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Full-Text Articles in Physical Sciences and Mathematics
Improving Coupled Enzyme Assays With Capillary Electrophoresis, Thu Hoai Nguyen
Improving Coupled Enzyme Assays With Capillary Electrophoresis, Thu Hoai Nguyen
LSU Doctoral Dissertations
The goal of this project is to address limitations of coupled enzyme assays using capillary electrophoresis (CE). In some enzyme assays, it is ineffective to directly detect products and substrates spectroscopically (absorption or fluorescence). Coupling the enzyme-catalyzed reaction of interest with another enzyme-catalyzed reaction allows for indirect detection of product formation or substrate depletion for the target enzyme. While conventional coupled enzyme assays are facile for kinetic measurements, they can be problematic for inhibition screening due to spectral and inhibitor interferences. To address these limitations of coupled assays, CE has been used to develop enzyme assays for acetyl-coenzyme A carboxylase …
Analysis Of Protein Aggregates And Synthetic Nanoparticles Using Capillary Electrophoresis With Light Scattering And Fluorescence Detection, Suresh Chandra Regmi
Analysis Of Protein Aggregates And Synthetic Nanoparticles Using Capillary Electrophoresis With Light Scattering And Fluorescence Detection, Suresh Chandra Regmi
LSU Doctoral Dissertations
The goal of the research presented in this dissertation is to develop capillary electrophoresis (CE) based analysis techniques for the characterization of individual particles including amyloid beta (Aâ) peptide aggregates and to apply these methods to study the aggregation of Aâ peptides. Protein self-assembly into ordered aggregates is a common and important process in normal biological function, but this process is also involved in several diseases. Amyloid beta peptide aggregation is linked to Alzheimer’s disease. Thioflavin T (ThT) has been used as a fluorescent probe for the detection of Aâ aggregation. Based on previous observations of false positive fluorescent signals …
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 …
On-Line Laser Desorption/Ionization Mass Spectrometry, Damien A. Narcisse
On-Line Laser Desorption/Ionization Mass Spectrometry, Damien A. Narcisse
LSU Doctoral Dissertations
Interfaces for on-line laser desorption/ionization mass spectrometry are presented in this dissertation. An on line laser desorption interface allows samples to be introduced directly into the mass spectrometer for high-throughput applications. For this research, a linear time of flight mass spectrometer was constructed with an ionization source designed to accept various laser desorption interfaces. A ball inlet interface was used for continuous analyte deposition at atmospheric pressure and vacuum ionization. A solvent-based cleaning system and a separate capillary for MALDI matrix delivery was utilized for continuous on line sampling with the ball inlet interface. Microfluidic devices were brought into contact …
Bioanalytical Methods For Studies Of Homocysteine And Novel Cardiovascular Disease Indicators, Arther T. Gates
Bioanalytical Methods For Studies Of Homocysteine And Novel Cardiovascular Disease Indicators, Arther T. Gates
LSU Doctoral Dissertations
This dissertation explores the development of analytical methods for studies of CVD biomarkers and related biomolecular indicators. Initially, spectroscopic studies were conducted to investigate the chemical reactivity of homocysteine (Hcy), an independent CVD risk factor and serological biomarker. Consequently, we proposed an alternate theory for in vivo Hcy clearance based on spontaneous pyridoxal tetrahydrothiazine (PT) formation from Hcy and pyridoxal. The validity of PT-assisted Hcy clearance was further evaluated by use of capillary electrophoretic methods, which allowed rapid monitoring of protein oligomerization in PT-protein reaction mixtures. The results of these studies suggest that PT formation is a plausible mechanism for …
Development Of Analytical Techniques For The Analysis Of Submicron Particles And Protein Aggregates, Yohannes H. Rezenom
Development Of Analytical Techniques For The Analysis Of Submicron Particles And Protein Aggregates, Yohannes H. Rezenom
LSU Doctoral Dissertations
The goal of the research presented in this dissertation is to develop analytical techniques for the analysis of heterogeneous mixtures of submicron particles and protein aggregates. In Chapter 2, a simple and reproducible technique for constructing perfectly aligned gaps in fused-silica capillaries has been developed for postcolumn reagent addition with capillary electrophoresis (CE) to take advantage of laser-induced fluorescence (LIF) detection. This technique uses laser ablation with a Nd:YAG laser to create gaps of 14.0 ¡Ó 2.2 ƒÝm. These structures have been used for reagent addition for postcolumn derivatization with LIF detection and have been tested for the separation of …
An Evaluation Of The Enantiomeric Recognition Of Amino Acid Based Polymeric Surfactants And Cyclodextrins Using Spectroscopic And Chromatographic Methods, Bertha Cedillo Valle
An Evaluation Of The Enantiomeric Recognition Of Amino Acid Based Polymeric Surfactants And Cyclodextrins Using Spectroscopic And Chromatographic Methods, Bertha Cedillo Valle
LSU Doctoral Dissertations
The scope of this dissertation is to explore the enantiomeric recognition properties of amino acid based polymeric surfactants using a combination of analytical techniques including chromatographic and spectroscopic methods. Chapter 1 includes an introduction to chirality and chiral separations using capillary electrophoresis. Using cyclodextrin modified micellar electrokinetic chromatography (CD-MEKC), the enantioseparation of three binaphthyl derivatives using native alpha- and beta-cyclodextrins in combination with various diastereomers of chiral polymeric surfactants (PS) was examined. A reversal of enantiomeric order was observed with the enantiomers of (1,1 S-binaphthyl-2,2 S-diamine (BNA) and (1,1 S-binaphthol (BOH) due to a competition between the two chiral selectors …
Solid-Phase Dna Sequencing Reactions Performed In Micro-Capillary Reactors And Solid-Phase Reversible Immobilization In Microfluidic Chips For Purification Of Dye-Labeled Dna Sequencing Fragments, Yichuan Xu
LSU Doctoral Dissertations
The research presented in this dissertation involves micro-capillary reactors for solid phase DNA sequencing, the identification of dye terminator sequencing fragments with time-resolved methods, and purification of dye-labeled DNA fragments using solid- phase reversible immobilization in microfluidic chips. Solid-phase micro-reactors have been prepared for DNA sequencing applications using slab gel electrophoresis. A PCR product was immobilized to the interior wall of a fused-silica capillary tube via a biotin-streptavidin linkage. Solid-phase sequencing was carried out in micro-capillary reactors using a four-lane, single color dye primer chemistry strategy. The read length was found to be 589 bases. The complementary DNA fragments generated …
Synthesis, Characterization, And Applications Of Novel Pseudostationary Phases In Micellar Capillary Electrophoresis For Separation Of Chiral And Archiral Compounds H[Electronic Resource], Cevdet Akbay
LSU Doctoral Dissertations
The research presented in this dissertation involves the synthesis, characterization, and the use of novel surfactants, including both micelles and vesicles, as pseudostationary phases in micellar capillary electrophoresis (MCE) for the separation of achiral and chiral compounds. Separation of environmental pollutants such as 2 to 6-ring polycyclic aromatic hydrocarbons (PAHs) was achieved using poly(sodium undecylenic sulfate). A baseline separation of all 16 PAHs was possible for the first time in MCE by a single-surfactant system. In addition, a surfactant with a phosphated head group, i.e., di(2-ethylhexyl)phosphate (DEHP), was also introduced as a novel pseudostationary phase for separation of 21 weakly …
Capillary And Microdevice Electrophoretic Tools For Genetic Analyses: Heteroduplex Analysis For Tuberculosis Drug Susceptibility And Ligase Detection Reaction For Colorectal Cancer Detection, Gloria Thomas
LSU Doctoral Dissertations
The traditional format of electrophoresis, the slab gel, is quickly being replaced by capillary and microdevice platforms, which offer improvements in cost, resolution, speed, quantitation and automation in genetic analyses. These techniques also employ a variety of separation matrices while the slab gel is limited to agarose and polyacrylamide. The research presented here explores the use of these electrophoretic formats for the detection of single nucleotide mutations using two genetic models associated with human disease. Slab gel based heteroduplex analysis (HDA), a popular mutation scanning method, uses a specially designed universal heteroduplex generator (UHG) containing controlled variation to enhance the …