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Fourier Transform Ion Cyclotron Resonance Mass Spectrometry Applications For Metabolomics, Darcy Cochran, Robert Powers Aug 2024

Fourier Transform Ion Cyclotron Resonance Mass Spectrometry Applications For Metabolomics, Darcy Cochran, Robert Powers

Robert Powers Publications

Metabolomics is an interdisciplinary field that aims to study all metabolites < 1500 Da that are ubiquitously found within all organisms. Metabolomics is experiencing exponential growth and commonly relies on high-resolution mass spectrometry (HRMS). Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) is a form of HRMS that is particularly well suited for metabolomics research due to its exceptionally high resolution (105–106) and sensitivity with a mass accuracy in parts per billion (ppb). In this regard, FT-ICR-MS can provide valuable insights into the metabolomics analysis of complex biological systems due to unique capabilities such as the easy separation of isobaric and isomeric species, isotopic fine structure analysis, spatial resolution of metabolites in cells and tissues, and a high confidence (error) in metabolite identification. Alternatively, the large and complex data sets, long acquisition times, high cost, and limited access mainly through national mass spectrometry facilities may impede the …


High-Resolution Ion Mobility Analysis Of Isomeric Bile Acids Using Structures For Lossless Ion Manipulations (Slim) Im-Ms, Emmaleigh D. Efird Aug 2024

High-Resolution Ion Mobility Analysis Of Isomeric Bile Acids Using Structures For Lossless Ion Manipulations (Slim) Im-Ms, Emmaleigh D. Efird

All Theses

Bile acids are an essential part of the human digestion system and play an important role in lipid absorption, bacteria movement in the small intestine, and regulation of the farnesoid X receptor (FXR) and G protein-coupled bile acid receptors (GPBAR) responsible for homeostasis. They are synthesized in the liver, stored in the gallbladder and the excess is carried on to the small intestine. Many liver and intestinal diseases are diagnosed based on bile acid metabolism pathways and the structures of those bile acids. Therefore, the bile acid structure determines the function of the molecule. Many bile acids are similar in …


Using Ion Mobility Mass Spectrometry In Conjuction With Derivatization Methods To Enhance The Separation Of Different Steroid Isomers, Shadrack Lucas May 2024

Using Ion Mobility Mass Spectrometry In Conjuction With Derivatization Methods To Enhance The Separation Of Different Steroid Isomers, Shadrack Lucas

All Theses

One of the major problems facing analytical chemistry challenge is the isomers separation, due to their closely related molecular structures and physicochemical properties. Therefore, in this thesis, we have performed the separation of steroid isomers through the use of ion mobility mass spectrometry, using various chemical approaches. Ion mobility is an effective high-resolution separation techniques that utilizes the mobility of ions in the gas-phase environment. A useful tool for isomeric analysis due to the ability to separate different isomeric classes of steroids according to their varied collision cross-sections, which is achieved by taking advantage of differences in ion mobility.

Moreover, …


Electrosprayed Serine Octamer Magic Number Cluster: Formation Via Gas Phase Assembly And Collision-Induced Dissociation, Vida Alinezhad Apr 2024

Electrosprayed Serine Octamer Magic Number Cluster: Formation Via Gas Phase Assembly And Collision-Induced Dissociation, Vida Alinezhad

Electronic Thesis and Dissertation Repository

Magic number clusters refer to ion species that exhibit unusually high intensities in electrospray ionization (ESI) mass spectrometry (MS) experiments. The serine octamer cluster [Ser8+H]+ is of special interest since its formation mechanism and structure remain controversial, although a recently proposed model in the literature represents a possible candidate structure. Nonetheless, the formation mechanism of [Ser8+H]+ remains unexplored. Some hypotheses suggest that it may pre-exist in bulk solution, or that [Ser8+H]+ can be a collision-induced dissociation (CID) product of large clusters formed in evaporating ESI droplets. We used ESI-MS, mobile proton …


A Multi-Omics Investigation Into The Mechanism Of Action Of An Anti-Tubercular Fatty Acid Analog, Isin T. Sakallioglu, Amith S. Maroli, Aline De Lima Leite, Darrell D. Marshall, Boone W. Evans, Denise K. Zinniel, Patrick H. Dussault, Raul G. Barletta, Robert Powers Mar 2024

A Multi-Omics Investigation Into The Mechanism Of Action Of An Anti-Tubercular Fatty Acid Analog, Isin T. Sakallioglu, Amith S. Maroli, Aline De Lima Leite, Darrell D. Marshall, Boone W. Evans, Denise K. Zinniel, Patrick H. Dussault, Raul G. Barletta, Robert Powers

Patrick Dussault Publications

The mechanism of action (MoA) of a clickable fatty acid analogue 8-(2-Cyclobuten-1-yl)octanoic acid (DA-CB) has been investigated for the first time. Proteomics, metabolomics, and lipidomics were combined with a network analysis to investigate the MoA of DA-CB against Mycobacterium smegmatis (Msm). The metabolomics results showed that DA-CB has a general MoA related to that of ethionamide, a mycolic acid inhibitor that targets enoyl-ACP reductase (InhA), but DA-CB likely inhibits a step downstream from InhA. Our combined multi-omics approach showed that DA-CB appears to disrupt the pathway leading to the biosynthesis of mycolic acids, an essential mycobacterial fatty acid …


Development Of Vacuum-Assisted Headspace High-Capacity Solid-Phase Microextraction For The Determination Of Semi-Volatile Compounds From Samples At Lower Temperatures, Shannon L. Thomas, Kevin A. Schug, Colton Myers, Jason S. Herrington, Reagan L. Miller, Anush Pabley, Frank W. Foss Jan 2024

Development Of Vacuum-Assisted Headspace High-Capacity Solid-Phase Microextraction For The Determination Of Semi-Volatile Compounds From Samples At Lower Temperatures, Shannon L. Thomas, Kevin A. Schug, Colton Myers, Jason S. Herrington, Reagan L. Miller, Anush Pabley, Frank W. Foss

Chemistry & Biochemistry Dissertations

Vacuum-assisted headspace solid-phase microextraction (Vac-HS-SPME) is a method used to increase solid-phase microextraction sampling of semi-volatile organic compounds. Three studies were conducted using Vac-HS-SPME via gas chromatography - mass spectrometry (GC-MS) methods for analysis of various sample types. First, a study was performed using Vac- HS-SPME combined with a high-capacity (HC) SPME Arrow to determine the operational fundamentals and workflow necessary to achieve optimal extraction of semi-volatile compounds from a model solid matrix (Ottawa sand). The fundamentals investigated included the seals necessary to create a leak-free sampling vial under vacuum conditions; the magnitude of the vacuum exerted, and the time …


Development Of Novel Protein Digestion And Quantitation Methods For Mass Spectrometic Analysis, Yongling Ai Dec 2023

Development Of Novel Protein Digestion And Quantitation Methods For Mass Spectrometic Analysis, Yongling Ai

Dissertations

Proteins are the workhorses of biology, playing multifaceted roles in maintaining cellular function, signaling, and response to environmental cues. Understanding their abundance and dynamics is pivotal for unraveling the complexities of biological processes, which underpins the foundations of molecular and cellular biology. Accurate measurement of protein quantities provides insights into cellular homeostasis, facilitates the discovery of biomarkers, and sheds light on the molecular mechanisms of diseases, bridging the gap between the molecular intricacies of proteins and their functional consequences in health and disease. The evolution of protein quantitation methodologies, from classical colorimetric assays to sophisticated mass spectrometry-based approaches, has expanded …


Research Instrumentation Center (Ric), Ryan Hilger, Purdue University Office Of Research Aug 2023

Research Instrumentation Center (Ric), Ryan Hilger, Purdue University Office Of Research

University Research Core Facility Boilerplate Descriptions

No abstract provided.


Identification Of Acidic Residues In Proteins By Selective Chemical Labeling And Tandem Mass Spectrometry, Fnu Ashima Aug 2023

Identification Of Acidic Residues In Proteins By Selective Chemical Labeling And Tandem Mass Spectrometry, Fnu Ashima

Chemistry & Biochemistry Theses

Proteins play important role in carrying out a wide range of cellular activities. They are subjected to various post-translational modifications (PTMs) by the addition of functional groups such as acetyl, phosphoryl, and methyl which leads to changes in their biological functions, localization, activity, and structure. The growth of MS technology has immensely facilitated the identification of PTMs comprehensively. This dissertation focuses on mapping these changes using covalent labeling techniques by tagging carboxylic acid residues, which undergo various kinds of PTMs. The second chapter focuses on the methods designed for Affinity Purification Mass Spectrometry (AP-MS) chemical cross-linking (CXL) of protein complexes. …


Effects Of Hydrogen/Deuterium Exchange On Protein Stability In Solution And In The Gas Phase, Yousef Haidar, Lars Konermann Jun 2023

Effects Of Hydrogen/Deuterium Exchange On Protein Stability In Solution And In The Gas Phase, Yousef Haidar, Lars Konermann

Chemistry Publications

Mass spectrometry (MS)-based techniques are widely used for probing protein structure and dynamics in solution. H/D exchange (HDX)-MS is one of the most common approaches in this context. HDX is often considered to be a “benign” labeling method, in that it does not perturb protein behavior in solution. However, several studies have reported that D2O pushes unfolding equilibria toward the native state. The origin, and even the existence of this protein stabilization remain controversial. Here we conducted thermal unfolding assays in solution to confirm that deuterated proteins in D2O are more stable, with 2 – 4 …


Enhanced Methods In Forensic Mass Spectrometry For Targeted And Untargeted Drug Analysis, Dina M. Swanson Jun 2023

Enhanced Methods In Forensic Mass Spectrometry For Targeted And Untargeted Drug Analysis, Dina M. Swanson

USF Tampa Graduate Theses and Dissertations

Forensic science has long used mass spectrometry for the analysis of drugsand metabolites. Traditionally, screening methods consisted of color tests or immunoassay and confirmation methods used gas chromatography with mass spectrometry, which was considered the gold standard for identification. In the last several decades, advances in liquid chromatography with mass spectrometry (LCMS) have brought this technology to the forefront of forensic drug identification. Drug identification in forensic drug chemistry and forensic toxicology has become increasingly challenging due to the rapid increase in illicit drug analogs including novel opioids such as fentanyl analogs. Traditional screening methodologies are often unable to identify …


Utilizing Ultra-Performance Chromatography High-Resolution Mass Spectrometry To Investigate Fatty Acid Mediated Antibiotic Tolerance, Brittni Woodall May 2023

Utilizing Ultra-Performance Chromatography High-Resolution Mass Spectrometry To Investigate Fatty Acid Mediated Antibiotic Tolerance, Brittni Woodall

Doctoral Dissertations

The lipid membrane is the first component necessary to sustain life. To maintain homeostasis, segregate cellular machinery, provide protection from the environment, and reproduce, an organism must establish a boundary in which the processes can occur. Throughout the last two decades, research has propelled our knowledge of lipid membranes much beyond original hypotheses. Once thought of to be static and uniform, the understanding of the lipid membrane has evolved to encompass a structure that is responsive, unique, and intricately constructed by the organism itself. By chance or by choice, organisms adapt the lipid membrane according to the environment for which …


Quantitative Analysis Of The Proteomic Selectivity Of Acidic Reductive Alkylation Of Peptides, Connor Jewell May 2023

Quantitative Analysis Of The Proteomic Selectivity Of Acidic Reductive Alkylation Of Peptides, Connor Jewell

Honors Scholar Theses

Proteome quantification is a complicated process which takes on many methods, usually involving peptide derivatization and complex mass spectral analysis. Scores of techniques have been utilized to address issues of incomplete quantification. The implementation of IPTL labeling, or isobaric peptide terminal labeling, is a recent addition to the literature, which exploits the supposedly selective labeling of N-termini of tryptic peptides from the C-termini of lysine residues due to differences in basicity. This method has been shown to improve quantitation by reducing spectral complexity and provide more accurate and reproducible results on peptide abundance. Investigations into the selectivity of terminal derivatization …


Developing Chemo-Proteomics Methods For Tyrosine Conjugation And Studies Of Organometallic Complexes Of Gold., Adway Ouseph Zacharias May 2023

Developing Chemo-Proteomics Methods For Tyrosine Conjugation And Studies Of Organometallic Complexes Of Gold., Adway Ouseph Zacharias

Chemistry & Biochemistry Dissertations

The incredible changes in MS instrumentation since the late 1980s with the advent of electrospray ionization (ESI) and matrix-assisted laser desorption/ionization (MALDI) has revolutionized protein chemistry. Mass spectrometry coupled with chemical crosslinking is a powerful tool to decipher protein structure and protein-protein interactions. A majority of commercially available crosslinkers target only few amino acid residues such as lysine, arginine and cysteine, thereby limiting the utility of this technology. The prospect of using chemical reagents to target amino acids is challenging since covalent labeling experiments are performed under physiological aqueous conditions that may be detrimental to the stability of these reagents. …


Epimeric Peptides In Alzheimer’S Disease: Implications For Liquid Chromatography-Mass Spectrometry And Immunotherapies, Elizabeth Readel May 2023

Epimeric Peptides In Alzheimer’S Disease: Implications For Liquid Chromatography-Mass Spectrometry And Immunotherapies, Elizabeth Readel

Chemistry & Biochemistry Dissertations

Evidence has shown that the extracellular deposition of amyloid-beta (Aβ) peptide is a contributing factor of Alzheimer’s disease. Further, modifications to Aβ peptides may enhance the deposition of Aβ plaques and/or contribute to the neurodegeneration in AD patients. These aberrations include the isomerization and epimerization of L-Asp and D-Ser residues to form D-Asp, L/D-iso-Asp, and D-Ser residues, respectively. Therefore, considerable effort has been expended to create effective methods to distinguish such aberrant Aβ peptides from wild type. A useful technique to extract aberrant Aβ peptides in AD patients is by immunotherapies, or antibodies. A few immunotherapies are thought to provide …


Development And Validation Of A Liquid Chromatography-Tandem Mass Spectrometry Method For The Determination Of Temozolomide In Mouse Brain Tissue, Raghavi Kakarla, Kimberly Yacoub, Rebecca L. Bearden, Aimin Zhou, Sanjib Mukherjee, Frank Y. Shan, Baochuan Guo Apr 2023

Development And Validation Of A Liquid Chromatography-Tandem Mass Spectrometry Method For The Determination Of Temozolomide In Mouse Brain Tissue, Raghavi Kakarla, Kimberly Yacoub, Rebecca L. Bearden, Aimin Zhou, Sanjib Mukherjee, Frank Y. Shan, Baochuan Guo

Chemistry Faculty Publications

Temozolomide is a Food and Drug Administration-approved anticancer drug that has poor drug delivery via oral or intravenous routes. A potential strategy to combat this problem is investigating alternative routes of administration, requiring quantitation of the drug in the brain tissues by liquid chromatography-mass spectrometry. However, current methods used to extract the drug from brain tissues resulted in poor recovery and substantial matrix effects. Herein, we reported a new two-step extraction method that involves the use of Proteinase K to lyse tumor tissues to efficiently release the drug, followed by ethanol protein precipitation. The extracts were then separated on a …


Investigating The Dynamics And Fragmentation Of Nitroaromatic Radical Cations Through Femtosecond Time-Resolved Mass Spectrometry And Computational Chemistry, Hugo Andres Lopez Pena Jan 2023

Investigating The Dynamics And Fragmentation Of Nitroaromatic Radical Cations Through Femtosecond Time-Resolved Mass Spectrometry And Computational Chemistry, Hugo Andres Lopez Pena

Theses and Dissertations

Chemists have sought to control molecular dissociation with lasers for decades. Effective control of unimolecular dissociation was only achieved with the development of high-intensity ultrashort pulsed lasers and coherent control techniques that operate on timescales faster than vibrational energy redistribution. In view of this, our lab has specialized in the study of polyatomic radical cations using femtosecond time-resolved mass spectrometry (FTRMS). The interest in radical cations stems from the fact that they are highly reactive species that contribute to many physical, chemical, and biological processes. For instance, radical cations participate in shock initiation of detonated energetic materials used as explosives …


Developing Novel Femtosecond Time-Resolved Mass Spectrometry Techniques For Analysis Of Energetic Materials, Shane L. Mcpherson Jan 2023

Developing Novel Femtosecond Time-Resolved Mass Spectrometry Techniques For Analysis Of Energetic Materials, Shane L. Mcpherson

Theses and Dissertations

Energetic materials and the unimolecular dissociation dynamics attributed to their initiation and subsequent bimolecular detonation have been a subject of interest for defense agencies such as the Department of Defense (DoD) for decades. The timescale in which these initial dynamics exist ranges from several picoseconds to dozens of femtoseconds, necessitating equally fast time-resolved experiments to capture and characterize these events. Our lab specializes in one such laser-based technique: femtosecond time-resolved mass spectrometry (FTRMS). FTRMS is an essentially nondiscriminatory pump-probe laser technique with nearly infinite modifications via pulse shaping, intensity, and wavelength modulation that can readily examine previously undefined dissociation pathways …


Tenvr: Matlab-Based Toolbox For Environmental Research, Aleksandar I. Goranov, Rachel L. Sleighter, Dobromir A. Yordanov, Patrick G. Hatcher Jan 2023

Tenvr: Matlab-Based Toolbox For Environmental Research, Aleksandar I. Goranov, Rachel L. Sleighter, Dobromir A. Yordanov, Patrick G. Hatcher

Chemistry & Biochemistry Faculty Publications

With the advancements in science and technology, datasets become larger and more multivariate, which warrants the need for programming tools for fast data processing and multivariate statistical analysis. Here, the MATLAB-based Toolbox for Environmental Research "TEnvR" (pronounced "ten-ver") is introduced. This novel toolbox includes 44 open-source codes for automated data analysis from a multitude of techniques, such as ultraviolet-visible, fluorescence, and nuclear magnetic resonance spectroscopies, as well as from ultrahigh resolution mass spectrometry. Provided are codes for processing data (e.g., spectral corrections, formula assignment), visualization of figures, calculation of metrics, multivariate statistics, and automated work-up of large datasets. TEnvR allows …


The Influence Of Instrumental Sources Of Variance On Mass Spectral Comparison Algorithms, Isabel Cristina Galvez Valencia Jan 2023

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 …


Application Of Mass Spectrometry For The Characterization Of Synthetic Oligomers And Natural Lignin, Poorya Kamali Jan 2023

Application Of Mass Spectrometry For The Characterization Of Synthetic Oligomers And Natural Lignin, Poorya Kamali

Theses and Dissertations--Chemistry

As part of the ongoing effort to substitute finite fuel and chemical resources with renewable ones, biomass is emerging as one of the most promising sources. Biomass consists of three main components of cellulose, hemicellulose, and lignin. Traditionally, cellulose has been used extensively in pulping industry, while lignin has been considered waste and is burned to generate heat. Lignin, a complex aromatic polymer component of biomass, has the potential to be used as a source of aromatic chemicals and pharmaceutical synthons. The recalcitrant nature of lignin, the lack of effective lignin breakdown methods and analytical techniques to analyze it are …


Investigation Of Early Complex Formation Of Huntingtin Protein With And Without Lipids, Alyssa R. Stonebraker Jan 2023

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 …


Class A Sortases: Structures And Alternative Substrate Binding And Cleavage, Brandon Vogel Jan 2023

Class A Sortases: Structures And Alternative Substrate Binding And Cleavage, Brandon Vogel

WWU Graduate School Collection

Sortases, consisting of classes A-F, are cysteine transpeptidases found in the cell wall of Gram-positive bacteria. They play a crucial role in ligating proteins to the cell wall that are responsible for cell adhesion, immune evasion, host cell invasion, and nutrient acquisition through a transpeptidation reaction. Consequently, they are an attractive therapeutic target. Class A sortases are also utilized in protein engineering applications such as sortase-mediated ligations and sortagging. Despite extensive research in the past two decades, gaps persist in understanding how class A sortases recognize their substrates, primarily due to a lack of structural information on sortases non-covalently bound …


Natural Product Discovery And Mycotoxin Analysis Of Agricultural Endophytes And Pathogens, Jacob P. Walsh Sep 2022

Natural Product Discovery And Mycotoxin Analysis Of Agricultural Endophytes And Pathogens, Jacob P. Walsh

Electronic Thesis and Dissertation Repository

This thesis focuses on the application of fungal natural product chemistry for the use of agriculture fungal pathogenesis research. The research in this work uses many analytical chemistry techniques and instruments such as HPLC, LC-MS/MS and NMR. In Chapter 2, a diagnostic fragmentation module was developed for the identification of compound classes in crude fungal extracts. This module identified the classes cytochalasins and chaetoglobosins from extracts of Penicillium, Chaetomium, and Xylaria. From these extracts a new chaetoglobosin was discovered and the module was implemented into the open-source software package MZmine 2.0. Chapter 3 discusses analytical chemistry techniques with the …


Polyphenols And Small Phenolic Acids As Cellular Metabolic Regulators, Mark Obrenovich, Yi Li, Moncef Tayahi, V. Prakash Reddy Sep 2022

Polyphenols And Small Phenolic Acids As Cellular Metabolic Regulators, Mark Obrenovich, Yi Li, Moncef Tayahi, V. Prakash Reddy

Chemistry Faculty Research & Creative Works

Polyphenols and representative small phenolic acids and molecules derived from larger constituents are dietary antioxidants from fruits, vegetables and largely other plant-based sources that have ability to scavenge free radicals. What is often neglected in polyphenol metabolism is bioavailability and the role of the gut microbiota (GMB), which has an essential role in health and disease and participates in co-metabolism with the host. The composition of the gut microbiota is in constant flux and is modified by multiple intrinsic and extrinsic factors, including antibiotics. Dietary or other factors are key modulators of the host gut milieu. In this review, we …


Meta-Analysis Reveals Both The Promises And The Challenges Of Clinical Metabolomics, Heidi E. Roth, Robert Powers Aug 2022

Meta-Analysis Reveals Both The Promises And The Challenges Of Clinical Metabolomics, Heidi E. Roth, Robert Powers

Chemistry Department: Faculty Publications

Clinical metabolomics is a rapidly expanding field focused on identifying molecular biomarkers to aid in the efficient diagnosis and treatment of human diseases. Variations in study design, metabolomics methodologies, and investigator protocols raise serious concerns about the accuracy and reproducibility of these potential biomarkers. The explosive growth of the field has led to the recent availability of numerous replicate clinical studies, which permits an evaluation of the consistency of biomarkers identified across multiple metabolomics projects. Pancreatic ductal adenocarcinoma (PDAC) is the third-leading cause of cancer-related death and has the lowest five-year survival rate primarily due to the lack of an …


Quantifying Protein Quality To Understand Protein Homeostasis (Supplemental Data), Hsien-Jung Lavender Lin Jul 2022

Quantifying Protein Quality To Understand Protein Homeostasis (Supplemental Data), Hsien-Jung Lavender Lin

ScholarsArchive Data

This data set includes the supplementary data for chpaters 3 and 4 in the dissertation Quantifying Protein Quality to Understand Protein Homeostasis. It includes various excel worksheets that were used to generate the data reported in the dissertation. We make this data available to the public so anyone who wants to reproduce the results has the resources and access to other perspectives that weren't discussed in depth in the dissertation. Chapter 3 used mass-spectrometry to quantify the surface accessibility differences in human serum albumin (HSA)between patients with and without rheumatoid arthritis (RA). We found certain residues are less reactive …


Analysis Of The Zebrafish Olfactory System Using Immunohistochemistry And Enhanced Techniques Of Desorption Electrospray Ionization Mass Spectrometry (Desi-Ms), Tara Lynn Maser Jun 2022

Analysis Of The Zebrafish Olfactory System Using Immunohistochemistry And Enhanced Techniques Of Desorption Electrospray Ionization Mass Spectrometry (Desi-Ms), Tara Lynn Maser

Dissertations

Desorption electrospray ionization (DESI-MS) is an ambient ionization technique where the sample is analyzed directly from a surface with very minimal sample preparation under ambient conditions and follows ESI-like ionization mechanisms. DESI-MS has proven powerful in analyzing or imaging lipids and other small molecules directly from biological samples and even allows for subsequent histological staining and analyses. However, DESI-MS is less widely used for protein analysis due to a lack of sensitivity and the complex diversity of proteins in biological samples.

A major goal of this research has been to obtain new neurobiological knowledge by combining histology and mass spectrometry …


Crude Oil Characterization Using Gas Chromatography, Ion Mobility Spectrometry And Mass Spectrometry, Clement A. Olanrewaju Jun 2022

Crude Oil Characterization Using Gas Chromatography, Ion Mobility Spectrometry And Mass Spectrometry, Clement A. Olanrewaju

FIU Electronic Theses and Dissertations

The characterization of crude oils at the compositional level remains challenging due to their high chemical complexity and isomeric diversity. The present work expands the analytical separation space of chemical components in crude oils by coupling gas chromatography (GC), trapped ion mobility spectrometry (TIMS), and mass spectrometry (GC-TIMS-MS and TIMS-FT-ICR MS) for the effective separation and identification of isomeric compounds. The coupling of GC and TIMS-MS platform enhanced the peak capacity and showed complementary isomeric separation. The combination of GC-TIMS-MS and GC-EI-MS technique provided a comprehensive characterization of PAHs and similar compounds from crude oils on the basis of retention …


Atmospheric Mercury Chemistry: Detection, Kinetics, And Mechanism, Na Mao May 2022

Atmospheric Mercury Chemistry: Detection, Kinetics, And Mechanism, Na Mao

Dissertations

The presence of mercury in the environment is of global concern due to its toxicity. The atmosphere is an important transient reservoir for mercury released by human activities and natural sources. The knowledge of atmospheric mercury chemistry is critical for understanding the global biogeochemical cycle. In the atmosphere, mercury primarily exists in three forms: gaseous elemental mercury (GEM), gaseous oxidized mercury (GOM), and particulate-bound mercury (PBM). Over the last decade, the existing knowledge of mercury cycle has dramatically changed: (1) There has been increasing evidence that current detection methods do not accurately quantify gaseous oxidized mercury and a technique which …