projected that microalgae can produce between 1,000-6,500 gallons/acre/year of oil. Currently, production of industrial algae operates in open raceway ponds that use minimal capital and energy inputs to culture algae. Raceway ponds can also be used to grow microalgae from municipal waste streams. Although high biomass productivity can be achieved in these systems, there remains a large production gap between large volumes of biomass cultivation and high lipid content from microalgae cells. Low lipid content …

Crevice Corrosion Behavior Of Ni-Cr-Mo-W Alloys In Aggressive Environment, Ajit K. Mishra

Electronic Thesis and Dissertation Repository

Ni-Cr-Mo (W) alloys, having an optimum concentration of Cr. Mo and W, are highly corrosion resistant alloys which do not fail by uniform corrosion in aggressive environments. However, when creviced at high applied potential and high temperatures, these materials can be susceptible to crevice corrosion. This study focuses on a family of seven commercial Ni-Cr-Mo (W) alloys containing various amounts of Cr, Mo and W.

Different electrochemical techniques were used to determine the characteristic potentials and temperature which indicate susceptibility to crevice corrosion, and to investigate the individual and synergistic roles of major and minor alloying elements. The corroded alloys …

Electrochemical Reduction Of Aqueous Uranium, Jonathan M. Scaggs

Boise State University Theses and Dissertations

The electrochemical reduction of uranium in acidic aqueous environments with the express purpose of generating U(III) consistently is critically evaluated. Generating U(III) in an aqueous environment is difficult and extremely unstable and has historically been difficult to achieve and isolate for further investigation. The electrochemical cell, electrodes, supporting electrolytes, and pH’s are all reviewed and evaluated for the purpose of optimizing the systemic requirements to electrochemically generate U(III). Several new types of electrochemical cells to include two new spectroelectrochemical for UV-Vis and FT-Raman investigation were designed and tested for the purpose of analyzed the redox species of aqueous uranium generated …

Construction And Demonstration Of A Tandem Mass Spectrometer Based Instrument For Cold Ion Spectroscopy, James Gerhardt Redwine

Open Access Dissertations

A new instrument incorporating ion trap based tandem mass spectrometry and cold ion UV and UV-IR double resonance spectroscopy has been developed at Purdue University for the study of gas phase, biologically relevant ions. The instrument incorporates multiple quadrupole linear ion trap mass analyzers to prepare and isolate the precursor ions as well as to analyze the resultant photofragments. A 22-pole ion trap cooled to 5 K via a closed cycle helium cryostat is used to cool the ions for spectroscopic interrogation. Results show the vibrational and rotational temperature of a wide assortment of ions to be 12±2 K.

The …

Instrumentation, Applications And Fundamentals Of Plasma Ionization Of Organic Molecules From Surfaces, Joshua Scott Wiley

Open Access Dissertations

Various aspects of the interaction of low-temperature plasma (LTP) ambient ionization with organic molecules and surfaces are discussed. As an application, LTP-MS has been used for the analysis of pesticides directly from fruits and vegetables revealing low parts per billion limits of detection (LODs). Due to low power and gas requirements, a battery-operated and handheld LTP probe was developed for the point-and-shoot MS analyses. Handheld LTP was compared with large-scale LTP on a benchtop and miniature MS revealing similar LODs for both. Long-distance ion transport up to one meter was also demonstrated with flexible tubing for non-proximate sample interrogation. Fundamentals …

Development Of Quantitative Ft- Ir Methods For Analyzing The Cure Kinetics Of Epoxy Resins, Sang Ha Son

Open Access Dissertations

Epoxy thermosets are important engineering materials with applications in coating, adhesives, packaging and as structural components in a variety of advanced engineering products. The ultimate performance of polymer critically depends upon the details of the cure chemistry used to produce the thermoset. In order to better understand and monitor the cure chemistry, quantitative analysis of the FT-IR response has been developed for describing the epoxy-amine curing reaction as well as monitoring the hydrogen bonding that occurs in these systems The FT-IR analysis includes (i) quantitative deconvolution of complex peaks into individual spectral contributions, (ii) peak identification via DFT analysis and …

Development Of Isotags For Nmr Based Metabolite Profiling And Applications, Fariba Tayyari

Open Access Dissertations

NMR spectroscopy is a powerful analytical tool for both qualitative and quantitative metabolite profiling analysis. However, accurate quantitative analysis of biological systems especially using one dimensional NMR has been challenging due to signal overlap. In contrast, the enhanced resolution and sensitivity offered by chemoselective isotope tags have enabled new and enhanced methods for detecting hundreds of quantifiable metabolites in biofluids using NMR spectroscopy or mass spectrometry. In this thesis we show improved sensitivity and resolution of NMR experiments imparted by 15N and 13C isotope tagging which enables the accurate analysis of plasma metabolites. To date, isotope tagging has been used …

Silica Colloidal Crystals As Emerging Materials For The High-Throughput Sizing Of Proteins By Packed Capillary Electrophoresis, Nadine K. Njoya

Open Access Dissertations

Protein heterogeneity is currently one of the leading problems in formulation of therapeutic proteins. The effectiveness of therapeutic proteins is diminished when they exhibit heterogeneity due to aggregates and degradation by-products. Furthermore, guidelines set forth by the FDA require therapeutic proteins to have high stability as well as high purity. With development time on the order of years and costs incurred in the millions, pharmaceutical companies are investing more time in finding fast and efficient ways to screen for protein heterogeneity. Current methods such as native polyacrylamide gel electrophoresis (PAGE), size-exclusion chromatography (SEC) and capillary electrophoresis (CE) are time consuming, …

Utilizing Electron Microscopy And Spectroscopy Methods To Understand Water Structure And Water Doping, Lior Miller

Open Access Dissertations

Water is the second most common element in the universe and the most studied material on earth. Most of the studies concerning water are from the fields of chemistry and biology. Hence, the structure of water molecules and short range order and interactions are well characterized and understood. However, the collective arrangement of water molecules and the long range order are still missing. Understanding of this long range order in water is needed, as it is the key to many water activities.

To fill this gap, this study utilizes a new direct method for characterization of water in the vapor …

Spectroscopic Characterization Of The Water-Oxidation Intermediates In The Ru-Based Catalysts For Artificial Photosynthesis, Dooshaye Moonshiram

Open Access Dissertations

Utilization of sunlight requires solar capture, light-to-energy conversion and storage. One effective way to store energy is to convert it into chemical energy by fuel-forming reactions, such as water splitting into hydrogen and oxygen. Ruthenium complexes are among few molecular-defined catalysts capable of water splitting. Insight into the mechanism of their action will help to design future robust and economically feasible catalysts for light-to-energy conversion. Mechanistic insights about the design of such catalysts can be acquired through spectroscopic analysis of short-lived intermediates of catalytic water oxidation. Development of time-resolved approaches through stopped flow UV-Vis Spectroscopy to follow the catalysis of …

Top-Down Interrogation And Characterization Of Biological Macromolecules, Yang Gao

Open Access Dissertations

Analytical mass spectrometry has been widely applied in the field of biomolecule identification and characterization. It provides fast, accurate and robust information relevant to the molecular mass, composition and structure of the target analytes.

This thesis is focused on the top-down analysis of various macrobiomolecules, nucleic acids and proteins, in the context of ion/ion reaction and gas-phase unimolecular dissociation. The first part of the thesis deals with gas phase fragmentation behavior of chemically modified oligonucleotides. Factors, such as the observation time-scale, the ion type and the energy deposition method, are explored using a quadrupole/time-of-flight mass spectrometer. Novel fragmentation pathway associated …

Mass Spectrometric Studies On The Primary Products Of Fast Pyrolysis Of Carbohydrates And The Molecular Structures Of Asphaltenes, And The Development Of A Rastering Probe For Laser-Induced Acoustic Desorption Into An Atmospheric Pressure Chemical Ionization Source, Matthew Robert Hurt

Open Access Dissertations

Mass spectrometry (MS) has proven invaluable in the field of mixture analysis and structural elucidation. Tandem mass spectrometry (MS/MS) utilizing collision-activated dissociation (CAD) has become the technique of choice for structural elucidation of unknown analytes in mixtures. When coupled with gas chromatography (GC) or high performance liquid chromatography (HPLC), it allows for trace level analysis of mixture components. In spite of the utility of mass spectrometry in complex mixture analysis, it does have limitations. Traditional GC/MS methods used for the analysis of fast pyrolysis products cannot be used to analyze the primary products, thus limiting the knowledge that can be …

Structural Analysis Of Carbohydrates By Mass Spectrometry, Chiharu Konda

Open Access Dissertations

Protein glycosylation is a highly frequent post-translational modification. Glycosylation is actively involved in intermolecular and intercellular binding events that are important to a wide range of biological functions such as immunity and fertility. The unique functions of glycans are directly related to their structures. In order to fully characterize the structure of an unknown glycan, 5 levels of structural information is needed: sugar unit identity, anomeric configuration, linkage types, sequence, and branching location. One of the grand challenges limiting the advance of glycosciences is the lack of sensitive tools for detailed glycan structural analysis. Tandem mass spectrometry (MS/MS) is a …

Development Of A Field-Portable Miniature Mass Spectrometer Designed For In-Situ Analysis And Ion Trap Miniaturization, Paul Isaac Hendricks

Open Access Dissertations

Chemical analysis by mass spectrometry has become the gold standard due to the sensitivity, selectivity, and short analysis times that are afforded by the method. Advances in miniaturized vacuum systems, mass analyzers, electronics, and ionization sources have allowed for the development of field-portable mass spectrometers. The performance of portable instruments has received much attention for their utility in the detection of illicit drugs, explosives, environmental contaminants, therapeutic drugs, and more recently, biological tissues. Furthermore, detection of the aforementioned compounds can be completed at atmospheric pressures and in the presence of complex matrices and sample surfaces when used in conjunction with …

Development Of Mass Spectrometry-Based Methods For Quantitation And Characterization Of Protein Drugs: Transferrin As A Model Drug Delivery Vehicle, Shunhai Wang

Open Access Dissertations

In the last two decades, protein drugs have enjoyed a rapid growth and achieved a tremendous success in treating human diseases. However, the presence of physiological barriers greatly impedes the efficient delivery of such unconventional large molecule drugs, and therefore limits their clinical utility. An elegant way to address this challenge takes advantage of certain endogenous transporter proteins, such as human transferrin (Tf), whose ability to traverse physiological barriers has been extensively exploited. However, methods to investigate Tf-based drug delivery remained insufficient and unsatisfactory until recent development of quantitative mass spectrometry (MS). Hereby, MS-based methods have been developed and validated …

Studies Of The Charge Storage Properties Of Poly(Bithiophene) And Amorphous Carbon Nitride, Timothy Adam Forristal

Electronic Thesis and Dissertation Repository

The charge storage properties of several potential materials for battery applications have been investigated. Poly(bithiophene) films were prepared by potentiostatic and potentiodynamic electropolymerization methods. These films were then subject to galvanic cycles at varying rates and to various potential limits in order to explore their use as electrodes in a battery. Potentiodynamically deposited films retain their charge better over multiple cycles. By comparing to data collected by atomic force microscopy, we conclude that these films are less crystalline than films deposited potentiostatically and are better suited for the volume changes that occur when being charged and discharged.

Amorphous carbon nitride …

Electrochemical Evaluation Of Ionic Liquids For Biphasic Extraction Of Metal Ions Common To Spent Nuclear Fuel, Thomas J. Stockmann

Electronic Thesis and Dissertation Repository

Over the past 30 years electrochemistry at a liquid|liquid interface has been used to observe and quantify simple ion transfer (IT) as well as ligand assisted, or facilitated ion transfer (FIT) reactions. Liquid|liquid electrochemistry has developed to where valuable thermodynamic constants – for example, the metal ion to ligand stoichiometry and overall complexation constant, β, in FIT - can be evaluated using cyclic voltammetry (CV). Recently, ionic liquids (ILs) have shown greater metal ion extraction efficiencies in water-IL biphasic separations relative to conventional molecular organic solvents. In this way, they are of interest to the nuclear industry for applications …

Electrochemiluminescence Of Thienyltriazoles, Iridium Complexes, Au25 Clusters And Pbs Nanoparticles, Kalen N. Swanick

Electronic Thesis and Dissertation Repository

Electrogenerated chemiluminescence or electrochemiluminescence (ECL), produces light in the vicinity of a working electrode by the excited species of a luminophore formed via electron transfer between radical cations and anions, which are electrogenerated. In order for the ECL system to be efficient, the radicals must be stable in solution. This can be enhanced by adding co-reactants such as benzoyl peroxide (BPO) and tri-n-propylamine (TPrA) that produce strong oxidizing or reducing radicals upon redox reactions. ECL pairs electrochemical and spectroscopic methods and is a powerful analytical technique that is highly sensitive and selective.

A comprehensive, mechanistic study of ECL …

In Situ High-Pressure Studies Of Ammonia Borane Derivatives By Vibrational Spectroscopy, Zhihao Yu

Electronic Thesis and Dissertation Repository

Hydrogen has been regarded as a promising candidate to replace the conventional fossil fuel, and thus attracted enormous research efforts. However, hydrogen storage remains to be a big challenge to its practical applications. Consequently, the investigation of suitable hydrogen storage materials has become a highly active research field. Here we reported the first high pressure studies of three promising hydrogen storage materials, N(CH₃)₃BH₃, NH(CH₃)₂BH₃ and NaNH₂BH₃ by Raman and IR spectroscopy.

First, N(CH₃)₃BH₃ was studied at room temperature and pressures up …

Approaches For Improved Positional Proteomics, Yanjie Jiang

University of New Orleans Theses and Dissertations

Positional proteomics is emerging as an attractive technique to characterize protein termini, which play important biological roles in cells. Even with the advances in past decades, there still are areas for improvement. This thesis focuses on improving data quality and assignment confidence in positional proteomics.

A novel workflow was designed for the large-scale identification of protein N-terminal sequences. 4-sulfophenyl isothiocyanate (SPITC) is used for N-termini sulfonation; Upon higher energy collisional dissociation (HCD), SPITC peptides in electrospray ionization ESI generate predominately y-type ion series; such simplification of spectra enables the identification of N-termini with high fidelity. The presence of b_{1 …}

Analyses Of Multivitamins In Nutraceuticals By Reverse Phase Hplc With Dad, Elsd And Ms, Hsiang-Chi Huang

All Theses

ABSTRACT
Vitamins are essential to human beings and support long-term healthy lifestyle. They exist widely in food, but in small amount. Hence, dietary supplements and fortified food products are more and more popular in the nutritional markets. According to the Infant Formula Act of 1980, the range of each of the nutrients should fall within a specific range or above the required minimum, so there is an increasing interest of accurate measurement of vitamins, particularly the B-group vitamins. However, traditional methods for vitamin B analyses are time-consuming and often in poor accuracy. As a result, rapid and reliable analytical methods …

Optimization Of Sample Preparation In Matrix-Assisted Laser Desorption/Ionization (Maldi) Mass Spectrometry Of Macromolecules, Evgenia Akhmetova

Graduate Theses and Dissertations

New method for the matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) and Fourier transform mass spectrometry (MALDI-FTMS) analysis of low molecular weight polyvinyl acetate (PVAc) was developed and then applied to the characterization of commercially available chewing gum. The optimization of MALDI analysis of PVAc was achieved by investigating the influence of sample preparation variables such as the choice of solvent and choice of matrix-analyte ratio. It was demonstrated that the use of ethyl acetate as a solvent and 2,5-Dihydroxybenzoic acid as a matrix yielded the highest signal intensity for the pure polymer sample. The application of TOF technique did not …

Surface Tethered Pamam Dendrimers On Controlled Pore Glass As Color Release Sensors For Phosphates, Chang Liu

Master's Theses

Poly(amidoamine) dendrimer (PAMAM) are highly branched macromolecules with reactive amine groups in their interior and exterior. PAMAM dendrimers were attached to controlled pore glass (CPG) surfaces in order to create new functionalized surfaces and used as platforms for UV-vis and fluorescent sensing of phosphate substrates via indicator displacement assays (IDA).

CPG surfaces were first modified with different sized PAMAM dendrimers (generation 3.0, 4.0, and 5.0), then reacted with two strong metal-chelators: aminofunctionalized terpyridine (synthesized from 2,2’:6’,2’’-terpyridine) and Nα-Nα-bis(carboxymethyl)-L-lysine (Lys-NTA). First of all, Cu(II) metal ion binding capacities were measured on the surfaces. Second, two terminal group density tests, amine assay …

Resonance Hyper-Raman Characterization Of Nonlinear Chromophores, Christopher Bennett Milojevich

Doctoral Dissertations

Hyper-Raman spectroscopy is a nonlinear optical probe which can be used to explore the multi-photon properties of molecules. Three studies are presented in this dissertation. The first study is a combined experimental investigation of the surfaceenhanced hyper-Raman scattering with a theoretical study of the electronic states of the Rhodamine 6G molecule. This study demonstrates that hyper-Raman spectroscopy can be used to probe electronic states which are one-photon inaccessible. The second study involves a comparison of experimentally measured resonance hyper-Raman spectra to first-principles calculations of the resonance hyper-Raman scattering. This study shows the utility of coupling hyper-Raman spectroscopy and hyper-Raman calculations …

Quorum Sensing And Metabolism In Marine Environments, Amanda May

Doctoral Dissertations

Quorum sensing (QS) is a phenomenon that allows bacteria to communicate with each other. Small molecules known as autoinducers are synthesized and released by bacteria, and once enough members of the community are around to ensure survival, i.e. quorum, a phenotype, e.g. bioluminescence, is expressed. There are two types of QS molecules, intra- and inter-species.

S-4,5-Dihydroxy-2,3-pentanedione (DPD) is a byproduct of the activated methyl cycle which recycles methionine. This has led to the discussion as to whether DPD is a metabolic byproduct or is the interspecies signal as proposed previously. The detection and quantitation of DPD however, has not …

Analysis Of Ecological Change In Marine Ecosystems Via Novel Imaging And Spectroscopic Techniques On Microalgae Cells, Morgan Breonne Mcconico-Lewis

Doctoral Dissertations

With the increase in anthropogenic pollutants such as: atmospheric CO₂ [carbon dioxide], fossil fuel combustion and fertilizer run off, the fate of the environment is of great importance. Through industrialization, the greenhouse gas, CO₂, is a major contributor to global warming; while nitrogen based fertilizer, causes the production of toxins due to harmful algal blooms. Both chemical impacts dissolve into marine ecosystems effecting the chemical composition of organisms such as microalgae. Microalgae remediate these changes by sequestering carbon and nitrogen; thus there is a need to understand how these impacts affect the ecosystem by detecting the change …

Characterization Of The Distribution, Abundance, And Fate Of Metals In Sediment, April Grant

Theses and Dissertations

This research describes the mobility of heavy metals in river sediment through characterization of metal-sediment association by a sequential extraction procedure. The most abundant isotopes of As, Cd, Cu, Cr, Pb and Zn were measured by Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) in four sediment extraction phases: a) exchangeable, b) carbonate-bound, c) metal-oxide-bound, and d) organic-bound. The measured concentrations were compared to the Wisconsin Department of Natural Resources' "Sediment Quality Guidelines" to determine whether the metals were present at toxic levels. Two reference techniques, Potentiometric Stripping Analysis and Graphite Furnace Atomic Absorption Spectroscopy, were used to validate the concentrations of metals …