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Toward Improved Characterization Of Biologically Relevant Isomeric And Isobaric Ions On Mass Spectrometry-Based Platforms, Baku Acharya
Toward Improved Characterization Of Biologically Relevant Isomeric And Isobaric Ions On Mass Spectrometry-Based Platforms, Baku Acharya
Theses and Dissertations
Mass spectrometry has frequently been employed in the analysis of biologically relevant molecules; however, mass spectrometry alone may not always be sufficient for the differentiation and characterization of isomeric and isobaric ions. In this work, infrared multiple photon dissociation (IRMPD) spectroscopy and ion mobility spectrometry (IMS) were evaluated as complementary techniques for the characterization and separation of isomeric and isobaric ions of biological relevance. In the first project, analysis of experimental IRMPD spectroscopy data shows that this technique is useful in the differentiation of hydroxyproline isomers. Absorption bands allow for the differentiation of three isomeric species: 1640 cm-1 (trans-4-hydroxyproline), 1718 …
Investigation Of The Reactivity Of The Cytosine-5-Yl Radical Ion Using Ion Trap Mass Spectrometry, Tassiani Sarretto
Investigation Of The Reactivity Of The Cytosine-5-Yl Radical Ion Using Ion Trap Mass Spectrometry, Tassiani Sarretto
University of Wollongong Thesis Collection 2017+
Nucleobases play a significant biological role in DNA and RNA. Since the discovery that halogenated pyrimidines act as a good sensitizer for radiotherapy, the attention on 5-halouracil has increased, however the photoreactivity of cytosine and its derivatives has not been investigated. This study presents, for the first time, the highly selective generation of the cytosine-5-yl radical ion obtained by photodissociation of halogenated precursors. Using a modified linear ion trap mass spectrometer, gas-phase reactions and product channels are presented and mechanisms of possible pathways of photodissociation are discussed for reactions between the radical ion with molecular oxygen and unsaturated hydrocarbons including, …
Reactions Of Dehydro-N-Pyridinium With Small Unsaturated Hydrocarbons, Cameron C. Bright
Reactions Of Dehydro-N-Pyridinium With Small Unsaturated Hydrocarbons, Cameron C. Bright
University of Wollongong Thesis Collection 2017+
Small nitrogen containing heteroaromatics are fundamental building blocks for many biological molecules, including the DNA nucleotides. Pyridine, as a prototypical Nheteroaromatic, has been implicated in the chemical evolution of many extraterrestrial environments, including the atmosphere of Titan. This thesis describes reactions of the three dehydro-N-pyridinium radical cation isomers with a set of small, unsaturated hydrocarbons: propene, acetylene, ethene and propyne. These reactions were chosen due to their possible involvement in molecular-weight growth processes, and in the synthesis of complex organics in space. Mass spectrometric techniques are used to acquire product mass spectra, measure product branching ratios and calculate second-order rate …
Synthesis, Characterization, And Rna Reactivity Of Amino-Acid-Linked Cisplatin Analogues, Xun Bao
Synthesis, Characterization, And Rna Reactivity Of Amino-Acid-Linked Cisplatin Analogues, Xun Bao
Wayne State University Dissertations
The essential role of ribosomal RNA (rRNA) in the cell life cycle is highlighted by protein synthesis; therefore, the ribosome is considered to be an ideal drug target. Ribosomal RNAs exhibit a high level of structural diversity. The well-known anticancer drug cisplatin was previously applied as a chemical probe of rRNA structure to determine solvent accessible purines (guanosine) in vivo and in vitro. Cisplatin accumulates faster on RNA than DNA, with less chance of repair. As such, designing new RNA-targeting Pt compounds is not only a promising direction for chemical-probing applications, but also for the design of anticancer drugs that …
Anthropogenic Osmium In Rain And Snow Reveals Global-Scale Atmospheric Contamination, Cynthia Chen, Peter N. Sedwick, Mukul Sharma
Anthropogenic Osmium In Rain And Snow Reveals Global-Scale Atmospheric Contamination, Cynthia Chen, Peter N. Sedwick, Mukul Sharma
Dartmouth Scholarship
Osmium is one of the rarer elements in seawater, with typical concentration of approximately 10 x 10(-15) g g(-1) (5.3 x 10(-14) mol kg(-1)). The osmium isotope composition ((187)Os/(188)Os ratio) of deep oceans is 1.05, reflecting a balance between inputs from continental crust (approximately 1.3) and mantle/cosmic dust (approximately 0.13). Here, we show that the (187)Os/(188)Os ratios measured in rain and snow collected around the world range from 0.16 to 0.48, much lower than expected (>1), but similar to the isotope composition of ores (approximately 0.2) that are processed to extract platinum and other metals to be used primarily …
Anthropogenic Osmium In Rain And Snow Reveals Global-Scale Atmospheric Contamination, Cynthia Chen, Peter N. Sedwick, Mukul Sharma
Anthropogenic Osmium In Rain And Snow Reveals Global-Scale Atmospheric Contamination, Cynthia Chen, Peter N. Sedwick, Mukul Sharma
OES Faculty Publications
Osmium is one of the rarer elements in seawater, with typical concentration of ≈10 x 10-15 g g-1 ( 5.3 x 10-14 mol kg-1. The osmium isotope composition (187Os/188Os ratio) of deep oceans is 1.05, reflecting a balance between inputs from continental crust (≈ 1.3) and mantle/cosmic dust (≈ 0.13). Here, we show that the 187Os/188Os ratios measured in rain and snow collected around the world range from 0.16 to 0.48, much lower than expected (>1), but similar to the isotope composition of ores (approximate to 0.2) …
Development Of Novel Liquid Chromatography-Electrospray Tandem Mass Spectrometry Approaches For The Structural Characterization Of Brevetoxins Including In Vitro Metabolites, Weiqun Wang
University of New Orleans Theses and Dissertations
Brevetoxins are natural neurotoxins that are produced by “red tide†algae. In this study, brevetoxin-1 and brevetoxin-2 were incubated with rat liver hepatocytes and rat liver microsomes, respectively. After clean-up steps, samples were analyzed by liquid chromatography-electrospray mass spectrometry (LC-ES-MS). Two metabolites were found for brevetoxin-1: brevetoxin-1-M1 (MW 900 Da), formed by converting one double bond in the E or F ring into a diol; and brevetoxin-1-M2 (MW 884 Da), a hydrolysis product of brevetoxin-1 involving opening of the lactone ring. The incubation study of brevetoxin-2 found two metabolites. Brevetoxin-2-M1 (MW 912 Da) was elucidated by negative mode LC-MS/MS to …