Analytical Chemistry Commons^™

Investigating The Interactions Of The Iron-Sulfur Mitochondrial Protein, Mitoneet With Its Binding Partners, Ebenezer Osei Newton

Graduate Theses, Dissertations, and Problem Reports

MitoNEET belongs to the CDGSH Iron-Sulfur Domain (CISD)-gene family of proteins and is a [2Fe-2S] cluster-containing protein found on the outer membrane of mitochondria. The specific functions of mitoNEET/CISD1 remain to be fully elucidated, but the protein is involved in regulating mitochondrial bioenergetics in several metabolic diseases. Unfortunately, drug discovery efforts targeting mitoNEET to improve metabolic disorders are hampered by the lack of ligand-binding assays for this mitochondrial protein. We have developed a protocol amenable for high-throughput screening (HTS) assay, by modifying an ATP fluorescence polarization method to facilitate drug discovery targeting mitoNEET. Based on our observation that adenosine triphosphate …

Investigation Of Early Complex Formation Of Huntingtin Protein With And Without Lipids, Alyssa R. Stonebraker

Graduate Theses, Dissertations, and Problem Reports

Huntington’s disease (HD) is a fatal neurodegenerative disease caused by the expansion of the polyglutamine (polyQ) domain of the huntingtin protein (htt). The expansion of the polyQ domain beyond a threshold of approximately 35 repeats triggers complex toxic aggregation mechanisms and results in altered interactions between htt and lipid membranes. Many factors modulate these processes. One such modulator includes sequences flanking the polyQ domain, most notably the first 17 amino acids at the N-terminus of the protein (Nt17), and environmental factors including the presence of membranous structures. Nt17 has the propensity to form an amphipathic a-helix in the presence of …

Enhancing The Forensic Comparison Process Of Common Trace Materials Through The Development Of Practical And Systematic Methods, Meghan Nicole Prusinowski

Graduate Theses, Dissertations, and Problem Reports

An ongoing advancement in forensic trace evidence has driven the development of new and objective methods for comparing various materials. While many standard guides have been published for use in trace laboratories, different areas require a more comprehensive understanding of error rates and an urgent need for harmonizing methods of examination and interpretation. Two critical areas are the forensic examination of physical fits and the comparison of spectral data, which depend highly on the examiner’s judgment.

The long-term goal of this study is to advance and modernize the comparative process of physical fit examinations and spectral interpretation. This goal is …

The Influence Of Instrumental Sources Of Variance On Mass Spectral Comparison Algorithms, Isabel Cristina Galvez Valencia

Graduate Theses, Dissertations, and Problem Reports

Current search algorithms for the identification of substances based only on their electron ionization mass spectra provide the correct compound as their top result approximately 80% of the time. One contributing factor to the ~20% deviation in the first-hit recognition rate is that traditional algorithms work by comparing the unknown spectrum to an ‘ideal’ or consensus spectrum of each reference compound. The inclusion of replicate reference spectra in a database has been shown to improve the probability of ranking the correct identity in the number one position, but the variance in ion abundances caused by different conditions or different instruments …

Heterogeneous Oxidation Of Multi-Component Aqueous Organic Aerosols: The Effect Of Transport Phenomena And Reaction Compartment On Reaction Kinetics., Tadini Wenyika Masaya

Graduate Theses, Dissertations, and Problem Reports

The surface-bulk partitioning of small organic molecules in aqueous droplets was investigated using molecular dynamics. The air-particle interface was modeled using a 80-Å cubic water box containing series of organic molecules and surrounded by gaseous OH radicals. The properties of the organic solutes within the interface and the water-bulk were examined at a molecular-level using density profiles and radial pair distribution functions. Molecules containing only polar functional groups such as urea and glucose are found predominantly in the water bulk, forming an exclusion layer near the water surface. Substitution of a single polar group by an alkyl group in sugars …

Characterizing The Effects Of Solvent And Analyte Properties On Ionization Efficiency By Novel Field-Free And Field-Enabled Ionization Techniques, Kinkini Udara Jayasundara

Graduate Theses, Dissertations, and Problem Reports

In recent years the mass spectrometry (MS) area of field and/or direct analysis has grown dramatically. As a result, field-portable and miniaturized mass spectrometers, introduced only a few years ago, are proliferating. A highly desired feature for field-portable MS, or in-field analysis, is the ability to use ionization techniques requiring very little sample preparation as well as an ability to generate the ions under ambient conditions. Recently, a new ambient ionization technique termed vibrating sharp-edge spray ionization (VSSI) has been introduced which overcomes the field-portable limitations of other spray-based methods including the requirements for auxiliary components (e.g., nebulizing gas and …

Capillary Electrophoresis: Method Development And Application In Biomolecule Analysis, Lindsay Marie Veltri

Graduate Theses, Dissertations, and Problem Reports

Abstract

Capillary Electrophoresis: Method Development and Application in Biomolecule Analysis

Lindsay Veltri

Biomolecule analysis is essential in disease diagnostics and the development of therapeutic agents. There is a vast array of methods available for biomolecule analysis, however, capillary electrophoresis is well-suited due to minimal sample consumption (~nanoliters of solution) and fast analysis times. In this report, capillary electrophoresis was used to analyze glycosylation of therapeutic proteins. Additionally, a capillary electrophoresis-mass spectrometry method is reported for the analysis of proteins.

Post-translation protein modifications like glycosylation, play an important in protein structure and function. Modifications of protein glycosylation can lead to improved …

Electrochemical And Mass Spectrometry Methods For Identification Of Gunshot Residues (Gsr) In Forensic Investigations, Kourtney A. Dalzell

Graduate Theses, Dissertations, and Problem Reports

Gun violence continues to be one of most significant challenges straining the USA society causing thousands of human lives lost every year. In 2020 alone, firearm-related incidents including homicide, accidents, and suicides, reached a staggering number of over 43,000.^1,2 With the increase in these types of incidents, several service areas in crime laboratories are heavily impacted by the number of cases run on a yearly basis. These include firearm examinations, gunshot residue (GSR) analysis, bullet hole identification, and shooting distance determination, which are crucial to support a criminal investigation and, overall, the justice system in our country. These areas …

Development Of Capillary Vibrating Sharp-Edge Spray Ionization For Improving Continuous Flow Mass Spectrometry Analysis, Chong Li

Graduate Theses, Dissertations, and Problem Reports

Capillary Vibrating Sharp-Edge Spray Ionization (cVSSI) is new ionization technique developed in the year of 2018. This ionization technique has attractive features such as simplicity, compactness, ease of manipulation, low costs, compatible with continuous flow, etc. However, the development of high performance cVSSI for mass spectrometry analysis is a process that needs unremitting optimizations. In this dissertation, I demonstrate the development of cVSSI for improving continuous flow mass spectrometry analysis. The chapter 2 focuses on improving the ionization efficiency of cVSSI through reducing the droplet size. Three strategies were tested to reduce the droplet size of VSSI. The most effective …

Analysis Of Forensically Relevant Evidence Using Electrochemistry, Spectroscopy, And Mass Spectrometry Tools, Colby Edward Ott

Graduate Theses, Dissertations, and Problem Reports

Forensic science relies on the use of multiple techniques in the assessment of evidence to increase the accuracy and reliability of the results. However, with the rapidly changing drug landscape due to the introduction of novel psychoactive substances, many traditional screening methods are no longer sensitive or selective enough for use. Additionally, many screening methods such as chemical color tests are prone to false positive and negative results and are subjective. Therefore, the goal of this dissertation was to develop a novel analytical scheme that can provide a more efficient, rapid, and sensitive method that will facilitate adoption in the …

Assessment Of Quechers Extraction Protocol For The Lc-Ms/Ms Detection Of Emerging Fentanyl Analogs In Biological Specimens For Clinical And Forensic Purposes, Kylea M. Morris

Graduate Theses, Dissertations, and Problem Reports

Drug abuse within the United States is a dynamic and pervasive issue that affects the quality and life expectancy of our society. One of the major drug classes that are constantly utilized is opioids. Opioids are prescribed for pain management in patients suffering from cancer and other medical illnesses. Long-term use of opioids could lead to tolerance in humans, which poses a risk of reaching fatal overdose levels. Unfortunately, opioids are abused recreationally, and in some instances, individuals are unaware of the presence of dangerous synthetic drugs like fentanyl, hidden in materials such as heroin, cocaine, oxycodone, and methamphetamine. Recent …

Development Of Vibrating Sharp-Edge Spray Ionization (Vssi) Methods For Mass Spectrometry Analysis And Imaging, Nandhini Ranganathan

Graduate Theses, Dissertations, and Problem Reports

Mass Spectrometry (MS) is one of the widely used tools for chemical detection down to attomole concentrations for certain proteins. Ionization sources are a critical component for MS analysis. One of the major ionization methods is electrospray ionization (ESI), which remains a gold standard for proteins and peptides. ESI uses voltages up to ~4 kV to produce ions from solubilized molecules. Recently, a novel ionization method termed vibrating sharp-edge spray ionization (VSSI) that nebulizes liquids efficiently at the edge of a vibrating glass slide has been reported. The work in this thesis leverages the capabilities of VSSI for continuous flow-based …

Enhancing Negative-Ion Native Mass Spectrometry With Field-Assisted Capillary Vibrating Sharp-Edge Spray Ionization (Cvssi), Kushani Udeshika Attanayake

Graduate Theses, Dissertations, and Problem Reports

Although the birth of native mass spectrometry (native MS) occurred only several years after the development of electrospray ionization (ESI), it is yet considered an emerging technique for MS-based studies. This stems in part from challenges associated with efficient ionization of biopolymers. Although steady gains in ion production for native structure characterization have been secured primarily with the use of nanoelectrospray ionization (nESI), under negative polarity, the ionization efficiency can be extensively reduced due to an effect called “corona discharge”. The corona discharge occurs at the tip of ESI emitters because of free electron acceleration in the high-field region produced …

Online Ultra-High Performance Liquid Chromatography-Charge Transfer Dissociation-Mass Spectrometry (Uhplc-Ctd-Ms) Of Complex Mixtures Of Oligosaccharides, Praneeth M. Mendis

Graduate Theses, Dissertations, and Problem Reports

Abstract

Online Ultra-High Performance Liquid Chromatography-Charge Transfer Dissociation-Mass Spectrometry (UHPLC-CTD-MS) of Complex Mixtures of Oligosaccharides

Praneeth M. Mendis

Complex carbohydrates make up more than half the biomass on earth, and they are crucial to a wide range of processes in living organisms. When polysaccharides and glycans are enzymatically digested into manageable units called oligosaccharides, they typically consist of 2-20 linear or branched sugar units. The detailed structural analysis of oligosaccharides assists in the identification of structural and chemical properties of the polymers from which they derive. Tandem mass spectrometry (MS/MS) is a key technique used in oligosaccharides structural characterization. Within …

Modified Firearm Discharge Residue Analysis Utilizing Advanced Analytical Techniques, Complexing Agents, And Quantum Chemical Calculations, William J. Feeney

Graduate Theses, Dissertations, and Problem Reports

The use of gunshot residue (GSR) or firearm discharge residue (FDR) evidence faces some challenges because of instrumental and analytical limitations and the difficulties in evaluating and communicating evidentiary value. For instance, the categorization of GSR based only on elemental analysis of single, spherical particles is becoming insufficient because newer ammunition formulations produce residues with varying particle morphology and composition. Also, one common criticism about GSR practitioners is that their reports focus on the presence or absence of GSR in an item without providing an assessment of the weight of the evidence. Such reports leave the end-used with unanswered questions, …

Valorization Of Xylan In Agroforestry Waste Streams, Harrison Appiah

Graduate Theses, Dissertations, and Problem Reports

Valorization of Xylan in Agroforestry Waste Streams.

Harrison Appiah

Microwave-assisted deep eutectic solvent and gamma-valerolactone metallic chloride catalyzed conversion of xylan to furfural were investigated using a 2x3 factorial experimental design at two levels of percent microwave power, reaction time, and catalyst concentration. The levels of each factor studied were (20%, 60% microwave power, 2, 4 minutes, and 10, 20mg) respectively. The effect of three metallic chloride catalysts (LiCl, FeCl3.6H20, CuCl2) on the conversion of xylan to furfural was also investigated. The gamma-valerolactone-ferric chloride sent system exhibited the highest mean yield of furfural (56.50%). The next highest furfural yield of …

Unique Biological Applications Of Charge Transfer Dissociation Mass Spectrometry, Halle M. Edwards

Graduate Theses, Dissertations, and Problem Reports

The ever-changing landscape of mass spectrometry is driven by gaps in knowledge, and one of the biggest driving forces is the desire to understand the structure and dynamics of biomolecules in living organisms. New and better methods of tandem mass spectrometry are often at the heart of technological developments. Some fragmentation methods are limited to expensive FTICR instruments, some techniques are limited multiply charged precursors, and others are limited to breaking only the weakest bonds in precursor ions; all of which support the pursuit of new activation methods. Charge transfer dissociation (CTD) addresses some of these concerns by providing structurally …

Fundamentals And Applications Of Charge Transfer Dissociation Mass Spectrometry, Zachary Joseph Sasiene

Graduate Theses, Dissertations, and Problem Reports

The recent surge in the analysis of biomolecules has driven the need for robust, versatile, sensitive, and accurate techniques such as tandem mass spectrometry for compound structural elucidation. Many fragmentation techniques have been developed over the years, but each has their own limitations, such as the loss of post-translational modifications (PTMs), inability to fragment singly charged precursor ions or cost prohibitiveness. To help fill this gap, a novel fragmentation technique called charge transfer dissociation (CTD) has been developed to fragment stored precursor ions through radical-driven fragmentation processes using kiloelectronvolt reagent cations. CTD has shown success in the analysis of proteins, …

Improving Characterization Of Small Molecules Using Enhanced Molecular Reaction And Ionization Techniques, Sandra N. Majuta

Graduate Theses, Dissertations, and Problem Reports

Metabolomics is an emerging “omics” field, which is comprised of the study of small molecule metabolites in biological systems. It can be argued that the abundances of metabolites within biological samples, such as tissue and plasma, are indicative of various physiological states. Thus, metabolomics analysis has the potential in the clinical scientific field to be an effective tool for early disease diagnosis as well as for proposing and monitoring new treatments for diseases. However, full characterization of the metabolome complement is often hampered by the wide diversity of metabolites, which also exhibit an extremely large concentration range in biological samples. …

Employing Exoglycosidase And Transferase Enzymes In Capillary Nanogel Electrophoresis For The Determination Of N-Glycan Linkages And Enzyme Michaelis-Menten Constants., Lloyd Bwanali

Graduate Theses, Dissertations, and Problem Reports

As a post translational modification protein glycosylation plays a crucial role in protein signaling, binding, kinetics and folding. In disease diagnosis and prognosis, monitoring glycosylation has been identified as a biomarker. Sialylation and sialic acid linkage in N-glycans are markers of cancers including liver, pancreatic and kidney cancer. Quantification of sialic acid linkage is analytically challenging because of the diverse linkages and the presence of heterogenous branching. A capillary electrophoresis method is reported that integrates a unique combination of enzymes and lectins to modify sialylated asparagine-linked glycans (N-glycans) in real time in the capillary so that N-glycan structures containing α2–6-linked …

Characterization Of Modern Ammunition And Background Profiles: A Novel Approach And Probabilistic Interpretation Of Inorganic Gunshot Residue, Korina Layli Menking-Hoggatt

Graduate Theses, Dissertations, and Problem Reports

Gunshot residue (GSR) can provide essential clues in gun-related investigations. The standard practice for GSR analysis uses SEM-EDS, with the capability for single particle elemental and morphological analysis. However, the method is time-consuming and based on categorical classification models without considering case circumstances. Therefore, complementary and more encompassing methods are needed to improve evidence interpretation of modern ammunition. This research aims to fill these demands by developing standard materials and alternative methods to characterize and interpret IGSR.

This study developed primer GSR (pGSR) standards from sixty discharged primers that were fully characterized by three techniques. The number of GSR particles, …

Analysis Of Cell Signaling Perturbations In Response To Chronic Localized Infections, Amber Nicole Prince

Graduate Theses, Dissertations, and Problem Reports

The tissue-level response to pathogens involves an intricate series of signal transduction events, influenced by immune and healing mediators that alert the host to danger and eliminate the infection. Disruptions to normal signaling events can compromise the host’s ability to respond and lead to the development of chronic infections that cannot be resolved without clinical intervention. Prolonged inflammation due to chronic infection can damage tissues and compromise healing processes, thus, the interactions of immune and healing mediators in signaling cascades are intimately linked to tissue health outcomes. Studying signaling networks relevant to these responses provided a more thorough understanding of …

Harnessing Acoustic Streaming For Bioanalysis In Microfluidics, Xiaojun Li

Graduate Theses, Dissertations, and Problem Reports

In the past few decades, microfluidic technology has been developed rapidly in both fabrication methods and multifunctionality integrations, making it a powerful tool for a wider variety of biological applications. The device fabrication method has expanded from conventional polymer-based micro devices to 3D-printed micro devices, and allows multiple functions such as electric, optic, magnetic and acoustic to be integrated on a single platform. This dissertation focuses on method development of acoustic streaming-based microfluidics in bioanalysis such as immunoassay, enzyme kinetics and DNA fragmentation analysis. In this dissertation, a micromixer was developed based on acoustic streaming generated from sharp-edge structure vibration …

Genetic And Biochemical Characterization Of Ergot Alkaloid Synthesizing Fungi And Their Symbionts, Matthew Duane Maust

Graduate Theses, Dissertations, and Problem Reports

Ergot alkaloids are fungal tryptophan derived toxins which affect mammalian circulation and neurotransmission. These compounds are biosynthesized by a conserved genetic pathway, known as the ergot alkaloid synthesis (EAS) pathway by fungi belonging to the ascomycete families Trichocomaceae and Clavicipitaceae. Several Ipomoea species and related plants in the morning glory family harbor vertically transmitted symbiotic fungi in the genus Periglandula, also members of Clavicipitaceae, that produce ergot alkaloids. Metabolomic analysis of seeds identified a previously uncharacterized glycoside form of the pharmaceutically important ergot alkaloid, ergonovine. Several species belonging to the fungal genus Metarhizium have recently been shown to have the …

The Effects Of Membrane Physicochemical Properties On Huntingtin Membrane Association And Downstream Aggregation, Maryssa Beasley

Graduate Theses, Dissertations, and Problem Reports

Huntington’s Disease (HD) is a fatal neurodegenerative disorder caused by an expanded glutamine repeat region (polyQ) within the huntingtin protein (htt). As a result of the expanded polyQ domain, htt associates into a variety of toxic aggregate species. The polyQ domain of htt is flanked at the N-terminal end by 17 amino acids (Nt17) that adopt an amphipathic α-helical structure in the presence of binding partners such as lipid membranes. In addition to comprising a lipid binding domain, the Nt17 amphipathic α -helix has been directly implicated in htt aggregation initiation via self-association with other Nt17 α -helices. Due to …

Structural Characterization Of Emerging Synthetic Drugs, Jay Tyler Davidson

Graduate Theses, Dissertations, and Problem Reports

The identification of well-characterized seized drugs is performed thousands of times a day in the United States; however, the expanding use of emerging synthetic drugs is creating a growing problem for both toxicological and seized drug analyses. Two of the most rapidly growing areas of emerging synthetic drugs are synthetic cathinones and fentanyl-related compounds (FRCs). In this work we demonstrate the combination of multi-stage mass spectrometry (MSⁿ), accurate mass measurements with high-resolution mass spectrometry (HRMS), and isotopic labeling for the structural characterization of synthetic cathinones and fentanyl analogs. The deliverables of this research include the identification of conserved …

Capillary Electrophoresis Analysis Of Proteins Using Phospholipid Based Materials, Cassandra L. Crihfield

Graduate Theses, Dissertations, and Problem Reports

Capillary electrophoresis has many advantages that make it a powerful technique for the analysis of proteins, which is challenging due to the natural heterogeneity of proteins. The small sample volume required for each analysis (nano- and pico-liter), fast separation times (<30 >min), and ability to couple the separation to mass spectrometry are all factors that make capillary electrophoresis an ideal technology for protein separations. Capillary zone electrophoresis and capillary gel electrophoresis are the two most commonly employed modes for protein analysis and allow for rapid, high resolution separations that can be automated. This makes capillary electrophoresis ideal for meeting the …

Development And Implementation Of A Novel Voltage-Free Interface For Capillary Electrophoresis-Mass Spectrometry Separations Of Proteins, Courtney J. Kristoff

Graduate Theses, Dissertations, and Problem Reports

Capillary electrophoresis-mass spectrometry is a powerful technique for high-throughput and high efficiency separations combined with structural identification. Electrospray ionization is the primary interface used to couple capillary electrophoresis to mass analyzers; however, improved designs continue to be reported. A new interfacing method based on vibrating sharp-edge spray ionization is presented in this work to overcome the challenges of decoupling applied voltages and to enhance the compatibility with separations performed at near-neutral pH. The versatility and ease of use of this ionization source is demonstrated using β-blockers, peptides, and proteins. The cationic β-blocker pindolol was injected electrokinetically and detected at concentrations …

Protein/Peptide Characterization Using Mass Spectrometry And Molecular Dynamics Simulations, Ahmad Kiani Karanji

Graduate Theses, Dissertations, and Problem Reports

Mass spectrometry (MS) based-techniques and molecular dynamics (MD) simulations have been used to characterize protein/peptide structure as well as their interactions with lipid vesicles and detergents. Chapter 1 introduces an introduction to the concepts and tools that were used in this work. In Chapter 2, the dominant gas-phase conformer of [M+3H]3+ ions of the model peptide Acetyl-PSSSSKSSSSKSSSSKSSSSK are examined with ion mobility spectrometry (IMS), gas-phase hydrogen deuterium exchange (HDX), and mass spectrometry (MS) techniques. This section furthers the development of a protein structural prediction tool by providing information about gas-phase ion conformers of two model peptides having different solution conformational …

Compound-Specific Isotope Analysis Of Amino Acids In Biological Tissues: Applications In Forensic Entomology, Food Authentication And Soft-Biometrics In Humans, Mayara Patricia Viana De Matos

Graduate Theses, Dissertations, and Problem Reports

In this work we demonstrate the power of compound-specific isotope analysis (CSIA) to analyze proteinaceous biological materials in three distinct forensic applications, including: 1) linking necrophagous blow flies in different life stages to their primary carrion diet; 2) identifying the harvesting area of oysters for food authentication purposes; and 3) the ability to predict biometric traits about humans from their hair.

In the first application, we measured the amino-acid-level fractionation that occurs at each major life stage of Calliphora vicina (Robineau-Desvoidy) (Diptera: Calliphoridae) blow flies. Adult blow flies oviposited on raw pork muscle, beef muscle, or chicken liver. Larvae, pupae …