Analytical Chemistry Commons^™

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

Graduate Theses, Dissertations, and Problem Reports (ETD)

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, …

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 (ETD)

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 (ETD)

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, …

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

Graduate Theses, Dissertations, and Problem Reports (ETD)

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 (ETD)

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 …

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

Graduate Theses, Dissertations, and Problem Reports (ETD)

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 …

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 (ETD)

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 (ETD)

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, …

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

Graduate Theses, Dissertations, and Problem Reports (ETD)

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 (ETD)

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 …

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

Graduate Theses, Dissertations, and Problem Reports (ETD)

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 …

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

Graduate Theses, Dissertations, and Problem Reports (ETD)

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 …

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

Graduate Theses, Dissertations, and Problem Reports (ETD)

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 (ETD)

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 …

Electrochemical Detection Of Fentanyl Using Screen-Printed Carbon Electrodes With Confirmatory Analysis Of Fentanyl And Its Analogs In Oral Fluid Using Liquid Chromatography-Tandem Mass Spectrometry, Colby E. Ott

Graduate Theses, Dissertations, and Problem Reports (ETD)

Utilizing screen-printed carbon electrodes (SPCEs), a fast, simple, and sensitive approach toward the detection, identification, and quasi-quantitation of fentanyl was achieved both in an electrochemical cell and as a drop on the electrode surface. Electro-oxidation of fentanyl at the electrode was demonstrated using adsorptive stripping square-wave voltammetry between -0.5 V and +1.6 V with 100 mM Tris-HCl buffer at pH 8.5 as supporting electrolyte. Parameter optimization was conducted during method development to include supporting electrolyte and pH, electrochemical technique, pre-treatment and equilibration time, and various surface modifications. The simplest method utilizing an unmodified SPCE was determined to be appropriate for …

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 (ETD)

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 …

Non-Target Analyses Of Novel Psychoactive Substances; Inherent Variation In Gcms Relative Abundances And Gas Phase Hydrogen Deuterium Exchange Isomer Discrimination, Kristin Michelle Kelly

Graduate Theses, Dissertations, and Problem Reports (ETD)

Novel psychoactive substances (NPSs) are synthetically derived compounds designed to mimic the effects of other illicit drugs. An endless cycle of NPSs continually reach the drug market due to limitations in drug legislation creating two problems: (1) non-availability of standards and (2) multiple isobars indistinguishable even to high resolution mass spectrometry. Gas chromatography-mass spectrometry (GCMS) is the most common instrument used for compound identification in non-targeted seized drug analysis. Compound identification using this technique relies on mass spectra where the percent relative abundances (%RAs) of all m/z values are compared manually or searched against a library database. Lacking standards, laboratories …

Integrating Microscale Enzyme And Lectin Reactions Using Nanogel Assisted Capillary Electrophoresis, Srikanth Gattu

Graduate Theses, Dissertations, and Problem Reports (ETD)

Protein glycosylation is one of the most prevalent post-translational modifications which plays an important role in determining the structure, stability, and function of proteins. Changes in glycosylation patterns are a hallmark of cancer and other diseases. Characterizing glycosylation is difficult because these structures vary in their linkage and monomer sequence, which gives rise to vast microheterogenity that could affect the function of the molecule. A novel method using capillary gel electrophoresis by integrating microscale enzymes and lectin reactions in the capillary was developed to verify glycan structure by analyzing monosaccharides. Capillary electrophoresis (CE) improves upon conventional methods of glycan structure …

Plasmon-Enhanced Optical Sensing By Engineering Metallic Nanostructures, Peng Zheng

Graduate Theses, Dissertations, and Problem Reports (ETD)

The world’s booming population projected to reach 10 billion by 2050 causes enormous stresses on environmental safety, food supply, and healthcare, which in return threatens human civilizations. One of the most promising solutions lies at innovating point-of-care (POC) sensing technologies to conduct detection of environmental hazards, monitoring of food safety, and early diagnosis of diseases in a timely and accurate manner. The discovery of surface-enhanced spectroscopy in the 1970s has significantly stimulated research on light-matter interaction which gives rise to enhanced optical phenomena such as surface-enhanced Raman scattering (SERS), plasmon-enhanced fluorescence (PEF), and particularly, they have found enormous applications in …

Investigating Stress Response Across Integrated Biological Systems, Alice A. Han

Graduate Theses, Dissertations, and Problem Reports (ETD)

The impact that a stressor has on a living system, whether it is on a cellular, organ, or even a whole organism level, can affect the overall health of the system. Monitoring the biochemical response resulting from a stressful experience offers insight into the numerous potential outcomes ranging on the spectrum of survival and death. Accessing this information not only provides a heightened understanding of the biochemical adaptions that occur, but also allows for the development of prediction models (to assess prospective influences of the stressor) or potential therapeutic treatments (to alleviate adverse effects) using measurable, quantifiable, and comparable metrics. …