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Full-Text Articles in Physical Sciences and Mathematics
Reinterpreting The Tectonic Model Of The Southern Part Of The Taconic Orogeny Through A Provenance Study Of Late Ordovician Sandstones, Juan Carlos Guerrero
Reinterpreting The Tectonic Model Of The Southern Part Of The Taconic Orogeny Through A Provenance Study Of Late Ordovician Sandstones, Juan Carlos Guerrero
LSU Master's Theses
A provenance study of quartz arenites that stratigraphically are closely associated with major Ordovician K-bentonites has been conducted in order to further our understanding of the tectonic setting of eastern Laurentia during the Late Ordovician. Using laser ablation ICP-MS, detrital zircons separated from Ordovician sandstone samples in the southeastern Appalachian Mountains (Virginia to Alabama) were dated using U-Pb geochronology. Analytical results show three dominate age ranges for the zircons from these sandstones: ~440-490 Ma, ~900-1300 Ma, and ~1300-1500 Ma. In addition, some zircon ages grouped into older ranges of ~1600-1800 Ma, ~1800-1900 Ma, and ~2600-2800 Ma. Zircon ages from ~900-2800 …
Analysis Of Veterinary Drug Residues In Imported And Domestic Crawfish Using Liquid Chromatography—Mass Spectrometry, Emily Kate Wall
Analysis Of Veterinary Drug Residues In Imported And Domestic Crawfish Using Liquid Chromatography—Mass Spectrometry, Emily Kate Wall
LSU Master's Theses
Aquaculture production has greatly increased over the past few decades, and will continue to grow as the world fisheries become overfished and demand for seafood increases. With increased production comes more intense cultivation methods and heavy use of formulated feeds that may contain veterinary drug residues. Currently no antibiotics are allowed in the U.S. for crawfish aquaculture; yet, detectable levels of various antibiotics have been found in imported seafood samples.The FDA is responsible for testing aquaculture products entering the United States, but only has the capabilities to test a minimal amount of those imports. Additionally, for crawfish there is only …
Particle Formation In Ambient Mass Spectrometry, Thabiso Musapelo
Particle Formation In Ambient Mass Spectrometry, Thabiso Musapelo
LSU Doctoral Dissertations
A particle sizing system was developed that couples a light scattering particle sizer with a differential mobility analyzer for particle detection and elucidation with the capability for measuring particle sizes in the range of 10 nm to 20 μm. The particle sizing system was used to investigate particle formation that is associated with several methods of atmospheric pressure ion formation used in mass spectrometry: atmospheric pressure matrix-assisted laser desorption ionization (MALDI) and inlet ionization. The methods for particle formation were 1) ultraviolet (UV) laser ablation, 2) infrared (IR) laser ablation, and 3) shock-generated particle formation. Particles formed by UV laser …
Detection Of Microorganisms Using Maldi And Ion Mobility Mass Spectrometry, Juaneka Monet Hayes
Detection Of Microorganisms Using Maldi And Ion Mobility Mass Spectrometry, Juaneka Monet Hayes
LSU Doctoral Dissertations
Matrix-assisted laser ablation desorption ionization MALDI and ion mobility (IM) MALDI mass spectrometry (MS) were used for the detection and identification of microorganisms. MALDI MS is an analytical tool that separates ions by their mass-to-charge ratio (m/z) and is routinely used for bioanalysis because of its sensitivity, selectivity, general applicability, and tolerance to impurities. Ion mobility is a gas phase technique that separates ions based on their charge and collision cross-section. In this research, MALDI-TOF MS and MALDI-IM-TOF MS analysis were conducted in parallel to assess the effectiveness of MALDI-IM-TOF MS for microorganism identification. Whole cell bacteria Escherichia coli strain …
Laser Ablation Sample Transfer For Mass Spectrometry, Sung-Gun Park
Laser Ablation Sample Transfer For Mass Spectrometry, Sung-Gun Park
LSU Doctoral Dissertations
In this research, a new ambient sampling technique for mass spectrometry was developed that uses an infrared laser to ablate materials under ambient conditions that are captured in a solvent or on a surface. An infrared optical parametric oscillator (OPO) laser system at 3 μm wavelength was focused onto samples for ablation at atmospheric pressure. The ablated materials were transferred to a solvent or surface. For off-line electrospray ionization (ESI) and matrix-assisted laser desorption/ionization (MALDI) analysis, the ablated material was captured in a static solvent droplet that was deposited on a MALDI target or flow-injected into a nanoelectrospray source. The …
Infrared Laser Ablation For Biological Mass Spectrometry, Fan Huang
Infrared Laser Ablation For Biological Mass Spectrometry, Fan Huang
LSU Doctoral Dissertations
Instrument and technique development and modeling of ionization methods using infrared (IR) laser desorption and ablation for mass spectrometry (MS) analysis of chemical and biochemical samples are described. Infrared lasers are highly efficient at sample removal and post-ablation ionization of materials removed by IR laser can be used to improve ionization efficiency. Fundamental studies of the physical processes in laser ablation mass spectrometry can help elucidate the mechanism. In this research, an infrared/ultraviolet two-laser matrix-assisted laser desorption ionization (MALDI) MS was developed for analysis of biomolecules. An infrared laser was used to ablate a mixture of analyte and matrix, and …
Proteomic Analysis Of The Blood Of Alligator Mississippiensis, Lancia Nadinia Fallen Darville-Bowleg
Proteomic Analysis Of The Blood Of Alligator Mississippiensis, Lancia Nadinia Fallen Darville-Bowleg
LSU Doctoral Dissertations
My research focus was to investigate alligator blood using mass spectrometry-based proteomics methods to understand their innate immune systems. The first goal was to sequence peptides and proteins from the blood serum and leukocytes using tandem mass spectrometry and de novo sequencing. The second goal was to determine the function of these biological molecules and their relationship to the immune system. One- and two-dimensional gel electrophoresis was used to separate proteins from alligator leukocytes, which were enzymatically digested. The peptides were measured using reversed phase nano-high performance liquid chromatography coupled with tandem mass spectrometry (nano-HPLC-MS/MS) followed with de novo sequencing. …
Microfluidic Devices Interfaced To Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry For Proteomics, Jeonghoon Lee
Microfluidic Devices Interfaced To Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry For Proteomics, Jeonghoon Lee
LSU Doctoral Dissertations
Microfluidic interfaces were developed for off-line matrix-assisted laser desorption/ionization mass spectrometry (MALDI). Microfluidic interfaces allow samples to be manipulated on-chip and deposited onto a MALDI target plate for analysis. For this research, microfluidic culturing devices and automated digestion and deposition microfluidic chip platforms were developed for the identification of proteins. The microfluidic chip components were fabricated on a poly(methyl methacrylate), PMMA, wafer using the hot embossing method and a molding tool with structures prepared via micromilling. One of the most important components of the chip system was a trypsin microreactor. An open channel microreactor was constructed in a 100 µm …
Merged Electrospray Ionization Mass Spectrometry, Jianan Dong
Merged Electrospray Ionization Mass Spectrometry, Jianan Dong
LSU Doctoral Dissertations
Ambient ionization allows the analysis of materials in their native environment without sample preparation by creating ions outside the mass spectrometer. The goal of this research was to develop new ambient ionization techniques for application to solids, liquids and particles under ambient conditions. Samples to be analyzed were directly merged with an electrospray of droplets, and then ionized and detected by a mass spectrometer. An ion trap mass spectrometer was modified with a nanoelectrospray source and configured for three experiments: merged electrospray ionization of dry particles, merged electrospray ionization of combustion products, and infrared laser desorption/ablation using electrospray for post-ionization. …
Chemical Differences Of Atherosclerotic Plaques In Native And Bypass Human Coronary Arteries And Diseased And Non-Diseased Human Aortas, Samuel Jean Washington
Chemical Differences Of Atherosclerotic Plaques In Native And Bypass Human Coronary Arteries And Diseased And Non-Diseased Human Aortas, Samuel Jean Washington
LSU Doctoral Dissertations
ABSTRACT Cardiovascular disease, primarily atherosclerosis involves a number of distinct processes that are associated with plaque development. The use of differential gel electrophoresis to determine differences between proteins produced in native and bypass coronary arteries from the same heart has been studied. The analytical techniques presented in this study to characterize plaque samples include two dimensional gel electrophoresis, sodium dodecylsulfate polyacrylamide gel electrophoresis, mass spectrometry, differential gel electrophoresis, and high performance liquid chromatography. An overview of the stages involved in atherosclerosis and the theories implicated in the manifestation of atherosclerosis was presented. A design study using the Box Behnken method …
Infrared Laser Desorption/Ionization Mass Spectrometry: Fundamental And Applications, Mark Little
Infrared Laser Desorption/Ionization Mass Spectrometry: Fundamental And Applications, Mark Little
LSU Doctoral Dissertations
This dissertation on infrared laser desorption/ionization mass spectrometry encompasses fundamental studies of the desorption/ionization process and direct-from-gel laser desorption/ionization applications. Understanding of the fundamentals behind desorption and ionization can lead to improvements in the technique and to new applications. Experiments aimed at advancing this goal are wavelength studies and two-laser infrared/ultraviolet matrix-assisted laser desorption/ionization experiments. The direct-from-gel laser desorption/ionization application in which infrared laser desorption/ionization of analytes directly ionized after gel electrophoretic separation will also be presented. Protein and peptide standards were used as test analytes and the infrared lasers used were a 10.6 micrometers carbon-dioxide laser and a mid-IR …
Integrating Micro-Scale Separations To Matrix Assisted Laser Desorption And Ioniation Time Of Flight Mass Spectrometry (Maldi-Tof-Ms) For Protein Analysis, Harrison K. Musyimi
Integrating Micro-Scale Separations To Matrix Assisted Laser Desorption And Ioniation Time Of Flight Mass Spectrometry (Maldi-Tof-Ms) For Protein Analysis, Harrison K. Musyimi
LSU Doctoral Dissertations
This dissertation describes the integration of micro-scale separations to matrix assisted laser desorption and ionization time-of-flight mass spectrometry (MALDI TOF MS) for protein analysis. MALDI MS provides unsurpassed accurate mass measurements of intact bio-molecules, for example peptides and proteins, which in turn generate high molecular specificity enabling the identity, function and structure of these molecules to be characterized. However, in order to realize the full potential of MS in proteomic studies, integrated sample processing on automated and high throughput platforms is required to address the complexity, diversity and the dynamic range of proteomic analysis. The work described here contributes towards …
The Synthesis Of Deuterated Arylamine Dna Adducts For Use In The Development Of An Isotope Dilution Lc/Ms/Ms Method, Philip Dmitri Olsen
The Synthesis Of Deuterated Arylamine Dna Adducts For Use In The Development Of An Isotope Dilution Lc/Ms/Ms Method, Philip Dmitri Olsen
LSU Doctoral Dissertations
Polycyclic aromatic amines (arylamines) are a class of chemical carcinogens that are prevalent in environmental and industrial settings. In order to study the mechanism of their toxicity a quantitative and qualitative detection method was developed to measure the C8-adenine adducts of benzidine and 2-aminofluorene in DNA samples. To do this a novel synthetic method using a palladium catalyst was developed to prepare authentic and deuterated arylamine adducts to serve as standards. These standards were then used to develop a high performance liquid chromatography, electrospray, tandem mass spectrometry, isotope dilution, detection method. To demonstrate the validity of this method two spike …