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Articles 391 - 420 of 449
Full-Text Articles in Chemistry
Synthesis, Characterization And Properties Of Cooper(Ii) Beta-Diketonate Macrocycles, Sylvester Burton
Synthesis, Characterization And Properties Of Cooper(Ii) Beta-Diketonate Macrocycles, Sylvester Burton
LSU Doctoral Dissertations
This dissertation deals with the synthesis and properties of multidentate β-diketone ligands and their transition-metal complexes. (1) We prepared two bis(β-diketones), C1BAH2 and p-XBAH2 (see sketch below), determined their crystal structures, and studied their reactions with copper(II). We envisioned that they would form macrocyclic complexes with 3-6 metal atoms. In both cases, although the initial products are soluble, as expected for the desired molecular products, we were unable to isolate well-behaved molecular solids. In the case of C1BAH2, this may be because the cyclic product requires an unusual combination of conformations of …
Synthesis, Characterization And Application Of Polymeric Surfactants In Micellar Electrokinetic Chromatography: Use Of Ionic Liquids As Modifiers, Simon M. Mwongela
Synthesis, Characterization And Application Of Polymeric Surfactants In Micellar Electrokinetic Chromatography: Use Of Ionic Liquids As Modifiers, Simon M. Mwongela
LSU Doctoral Dissertations
The goal of the research presented in this dissertation is to synthesize, characterize, and apply a novel chiral amino acid-based surfactant and achiral sulfate-based surfactants for the effective separations of chiral and achiral compounds in micellar electrokinetic chromatography (MEKC). The first part of this research involves novel synthesis, characterization, and application of polysodium oleyl-L-leucyl-valinate (poly-L-SOLV) for the separation of chiral compounds in MEKC. Surface tensiometry, proton nuclear magnetic resonance, infrared spectroscopy, densitometry and analytical ultracentrifugation were used as the characterization techniques. Optimal MEKC separating conditions were established by varying surfactant concentration, buffer concentration and pH, applied voltage, and capillary temperature. …
Molecular Recognition And Its Underlying Mechanisms In Molecularly Imprinted Polymers, Ryan Simon
Molecular Recognition And Its Underlying Mechanisms In Molecularly Imprinted Polymers, Ryan Simon
LSU Doctoral Dissertations
Molecular recognition in molecularly imprinting polymers (MIPs) is governed by two mechanisms: pre-organization of functional groups and shape specificity of the binding site. While pre-organization of functional groups has been studied extensively, shape specificity of the binding site has not been rigorously explored. The goal of this research is to determine the influence of shape specificity on molecular recognition in MIPs (Chapter 2). Once shape selectivity was proven to play a vital role in molecular recognition, it was important to determine if pre-organization of functional groups or shape specificity was the dominating factor in determining molecular recognition in the binding …
Detection Of Biologically Important Molecules, Kyukwang Kim
Detection Of Biologically Important Molecules, Kyukwang Kim
LSU Doctoral Dissertations
Anions play important roles in biological systems. The design of anion sensors has been of great interest. The selective detection of a specific anion is particularly challenging. In the first chapter, I describe the synthesis of a TBS-protected fluorescein dye (1.1) and its use for the selective detection of fluoride. Solutions of 1.1 either in DCM or in aqueous media at physiological pH show the excellent selectivity towards fluoride to afford color formation while solutions of other interfering anions remain colorless. The monitoring of homocysteine (Hcy) and cysteine (Cys) levels is important since they are biomarkers associated with Alzheimer’s and …
Analytical Separations Using Polymetric Surfactants, Mary Waithira Kamande
Analytical Separations Using Polymetric Surfactants, Mary Waithira Kamande
LSU Doctoral Dissertations
The goal of the research presented in this dissertation is to develop effective analytical methods for the separation of both achiral and chiral analytes using polymeric surfactants. Three analytical techniques are employed to accomplish this objective: open-tubular capillary electrochromatography (OT-CEC), open-tubular capillary electrochromatography coupled to mass spectrometry (OT-CEC/MS), and micellar affinity gradient focusing (MAGF). This research work presents novel application of polymeric surfactants that contributes to improved separations of difficult to separate analytes. The first part focuses on the application of an achiral polyelectrolyte multilayer (PEM) coating using OT-CEC. The PEM coating consisting of the cationic polymer poly (diallyldimethylammonium chloride), …
Characterization Of A Modified Poly(Propylene Imine) Dendrimer Host System, Amy D. Morara
Characterization Of A Modified Poly(Propylene Imine) Dendrimer Host System, Amy D. Morara
LSU Doctoral Dissertations
The research in this dissertation focuses on the design of a novel redox-responsive host system that has the ability to encapsulate guest molecules. The host at hand is a tri(ethylene oxide), TEO, pyrrole-terminated PPI dendrimer that possesses water-solubility as a result of the presence of the TEO chains on the pyrrole groups and redox-responsive activity from the pyrrole groups after their oligomerization. The pyrrole moieties at the periphery of the dendrimer exhibit the ability to be oligomerized by oxidation chemistry, and this is shown to aid in the retention and egress of guest molecules located within the dendrimer interior. These …
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 …
Hydrophobic Guar Gum Derivatives Prepared By Controlled Grafting Processes For Hydraulic Facturing Applications, Ahmad Bahamdan
Hydrophobic Guar Gum Derivatives Prepared By Controlled Grafting Processes For Hydraulic Facturing Applications, Ahmad Bahamdan
LSU Doctoral Dissertations
The synthesis of new water soluble guar gum derivatives is described. Introduction of polyalkoxyalkyleneamide grafts to guar gum or hydroxyopropyl guar was achieved in a three step process: carboxymethylation with sodium chloroacetate, esterification with dimethyl sulfate and amidation with a series of polyalkoxyalkylene-amines. The process steps were followed using infrared spectroscopy; the grafted guar derivatives were characterized using FT-IR and 1H NMR. A series of hydroxypropyl guar derivatives with degrees of carboxymethylations ranging from 0.15-0.25 were modified with polyalkoxyalkyleneamines with molecular weights ranging from 300-3000. The ratio of oxypropylene to oxoethylene units in the polyalkoxyalkyleneamines was varied from 9/1 …
The Stereoselective Synthesis Of The Butyrolactone-Bridged [8-5-5] Tricyclic Ring Systems Of (+/-)-Asteriscanolide Via The Titanium-Mediated Hetero-Pauson-Khand Reaction, Mohamed G. Sherriff
The Stereoselective Synthesis Of The Butyrolactone-Bridged [8-5-5] Tricyclic Ring Systems Of (+/-)-Asteriscanolide Via The Titanium-Mediated Hetero-Pauson-Khand Reaction, Mohamed G. Sherriff
LSU Doctoral Dissertations
The stereoselective construction of the tricyclic ring system of asteriscanolide from cyclooctadiene has been achieved. The synthesis involves two main steps; the synthesis of the aldehyde precursor(5)and the titanium-mediated cabocyclization of 5 to make the three rings of 43 stereoselectively.
Shear Induced Orientation In Polymer-Clay Solutions And Their Influence On The Structure In Multilayered Films, Matthew Michael Malwitz
Shear Induced Orientation In Polymer-Clay Solutions And Their Influence On The Structure In Multilayered Films, Matthew Michael Malwitz
LSU Doctoral Dissertations
The influence of shear on viscoelastic solutions of poly(ethylene oxide) (PEO) and clay (Cloisite, CNA) was investigated by rheology and small angle neutron scattering (SANS) under shear. These measurements determined the shear-induced orientation of the clay and the polymer as well as their relaxation behavior after cessation of shear. Comparison of PEO-CNA solutions (~100 nm diameter platelets) to previously studied PEO-Laponite gels (~30 nm diameter platelets) found that the orientation of CNA platelets occurs at much lower shear rates. Additionally, the relaxation times were much longer for CNA platelets than for Laponite platelets. From these solutions and gels, multilayered nanocomposite …
Capillary And Microchip Gel Electrophoresis Using Multiplexed Fluorescence Detection With Both Time-Resolved And Spectral-Discrimination Capabilities: Applications In Dna Sequencing Using Near-Infrared Fluorescence, Li Zhu
LSU Doctoral Dissertations
Increasing the information content obtainable from a single assay and system miniaturization has continued to be important research areas in analytical chemistry. The research presented in this dissertation involves the development of a two-color, time-resolved fluorescence microscope for the acquisition of both steady-state and time-resolved data during capillary and microchip electrophoresis. The utility of this hybrid fluorescence detector has been demonstrated by applying it to DNA sequencing applications. Coupling color discrimination with time-resolved fluorescence offers increased multiplexing capabilities because the lifetime data adds another layer of information. An optical fiber-based fluorescence microscope was constructed, which utilized fluorescence in near-IR region, …
Synthesis Of Symmetric And Asymmetric Water-Soluble Porphyrin Derivatives, Caroline Owendi Ongayi
Synthesis Of Symmetric And Asymmetric Water-Soluble Porphyrin Derivatives, Caroline Owendi Ongayi
LSU Doctoral Dissertations
Novel symmetric and asymmetric water-soluble tetrabenzoporphyrin are synthesized in relatively good yields. These compounds are synthesized by the condensation of butanopyrrole with several aldehydes that contain masked water solubilizing groups followed by metal insertion, oxidation and demetallation and deprotection of the masked solubilizing groups. The biological evaluation (in vitro and in vivo) studies are described in addition to the photophysical evaluations of the corresponding compounds. A novel versatile route to the syntheses of novel free-bases and metallo-benzoylbiliverdin is discussed. The treatment of metal free-dodecasubstituted porphyrin with sodium nitrite and trifluoroacetic acid at room temperature in the presence of oxygen affords …
Synthetic Development And Application Of Compounds With Biological Relevance, Jeffery Caleb Clark
Synthetic Development And Application Of Compounds With Biological Relevance, Jeffery Caleb Clark
LSU Doctoral Dissertations
Nature has provided a vast number of compounds that have medicinal application. The use of these compounds provided by nature however, is limited by the amount of a specific compound that nature provides. The synthesis of these molecules and their derivatives provides an even greater number of compounds for biological screening. Various pyrroles, the heterocyclic building blocks of porphyrins, can be prepared synthetically over several steps. The implementation of carboranes on pyrrole rings intrinsically provides substrates that can be converted into porphyrins bearing carborane substituents. The condensation of these carboranylpyrroles with carboranylaldehydes provides carboranylporphyrins bearing a higher order of carborane …
Characterization Of Aged Polymer Modified Asphalt Cements For Recycling Purposes, Codrin Daranga
Characterization Of Aged Polymer Modified Asphalt Cements For Recycling Purposes, Codrin Daranga
LSU Doctoral Dissertations
Since polymer modified asphalt cement (PMAC) has been employed for a decade, the lifetime and wear on some of these pavements is reaching a stage where resurfacing is necessary. This research focuses on the characterization of aged polymer modified asphalt cements (PMAC) to evaluate their potential for recycling. A styrene-butadiene-styrene tri-block (SBS) polymer modified asphalt cement was selected and characterized using standard asphalt binder qualification techniques, i.e., the Superpave PG protocol. We developed a procedure to characterize the relative concentration of polymer in asphalt cements by gel permeation chromatography (GPC). Infrared spectrographic, thermogravimetric and rheological techniques were used to identify …
Enantioselective Syntheses And Chemical Investigations Of Plant-Derived Bioactive Volatile Compounds, Anne Marie Sauer
Enantioselective Syntheses And Chemical Investigations Of Plant-Derived Bioactive Volatile Compounds, Anne Marie Sauer
LSU Doctoral Dissertations
Research, inspired by nature, provides ample opportunity for discovery, ingenuity, and creative endeavor. For these reasons, the work and accomplishments presented herein focus on the total syntheses and related investigations of a variety of natural product derivatives, specifically (+)-nootkatone and jasmone. While the former consists of several independent projects: (a) an enantioselective synthetic route to (+)-nootkatone and derivatives, (b) examination of the valencane ring system, (c) determination of the absolute configuration of (+)-nootkatone, and (d) rearrangements of various sesquiterpenoid derivatives; the latter focuses on the construction ofƒndelta, epsilon-unsaturated carbonyl compounds, hetero Pauson-Khand substrates, via [3,3]-sigmatropic rearrangements.
Infrared And X-Ray Spectroscopic Studies Of The Copper(Ii) Oxide Mediated Reactions Of Chlorinated Aromatic Precursors To Pcdd/F, Steven L. Alderman
Infrared And X-Ray Spectroscopic Studies Of The Copper(Ii) Oxide Mediated Reactions Of Chlorinated Aromatic Precursors To Pcdd/F, Steven L. Alderman
LSU Doctoral Dissertations
Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F) are toxic compounds produced in combustion systems such as incinerators, and their emissions are an important environmental issue. Chlorinated phenols and benzenes form PCDD/F through heterogeneous reactions following adsorption onto fly-ash surfaces. Current research implicates transition metals in promoting formation of phenoxyl radicals that react to form PCDD/F, although this has not been studied extensively. This objective of this work is to better understand PCDD/F formation from chlorinated aromatic precursors. Using 2 chlorophenol as a model PCDD/F precursor and silica as a fly-ash surrogate, time-dependent chemisorption of 2 chlorophenol onto silica was studied in situ …
Separation And In Situ Catalytic Testing Of A Dirhodium Tetraphosphine Catalyst, Bobby Lloyd Barker
Separation And In Situ Catalytic Testing Of A Dirhodium Tetraphosphine Catalyst, Bobby Lloyd Barker
LSU Doctoral Dissertations
Attempts to study the asymmetric hydroformylation abilities of [rac-Rh2(nbd)2(et,ph-P4)](BF4)2 were made through the separation of the enantiomers of et,ph-P4 using a chiral HPLC column. Efforts were also made to optimize the NiCl2 separation chemistry for the methyl analogue of et,ph-P4 for use in asymmetric hydroformylation. A study of hydroformylation of olefins using [rac-Rh2(nbd)2(et,ph-P4)](BF4)2 in ionic liquids was also performed, leading directly to the important (and unexpected) effect of increased hydrogen pressure on [rac-Rh2(nbd)2(et,ph-P4)](BF4)2 in the acetone/water system to …
Investigation Of Structure-Property Relationships Of Heavy-Fermion Materials, Robin Macaluso
Investigation Of Structure-Property Relationships Of Heavy-Fermion Materials, Robin Macaluso
LSU Doctoral Dissertations
This work focuses on how local structural features influence large effective masses, magnetism, and superconductivity that are yet to be understood in heavy-fermion materials. Three sets of structurally-related materials are discussed in light of dimensionality, layering effects, choice of transition metal, coordination, and structural distortions: LnnMIn3n+2 (Ln = La, Ce; n = 1, 2, ‡; M = Co, Rh, Ir), CePdGa6, and Ce2PdGa12, and CeNiSb3. The LnnMIn3n+2 (n = 1, 2, ‡; Ln = La, Ce; M = Rh, Ir) intergrowth homologous series presents a unique opportunity to study structure-property relationships. LnnMIn3n+2 (Ln = La, Ce; n = 1, 2; …
Attachment Of Oligonucleotide Probes To Polymer Biochips And Its Application For The Detection Of Point Mutations, Yun Wang
LSU Doctoral Dissertations
This dissertation is on the fabrication of polymer-based microfluidic arrays for the detection of genetic mutations. Poly(methyl methacrylate) was chosen as one of the polymer substrate materials due to its low background noise, low adsorption of biomolecules, and low assembly temperature. The surface modification of polymer substrates for covalent attachment of oligonucleotide probes, the construction of fluidic channels/arrays, and hybridization kinetics will be covered. As an example of the application, point mutation detection using immobilized arrays constructed in microfluidic devices will be demonstrated. The PMMA surface was derivatized with N-lithioethylenediamine solution to introduce amine groups, which were utilized for the …
Comparison Studies Of The Mechanistic Formation Of Polyhalogentaed Dibenzo-P-Dioxins And Furans From The Thermal Degradation Of 2-Bromophenol And 2-Chlorophenol, Catherine Spearing Evans
Comparison Studies Of The Mechanistic Formation Of Polyhalogentaed Dibenzo-P-Dioxins And Furans From The Thermal Degradation Of 2-Bromophenol And 2-Chlorophenol, Catherine Spearing Evans
LSU Doctoral Dissertations
Emissions of polychlorinated dibenzo-p-dioxins and furans (PCDD/Fs) and polybrominated dibenzo-p-dioxins and furans (PBDD/Fs) from hazardous waste incinerators, and many other sources for combustion have been considered environmentally hazardous and a major health threat. Recently, a growing number of materials containing brominated hydrocarbons, commonly used flame retardants, have been disposed in municipal and hazardous waste incinerators. This results in the increased potential for formation of PBDD/Fs and other hazardous combustion by-products. In contrast to chlorinated hydrocarbons, the reactions of brominated hydrocarbons have been studied only minimally. In fact, studies have shown that brominated phenols form higher yields of PBDD/Fs than the …
Dynamics Of Complex Polymer Solutions: Putting Diffusion To Work And Exploring Rigid Rod Diffusion, Garrett John Doucet
Dynamics Of Complex Polymer Solutions: Putting Diffusion To Work And Exploring Rigid Rod Diffusion, Garrett John Doucet
LSU Doctoral Dissertations
This dissertation is concerned with random coil and rodlike polymer diffusion in complex solutions. The development of fluorescence photobleaching recovery, FPR, as a technique to determine polymer molecular weight distributions by measuring the diffusion distribution and converting it to a molecular weight distribution using a calibration curve is first covered. Fluorescently tagged probes were individually dissolved in polymer solutions at negligible amounts and measured with FPR to construct the calibration curve of self-diffusion vs. molecular weight. Once calibration curves were constructed, bimodal distributions were separated using the matrices corresponding to the calibration curves. The diffusion of the probes and separation …
The Syntheses Of Novel Indicators And Materials For Chiral Separation, Rolanda Johnson
The Syntheses Of Novel Indicators And Materials For Chiral Separation, Rolanda Johnson
LSU Doctoral Dissertations
The colorimetric properties of resorcinarene solutions had not been fully investigated since von Baeyer's initial synthesis. We find that the solutions containing resorcinarene macrocycles develop color upon heating or standing. In the presence of saccharides, these solutions exhibit significant color changes which are readily observable by visual inspection. We determined that the solution color is due to macrocycle ring opening and oxidation. The optical responses to saccharides are due to complexation of the sugar with the acyclic chromophores. We have applied these mechanistic insights towards the challenging problems of the visual detection of saccharides and other important biologically analytes. In …
Applications Of The Titanium Catalyzed Cyclocarbonylation Towards Natural Product Syntheses, Jongtae Yang
Applications Of The Titanium Catalyzed Cyclocarbonylation Towards Natural Product Syntheses, Jongtae Yang
LSU Doctoral Dissertations
Recently an efficient methodology, a hetero Pauson-Khand reaction, based on titanium-catalyzed cyclocarbonylation of tethered enals for the general preparation of ¥ã-butyrolactone rings, which are typically embedded in polycyclic systems of many natural products was reported. To demonstrate this new strategy, the total syntheses of the natural products asteriscanolide and ginkgolide were investigated. The first part of this work is dedicated to synthetic efforts toward the total synthesis of asteriscanolide. Approaches highlighted by the [2,3]-Wittig rearrangement, the thermal silyloxy-Cope rearrangement, and a titanium-catalyzed cyclocarbonylation, which is the pivotal step to afford the ¥ã-butyrolactone ring. This study firmly established the utility of …
Synthesis And Characterization Of Superparamagnetic Silica--Homopolypeptide Composite Particles, Sibel Turksen
Synthesis And Characterization Of Superparamagnetic Silica--Homopolypeptide Composite Particles, Sibel Turksen
LSU Doctoral Dissertations
Hierarchical construction and characterization of core-shell composite particles of interest are presented. The research described shows interest in new types of polymers that provide chirality and responsiveness which have been ignored for so long. The general synthetic design described in this document can be readily used as a model for other systems. Core-shell composite systems of interest consist of silica or silica-coated cobalt cores grafted with a homopolypeptide shell, mostly poly(epsilon-carbobenzyloxy-L-lysine) or poly(gamma-benzyl-L-glutamate). Core particles were decorated with amino groups through a silylation reaction. The amino groups initiated the polymerization (with attachment) of N-carboxyanhydride (NCA) monomers, resulting in a homopolypeptide …
Synthesis, Separation And Reactivities Of Multidentate Phosphine Ligands And Investigation Into Dirhodium Hydroformylation And Hydrocarboxylation Catalysis, David Aubry
LSU Doctoral Dissertations
A dirhodium homogeneous hydroformylation catalyst based on a tetraphosphine ligand, rac-Et2PCH2CH2P(Ph)CH2P(Ph)CH2CH2PEt2, rac-et,ph-P4, is under investigation. The ligand synthesis produces a racemic mixture and a facile and efficient method of separation of the racemic and meso diastereomers was achieved through reaction of et,ph-P4 with two equivalents of NiCl2 in EtOH to yield an almost quantitatively isolable precipitate of meso-Ni2Cl4(et,ph-P4) and the soluble rac-Ni2Cl4(et,ph-P4). Subsequent cyanolysis of these complexes liberates the et,ph-P4 ligand, and the …
Tuning Polymeric Chiral Surfactants For Enhanced Enantiomeric Recognition In Micellar Electrokinetic Chromatography, Jepkoech Tarus
Tuning Polymeric Chiral Surfactants For Enhanced Enantiomeric Recognition In Micellar Electrokinetic Chromatography, Jepkoech Tarus
LSU Doctoral Dissertations
The research presented in this dissertation involves the synthesis, modification, characterization, and the application of polymeric surfactants in micellar electrokinetic chromatography (MEKC). Sodium undecenoyl-L-Leucinate (L-SUL) was synthesized and modified by use of alkali metal counterions, alcohols, and Triton X-102. Characterization of the modified poly-L-SUL was performed in order to elucidate the structural changes on the surfactants by use of four techniques. While surface tensiometry was used for the determination of the critical micelle concentration (cmc), fluorescence measurements were used for the determination of the polarity of the modified polymeric surfactants. The information about the size of the polymeric surfactants was …
New Insights Into The Binding Site Formation And The Performance Of Molecularly Imprinted Polymers, Hyunjung Kim
New Insights Into The Binding Site Formation And The Performance Of Molecularly Imprinted Polymers, Hyunjung Kim
LSU Doctoral Dissertations
Molecularly imprinted polymers (MIPs) are finding important applications in the field of separation science, catalysis, sensor, and immunoassays. To optimize the performance of the MIPs, it is essential to understand the underlying mechanism of the process. This research focuses on understanding binding site formation and performance, and improvement of the MIPs. Chapter 1 introduces the concept of the MIPs, and binding isotherm and affinity distribution of heterogeneous binding sites in the MIPs. Chapter 2 describes fundamental studies conducted to understand the binding site formation of the MIPs. The number of binding sites (N) and the number average association constant (Kn) …
Analytical Separations Using Packed And Open-Tubular Capillary Electrochromatography, Constantina P. Kapnissi
Analytical Separations Using Packed And Open-Tubular Capillary Electrochromatography, Constantina P. Kapnissi
LSU Doctoral Dissertations
The goal of the research reported in this dissertation is to develop packed and open-tubular capillary electrochromatographic methods for improved achiral and chiral separations of various classes of analytes. The first part of this research involves the separation of seven benzodiazepines by the use of the packed mode of capillary electrochromatography (CEC) and a 40 cm packed bed of Reliasil 3 μm C18 stationary phase. Optimal conditions were established by varying the mobile phase, the amount of organic modifier, the buffer concentration, the applied voltage, and the column temperature. The second part of this research focuses on the open-tubular …
Microelectrophoresis System Utilizing Conductivity Detection Analyzing Biological Molecues, Michelle Galloway
Microelectrophoresis System Utilizing Conductivity Detection Analyzing Biological Molecues, Michelle Galloway
LSU Doctoral Dissertations
Microfabrication technology has proven to be a valuable tool for creating polymer-based devices utilized in chemical and biochemical assays. Although, reducing the size of the device allows for short analysis times and reduces the reagent demand to ultrasmall volumes (< 1 nanoliter), a resulting consequence is the constraint placed on the limits of detection associated with the detector hardware required for readout. To overcome such constraints, laser-induced fluorescence (LIF) is often employed as a detection method as it provides low detection limits, which approach the single molecule level. Unfortunately, most LIF systems do not offer the benefits of miniaturization, with the detector components (i.e. laser, optics, filters) often times requiring a much larger footprint compared to the device. Another readout strategy that has shown promise for these devices is conductivity detection. Detection can be accomplished using either conventional-size or microfabricated electrodes, which can be integrated on the device. Although conductivity has been commonly used to detect inorganic or small organic species, the potential for detection of biological species has received little attention. In this work, an integrated conductivity detector was developed for the analysis of amino acids, peptides, proteins, and oligonucleotides (double-stranded DNA). Using the detector, mass detection sensitivities in the range of 10-18 - 10-21 moles were achieved. To increase the throughput of the system a state-of-the-art, multichannel device with a conductivity array detector was devised. This device, which consists of a 16-channel fluidic network and a printed circuit board, is geared toward automating three-processing steps onto a single fluidic platform including purification, preconcentration and detection for downstream parallel processing.
Synthesis And Antibacterial Assessment Of Water-Soluble Hydrophobic Chitosan Derivatives Bearing Quaternary Ammonium Functionality, Mrunal R. Thatte
Synthesis And Antibacterial Assessment Of Water-Soluble Hydrophobic Chitosan Derivatives Bearing Quaternary Ammonium Functionality, Mrunal R. Thatte
LSU Doctoral Dissertations
Chitosan is a naturally occurring, bio-degradable, non-toxic, non-allergenic bio-polysaccharide derived from chitin, found in abundance in nature. Studies aimed at deriving newer applications of chitosan are hence of interest. Among these, one of the focuses of investigations is aimed at excellent antimicrobial activity demonstrated by chitosan. In this context, certain quaternary ammonium derivatives of chitosan have been shown in the past to be highly effective antibacterial materials. In the present study, substituted chitosan derivatives were synthesized and further quaternized using Quat-188 to produce water soluble derivatives at neutral pH. The antibacterial assessments of the quaternized derivatives of substituted chitosan were …