Organic Chemistry Commons^™

Developing A Method To Identify Tyre Particles By Detecting Benzothiazole Via Gc-Ms, Emma Paull

The Plymouth Student Scientist

Tyre particles are a dominant source of microplastic pollution in our environment. However, their chemical and physical properties are poorly understood and no standardised methods for identifying and quantifying them exist. This study looked to develop a method to identify tyre particles using two tyre samples of differing particle sizes, fine (62 - 125 µm) and coarse (250 – 500 µm). Both samples underwent ultrasound-assisted extraction before being analysed via gas chromatography-mass spectrometry (GC-MS) in both full scan and SIM mode, using benzothiazole as a marker. Both samples were also analysed via particle size analysis, scanning electron microscopy (SEM) and …

Activation Of The Renin–Angiotensin–Aldosterone System Is Attenuated In Hypertensive Compared With Normotensive Pregnancy, Robin C. Shoemaker, Marko Poglitsch, Hong Huang, Katherine Vignes, Aarthi Srinivasan, Cynthia Cockerham-Morris, Aric Schadler, John Anthony Bauer, John O'Brien

UK CARES Faculty Publications

Hypertension during pregnancy increases the risk of adverse maternal and fetal outcomes, but the mechanisms of pregnancy hypertension are not precisely understood. Elevated plasma renin activity and aldosterone concentrations play an important role in the normal physiologic adaptation to pregnancy. These effectors are reduced in patients with pregnancy hypertension, creating an opportunity to define the features of the renin–angiotensin–aldosterone system (RAAS) that are characteristic of this disorder. In the current study, we used a novel LC-MS/MS-based methodology to develop comprehensive profiles of RAAS peptides and effectors over gestation in a cohort of 74 pregnant women followed prospectively for the development …

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 The Analytical Utility Of The Inductively Coupled Plasma Mass Spectrometer (Icp-Ms) For The Quantification Of Proteins Via Lanthanide Labeling, Caitlin Elizabeth Dunlap

Undergraduate Honors Thesis Collection

The discovery and ability to provide an absolute concentration of biomarkers in the body can facilitate early diagnoses of diseases. This information can also be used for more accurate and unique treatments for those patients. While major advances in molecular mass spectrometry allows for a sensitive identification of these biomarkers, they are limited to only four orders of magnitude in their dynamic ranges. Due to this, detection and quantitation of low abundant proteins, which tend to make up these vital biomarkers, is very difficult. On the other hand, ICP-MS offers a wider dynamic range (up to 12 orders of magnitude) …

Microbial Labilization And Diversification Of Pyrogenic Dissolved Organic Matter, Aleksandar I. Goranov, Andrew S. Wozniak, Kyle W. Bostick, Andrew R. Zimmerman, Siddhartha Mitra, Patrick G. Hatcher

Chemistry & Biochemistry Faculty Publications

With the increased occurrence of wildfires around the world, interest in the chemistry of pyrogenic organic matter (pyOM) and its fate in the environment has increased. Upon leaching from soils by rain events, significant amounts of dissolved pyOM (pyDOM) enter the aquatic environment and interact with microbial communities that are essential for cycling organic matter within the different biogeochemical cycles. To evaluate the biodegradability of pyDOM, aqueous extracts of laboratory-produced biochars were incubated with soil microbes, and the molecular changes to the composition of pyDOM were probed using ultrahigh-resolution mass spectrometry (Fourier transform–ion cyclotron resonance–mass spectrometry). Given that solar irradiation …

Marcadores Moleculares Subrogados A La Repelencia Al Agua En Suelos Afectados Por El Fuego, Nicasio T. Jiménez-Morillo, Gonzalo Almendros, Nuno Guiomar, Ana Z. Miller, Cristina Barrocas-Dias, José M. De La Rosa, Patrick G. Hatcher, José A. González-Pérez

Chemistry & Biochemistry Faculty Publications

Soil water repellency (SWR) is often attributed to the accumulation of hydrophobic organic compounds, mainly lipids. Nonetheless, lipid extraction not always suppress SWR and unextractable soil constituents may be related with residual SWR. Burnt (B) and unburnt (UB) soils (Doñana National Park, Huelva) under two vegetations (cork oak and heather) and two soil fractions, coarse (1–2 mm) and fine (

Mechanisms And Applications Of Improved Protein Analysis By Desorption Electrospray Ionization Mass Spectrometry (Desi-Ms), Roshan Javanshad

Dissertations

Electrospray ionization mass spectrometry (ESI-MS) is a soft ionization technique that allows detection of macromolecules, such as intact proteins, by the formation of multiply charged ions from solutions. Desorption electrospray ionization mass spectrometry (DESI-MS) is an ambient ionization technique that directly samples analyte from a surface during ESI-MS analysis. Although DESI-MS is highly accomplished at the analyses of metabolites, lipids, and other small molecules, it is far more limited when it comes to protein analysis. While most of the field in ambient ionization MS has moved towards primarily applications, our approach has been to explore the use of DESI-MS and …

Don't Sell Them Short, There's More To Bacterial Natural Products Than Antibiotics, Alison Clare Domzalski

Dissertations, Theses, and Capstone Projects

Recent genomic studies of microbiomes have revealed an overwhelming number of biosynthetic genes of unknown function. Most of these “cryptic” biosynthetic genes are not expressed in laboratory monocultures of individual microbes. Thus, there remains tremendous untapped potential for natural products discovery. Here we employ mixed microbial culture (MMC) as a simple yet powerful approach to awaken cryptic biosynthetic gene clusters. Our preliminary studies demonstrated that arrays of metabolites could be induced in MMCs upon environmental cues, such as surface adhesion. Using this system, we have screened, identified, and isolated bioactive bacterial metabolites, which were characterized structurally and biologically. Of the …

Records Of Enriched Uranium Atmospheric Deposition In Pond Sediments In Piketon, Oh, Brianna Herner, Brian Majestic, Michael Ketterer

DU Undergraduate Research Journal Archive

The enrichment of uranium, often for nuclear weapons programs and commercial nuclear reactors, produces higher concentrations of radioactive uranium 235 (²³⁵U) than what naturally occurs, which can pose a human health hazard. The most abundant naturally occurring uranium isotope is ²³⁸U, which is still radioactive, however a higher concentration of ²³⁵U skews the observed isotopic uranium distribution. The Department of Energy Portsmouth Gaseous Diffusion Plant, located near Piketon, OH, enriched uranium from 1954 to 2001 and ²³⁵U pollution has recently been detected in air and sediment samples in the surrounding community. The extent of the …

Labilization And Diversification Of Pyrogenic Dissolved Organic Matter By Microbes, Aleksandar I. Goranov, Andrew S. Wozniak, Kyle W. Bostick, Andrew R. Zimmerman, Siddhartha Mitra, Patrick G. Hatcher

Chemistry & Biochemistry Faculty Publications

With the increased occurrence of forest fires around the world, interest in the chemistry of pyrogenic organic matter (pyOM) and its fate in the environment has increased. Upon leaching from soils by rain events, significant amounts of dissolved pyOM (pyDOM) enter the aquatic environment and interact with microbial communities that are essential for cycling organic matter within the different biogeochemical cycles. To evaluate the bio-reactivity of pyDOM, aqueous extracts of laboratory-produced chars were incubated with soil microbes and the molecular changes to the composition of pyDOM were probed using ultrahigh resolution mass spectrometry (Fourier transform – ion cyclotron resonance – …

Reactivity Of Ketyl And Acetyl Radicals From Direct Solar Actinic Photolysis Of Aqueous Pyruvic Acid, Alexis J. Eugene, Marcelo I. Guzman

Chemistry Faculty Publications

The variable composition of secondary organic aerosols (SOA) contributes to the large uncertainty for predicting radiative forcing. A better understanding of the reaction mechanisms leading to aerosol formation such as for the photochemical reaction of aqueous pyruvic acid (PA) at λ ≥ 305 nm can contribute to constrain these uncertainties. Herein, the photochemistry of aqueous PA (5-300 mM) continuously sparged with air is re-examined in the laboratory under comparable irradiance at 38° N at noon on a summer day. Several analytical methods are employed to monitor the time series of the reaction, including (1) the derivatization of carbonyl (C═O) functional …

Metabolic Investigations Of The Molecular Mechanisms Associated With Parkinson’S Disease, Robert Powers, Shulei Lei, Annadurai Anandhan, Darrell D. Marshall, Bradley Worley, Ronald Cerny, Eric D. Dodds, Yuting Huang, Mihalis I. Panayiotidis, Aglaia Pappa, Rodrigo Franco

Robert Powers Publications

Parkinson’s disease (PD) is a neurodegenerative disorder characterized by fibrillar cytoplasmic aggregates of α-synuclein (i.e., Lewy bodies) and the associated loss of dopaminergic cells in the substantia nigra. Mutations in genes such as α -synuclein (SNCA) account for only 10% of PD occurrences. Exposure to environmental toxicants including pesticides and metals (e.g., paraquat (PQ) and manganese (Mn)) is also recognized as an important PD risk factor. Thus, aging, genetic alterations, and environmental factors all contribute to the etiology of PD. In fact, both genetic and environmental factors are thought to interact in the promotion of idiopathic PD, but the mechanisms …

Application Of Electrospray Ionization Mass Spectrometry For Ionic Liquids And Their Biodegradation Products, Sepideh Rahbarirad

Masters Theses

Ionic liquids (ILs) are organic salts with unique physico-chemical properties and are used as green alternatives to volatile organic solvents. ESI-MS is a sensitive technique to detect these stable, permanent ions. My research focused on (1) Identification of biodegradation products of ionic liquids and (2) Multiplexed tandem MS by modulation of ionization efficiency.

Studies, have demonstrated that ILs are toxic to the environment, which makes their biodegradability an important consideration. In this work, metabolites generated during the biodegradation of 1-butyl-3-methylimidazolium chloride (BMIM), a degradation resistant and commonly used ionic liquid, are identified using high performance liquid chromatography-mass spectrometry (LC-MS).

Multiplexed …

Enzyme, Cosolvent, And Substrate Interactions In Ple Hydrolysis Reactions And Evaluation Of The Stability Of An Unnatural Glutathione Analogue, Maureen Elizabeth Smith

Dissertations

Prochiral diester malonates have been hydrolyzed in the presence of Pig Liver Esterase (PLE). Several of the diesters produced the respective half-ester in moderate to high enantioselectivity. A series of cosolvent assays were performed to evaluate the ability of the cosolvent to influence the enantioselective outcome of the hydrolysis reactions. Ethanol produced the largest changes in enantioselectivity of all solvents evaluated. The isoenzymes of PLE were also evaluated and provided very different enantioselective outcomes than that of crude PLE. A series of NMR titrations was performed to explore the interactions between the substrates and ethanol cosolvents.

Improvements to our previously …

Fundamental Studies Of Protein Ionization For Improved Analysis By Electrospray Ionization Mass Spectrometry And Related Methods, Kevin A. Douglass

Dissertations

Mass spectrometry (MS) is an analytical technique in which a sample is converted to gas-phase ions that are subsequently separated and detected. It offers great speed, selectivity, and sensitivity during analysis, characteristics which have enabled it to become a leading method for the study of proteins. The applications of MS for these biologically significant macromolecules range from accurately determining identity and sequence to shedding light on post-translational modifications and protein-molecule interactions. As a first step towards analysis by MS, gas-phase protein ions must be formed. A common method for ionization is electrospray ionization (ESI), where a liquid sample including the …

A Novel Algorithm For Validating Peptide Identification From A Shotgun Proteomics Search Engine, Ling Jian, Xinnan Niu, Zhonghang Xia, Parimal Samir, Chiranthani Sumanasekera, Zheng Mu, Jennifer L. Jennings, Kristen L. Hoek, Tara Allos, Leigh M. Howard, Kathryn M. Edwards, P. Anthony Weil, Andrew J. Link

Chemistry Faculty Research

Liquid chromatography coupled with tandem mass spectrometry (LC–MS/MS) has revolutionized the proteomics analysis of complexes, cells, and tissues. In a typical proteomic analysis, the tandem mass spectra from a LC–MS/MS experiment are assigned to a peptide by a search engine that compares the experimental MS/MS peptide data to theoretical peptide sequences in a protein database. The peptide spectra matches are then used to infer a list of identified proteins in the original sample. However, the search engines often fail to distinguish between correct and incorrect peptides assignments. In this study, we designed and implemented a novel algorithm called De-Noise to …

New Applications Of Mass Spectrometry For Drug And Lipid Analysis, Elizabeth Lauren Emerson

Graduate Theses and Dissertations

Mass spectrometry is an important tool used in many different disciplines and settings that include forensics, drug discovery, environmental analysis, and proteomics. Gas chromatography - mass spectrometry (GC-MS) and matrix assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI - TOF MS) are two of the most important instruments used for analysis of compounds. Chapters 1 and 2 of this discussion use GC-MS for the investigation of synthetic cannabinoids in `K2' incense products and the detection of metabolites in urine samples from individuals suspected of consuming these mixtures. Analytical standards were synthesized and used for identification and confirmation of structures. Detection of …