Chemistry Commons^™

Electrochemistry Of Pani/Metal Composites In Basic Solutions, Tamthinhan Quy

UNLV Theses, Dissertations, Professional Papers, and Capstones

Polyaniline (PANI) has been extensively investigated due to its unique conductivity, which is primarily dependent on the oxidation state of the material and the solution pH. PANI is an insulator when it is oxidized, and the solution pH exceeds four. Numerous attempts to extend PANI's conductivity to neutral and alkaline environments have been unsuccessful. However, our previous study has demonstrated that PANI/Pd composite is conductive and catalytically active in a basic solution, pH ∼ 12. Therefore, the conductivity and the electrochemical properties of PANI composites including PANI/Au, PANI/Pd and PANI/Pt were evaluated in basic solutions. The fundamental studies of PANI/metal …

Influence Of Ionic Mobile Phase Additives With Low Charge Delocation On The Retention Of Ionic Analytes In Reversed Phase Hplc, Cesar Florez

Seton Hall University Dissertations and Theses (ETDs)

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Studies Toward The Development Of A Microelectrode Array For Detection Of Dopamine Through Redox Cycling, Anupama Aggarwal

Graduate Theses and Dissertations

Redox cycling is an electrochemical technique that cycles the reversible redox species between its oxidative states repeatedly on generator and collector electrodes. Two or more individually-addressable microelectrodes located close to each other allow redox cycling to be possible. Electrochemical behavior of a biologically important molecule, dopamine is examined under redox cycling conditions. To our knowledge, this is the first report on detection of physiological concentration of dopamine in presence of up to 100 times excess ascorbate with the use of redox cycling, without the involvement of polymer coating such as Nafion®.

Microfabrication was used to produce different geometries (parallel bands …

Dynamics And Catalytic Resolution Of Selected Chiral Organolithiums, Timothy Kum Beng

Graduate Theses and Dissertations

One of the most important developments of the last decade has been the emergence of new methods to dynamically resolve racemic organolithiums using stoichiometric amounts of the chiral ligand. When this concept is implemented successfully, it obviates the need for covalently attached chiral auxiliary based methods, asymmetric deprotonation, and asymmetric synthesis of a precursor stannane as ways to access enantioenriched organolithium compounds for use in asymmetric synthesis. Since certain electrophiles consume the chiral ligand, it is desirable to render this process catalytic in the chiral ligand.

As part of a larger study on the amenability of chiral organolithiums to a …

Dynamic Modeling And Characteristic Analysis Of Proton Exchange Membrane Fuel Cell, Qiu-Hong Jia, Ming Han, Bin Deng, Cai-Zhi Zhang

Journal of Electrochemistry

In this paper, a dynamic model of PEMFC is developed to estimate the dynamic performance of PEMFC by analyzing in detail the influence factors of voltage of PEMFC including various losses. The partial pressure of hydrogen and oxygen is obtained using the differential form of the ideal-gas equation in this model. The steady-state model is obtained by setting reasonable parameter values. The simulation results and experimental results have good consistency, which shows that the simulation model is correct, reasonable and effective. It analyzed the dynamic response characteristics of the output voltage and the partial pressure of hydrogen in condition of …

Preparation And Characterization Of A Composite Of Gold Nanoparticles And Single-Walled Carbon Nanotubes And Its Potential For Heterogeneous Catalysis, Anne Shanahan, James Sullivan, Mary Mcnamara, Hugh Byrne

Articles

A single-walled carbon nanotube-supported gold nanoparticle composite was prepared and characterized by X-ray diffraction, scanning transmission electron microscopy/scanning electron microscopy/transmission electron microscopy, energy-dispersive X-ray analysis, atomic absorption spectroscopy, nitrogen adsorption, Raman spectroscopy, and ultraviolet-visible spectroscopy. The Au particles were found to be crystalline, with a well-defined and narrow particle-size distribution, centered around 7 nm. The activity and selectivity of the composite for solventless aerobic oxidation of a secondary alcohol were examined, and a conversion efficiency of 95% was obtained.

An Lcms Based Assay For Detection And Quantification Of Bacterial Cell Wall Intermediates, Chandra Sekhar Arigapudi

All Capstone Projects

The main objective of my project is to determine the bacterial cell wall intermediates in E.coli and develop an LCMS method that Phosphomycin is a PEP analogue that irreversibly inhibits UDP-GluNAc-enolpyruvate transferase (MurA enzyme), which prevents the formation of N-acetyl muramic acid, which is an essential element in the Peptidoglycan cell wall. Antibacterial agents have a tremendous impact on human health. Most of the antibacterial agents, including beta lactams target the bacterial cell wall biosynthesis.The pathway for Escherichia coli is shown in page 19. Among the most widely used antibiotics, beta lactams inhibit the penicillin binding protein (PBPs)which block the …

Evaluation And In Vitro Studies Of Folate Peg Biotin And Other Peg Agents, Vikram Reddy Kasarala

All Capstone Projects

Folate is an essential component for cell growth and cell division, playing a major role in DNA synthesis. It is common sense that the rapidly dividing cells synthesize more DNA, including cancer cells. Also, it was reported that cancer cells over express Folate receptors and this was the basis for our probe for cancer cells. We used long PEG biotin in conjugation with Folate. Previous studies in our group showed that the PEG could be used in the sensor to detect and capture cancer cells. The present study was aimed at evaluating the effect of Long PEG containing Folate based …

Evaluation And In Vitro Studies Of Folate Peg Biotin And Other Peg Agents, Christopher E. Zmudka

All Capstone Projects

Folate receptor alpha is a membrane-bound protein displaying high affinity for folic acid. This receptor is believed to serve as a receptor-mediated transport system of folic acid into cancer and cells associated with inflammation. Interesting, most normal cells in the body have little if no high affinity folate receptor alpha. Based on these attributes, folate based drug delivery, imaging systems, and diagnostic systems are in several stages of development worldwide.

Numerous methods have been explored in the literature in an attempt to detect low levels of free folate receptor and/or rare circulating cancer cells. In an attempt to further exploit …

Nanoparticles For Mercury Abatement, Sunil Krishna Thanikanti

All Capstone Projects

Mercury is considered to be a global contaminant. It does not break down in the environment and can build up in living organisms. Mercury can be carried long distances on wind currents, staying in the atmosphere for long periods of time, when in its vapor form. High mercury exposure results in permanent nervous system and kidney damage. Mercury exists in three different chemical forms: elemental, inorganic, and organic. The routes of exposure can be inhalation, ingestion, or skin contact. Vapor from liquid elemental mercury and methyl mercury are more easily absorbed than inorganic mercury salts and can, therefore, cause more …

Wound Healing And The Role Of Biomarkers And Biofilms, Mujtaba Khan

All Capstone Projects

An injury to the skin alters the integrity of underlying tissues and microcirculation and thus certainly culminates in a wound. Wound healing is a highly complex, dynamic, interactive and well regulated physiological process involving blood cells, extracellular matrix, parenchyma cells and soluble mediators. It starts with alteration in integrity of tissues and ends with the formation of scar. The process of wound healing is distinguished into Haemostasis, Inflammation, Proliferation and Remodeling. Various cells like platelets, neutrophils, macrophages, lymphocytes, angiocytes, keratinocytes, fibroblasts and factors like platelet derived growth factor, transforming growth factor, platelet derived epidermal growth factors, fibroblasts growth factor, albumin, …

Analytical Evaluation Of Imaging Agents, Vineela Chowdary Talluri

All Capstone Projects

The folate receptor has achieved great importance for use in targeted drug delivery and in vitro and in vivo diagnostic assays. The folate receptor (FR) is over expressed on several cancer cell types and activated macrophages, but exists in relatively low abundance on the surface of non-cancerous tissue and non inflammatory cells. This unique attribute is the hallmark of folate – targeted methodologies allowing the diagnostic agent and/or drug to be ferried to the specific disease sites while preventing “off target” effects in normal tissues. Although several folate-based dyes have been reported, simple and detailed synthetic and purification methods for …

Capture And Analysis Of Cells Using Magnetic Beads, Alexandro Dominguez

All Capstone Projects

Magnetic separation of cells and bacterium is a fascinating field of study. There are tremendous capabilities in separation, selectivity, and sensitivity. Magnetic separation reduces complex techniques, time consuming preparation, and complicated multistep methods of separation.The separation of cells, bacterium, and macromolecules can be extremely challenging. Fortunately, magnetically tagged cells, bacterium and macromolecules can be easily separated without great expertise. Antibody magnetic micro beads are specific to a cell, bacterium, or macromolecules. Separating a mixture can lead to a better, more accurate analysis of samples that can be crucial in the medical field, therapeutic drug delivery systems, and in some circumstances …

Effects Of Weathering On Aromatic Compounds In Beach Tars From The Deepwater Horizon Disaster, Gulf Of Mexico Coast, Usa, Michael A. Kruge

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

Operators aboard the Deepwater Horizon drilling platform lost control of the Macondo No. 1 well about 90 km southwest of the Louisiana coast on April 20, 2010, leading to a catastrophic release of ca. 550 Gg of crude oil over the next 86 days [1]. Oil from the spill soon found its way to nearby coastal areas, leaving tarry deposits on beaches and marshes. Oil was reported on the beach at Gulf Shores, Alabama (180 km northeast of the well) on June 5 and the relatively fresh sample discussed herein (GSA) was collected that same day. Oil reached the beach …

The Vinylguaiacol/Indole Or Vgi ("Veggie") Ratio: Assessing Relative Contributions Of Terrestrial And Aquatic Organic Matter To Sediments, Michael A. Kruge, Kevin K. Olsen, Jaroslaw W. Slusarczyk, Elaine Gomez

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

In studies of the organic matter (OM) fraction of marine, estuarine, fluvial, or lacustrine sediments, one of the most fundamental distinctions to be made is that between terrestrial and aquatic OM. To supplement the parameters commonly used for this purpose (e.g., C/N and stable isotope ratios), we proposed the Vinylguaiacol/Indole or VGI ("Veggie") ratio, defined as [vinylguaiacol / (indole + vinylguaiacol)] using data produced by analytical pyrolysis-gas chromatography/mass spectrometry of dried, homogenized sediment samples [1]. The ratio employs the peak areas of these two compounds on the mass chromatograms of their molecular ions (m/z 150 and 117, respectively). Major pyrolysis …

Fabrication Of Ito Micro-Pore Electrochemical Sensor And The Detection Of Exocytosis, Hui Zhao, Ling Li, Pin-Gang He, Yu-Zhi Fang

Journal of Electrochemistry

Exocytosis is one of the major means for cells to transmit messages. Amperometric detection of exocytosis is an important method in studying communication between cells. In this study a new type of ITO micro-pore electrochemical sensor was fabricated by means of ITO and UV light lithographic mask and was used in the detection of exocytosis with promising results. Compared with the conventional method, the ITO micro-pore sensor can not only replace the carbon fiber electrode, but be combined with fluorescent or chemiluminescent methods in detecting the physiological phenomena of cells.

Study On The Electrochemical Behaviors Of Gc Electrode Modified With Carbon Nanotube-Polyelectrolytes And Its Application For Rutin Detection, Liang Hua, Xia-Qin Wu, Rong Wang

Journal of Electrochemistry

The electrochemical behaviors of rutin and ascorbic acid at single-wall carbon nanotube and polyelectrolytes (dimethyl-diallylammonium chloride, PDDA) film modified glassy carbon electrode was investigated. The cyclic voltammetric results showed that electron transfer of rutin at PDDA/SWCNTs/GC modified electrode is an adsorption-controlled process. The separation of oxidation peak potentials of rutin and ascorbic acid was more than 200 mV. The rutin concentration in the presence of AA were detected by differential pulse voltammetry (DPV). The experimental results indicated that the PDDA/SWCNTs/GC modified electrode can be used for the detection of rutin in the presence of high concentration of AA. The DPV …

Development Of Dehydrogenase-Based Bioanode Using Poly(Phenosafranin)-Functionalized Swcnt Nanocomposites And Its Application To Ethanol Biosensor, S. Saleh Farhana, Okajima Takeyoshi, Lanqun Mao, Takeo Ohsaka

Journal of Electrochemistry

A New type of dehydrogenase-based amperometric ethanol biosensor was constructed using alcohol dehydrogenase (ADH) which was immobilized on the edge-plane pyrolytic graphite (EPPG) electrode modified with poly(phenosafranin)-functionalized single-walled carbon nanotube (PPS-SWCNT). The PPS-SWCNT modified EPPG electrode was prepared by electropolymerization of phenosafranin on the EPPG electrode which was previously coated with SWCNT. The performance of the ADH/PPS-SWCNT/EPPG electrode was evaluated using cyclic voltammetry and amperometry in the presence of ethanol. The fabricated ethanol biosensor provided a reasonable sensitivity of 2.0 μA cm–2 mM–1 and a low detection limit (36 μM) for the electrocatalytic oxidation of ethanol with a linear concentration …

Electrochemical Analysis Based On Molecular Recognition Of Nucleic Acids And Its Applications, Dian-Ming Zhou, Jian-Hui Jiang, Guo-Li Shen, Ru-Qin Yu

Journal of Electrochemistry

Nucleic acid as the carrier of genetic information and the functional molecules for molecular biology and bioanalytical chemistry has attracted increasing interest in electrochemical analysis. This review presents a brief outline of some electrochemical analytical assays based on molecular recognition of nucleic acids. Most of these methods are focused on the detection of nucleic acid sequence, genetic mutation and nucleic acids as functional molecules.

Preparations And Characters For Acetamiprid Of Molecular Imprinted Polymer Electrochemical Sensors, Bin Liu, Yong-Xing Huang, Hui-Ting Lian, Hong-Mei Wu

Journal of Electrochemistry

A novel molecularly imprinted membranes electrochemical sensor with good memory capacity to acetamiprid was developed. Based on electrodeposition technique, chitosan was deposited onto the surface of gold electrode as a functional polymer matrix along with aimed molecules acetamiprid and glutaraldehyde as a crosslinking agent. Cationic probe Ru(NH₃)₆Cl₃ was employed to indirectly investigate the electrochemical characteristics as well as the imprinted effect of the sensors. The results showed that the sensors had a specific recognition to acetamiprid compared to the structural similarity midacloprid and other pesticide. There is more sensitive response to acetamiprid at imprinted sensors …

Determination Of Hexamethylene Bisacetamide, An Antineoplastic Compound, In Mouse And Human Plasma By Lc–Ms/Ms, Kerri M. Smith, Wannarasmi Ketchart, Xiang Zhou, Monica M. Montano, Yan Xu

Chemistry Faculty Publications

Hexamethylene bisacetamide (HMBA) is a polar compound which has recently been discovered to have antineoplastic activity by up-regulating the expression of an endogenous antiproliferative breast cancer protein, HEXIM1 (hexamethylene bisacetamide inducible protein 1) in vivo. HMBA has been shown in the past to induce terminal differentiation in multiple leukemia types at a concentration of 2–5 mM, but its phase I and II clinical trials were largely unsuccessful due to serious side effects (notably, thrombocytopenia) with dose escalation. In this work, a sensitive and simple LC–MS/MS method for direct determination of HMBA in mouse and human plasma is described. Plasma samples …

Single-Step Biofriendly Synthesis Of Surface Modifiable, Near-Spherical Gold Nanoparticles For Applications In Biological Detection And Catalysis, Vivek D. Badwaik

Masters Theses & Specialist Projects

There is an increased interest in understanding the toxicity and rational design of gold nanoparticles (GNPs) for biomedical applications in recent years. Such efforts warrant reliable, viable, and biofriendly synthetic methodology for GNPs with homogeneous sizes and shapes, particularly sizes above 30 nm, which is currently challenging. In the present study, an environmentally benign, biofriendly, singlestep/ single-phase synthetic method using dextrose as a reducing and capping agent in a buffered aqueous solution at moderate temperature is introduced. The resulting GNPs are near-spherical, stable, catalytically active, place exchangeable, and water-soluble within the size range of 10-120 nm. The added advantage of …

Synthesis, Extraction, Dissolution, And Voltammetry Of F-Species In A Room Temperature Ionic Liquid Solvent, Wendy Jacqueline Pemberton

UNLV Theses, Dissertations, Professional Papers, and Capstones

Room temperature ionic liquids (RTILs) are salts that are liquids from as low as -96 °C to up to 100 °C. RTILs are of high interest in many fields of study because of their negligible vapor pressure, high electrochemical stability, high conductivity, and wide electrochemical windows. These diverse solvents have recently been used in organic synthesis, as extraction solvents, and as electrochemical solvents. It is as a direct result of the multifunctional capabilities of these RTIL solvents that they are examined in this work. The ability to probe the chemistry of lanthanides and actinides is based on the unique properties …

Equilibrium Speciation Of Select Lanthanides In The Presence Of Acidic Ligands In Homo- And Heterogeneous Solutions, Troy Robinson

UNLV Theses, Dissertations, Professional Papers, and Capstones

This dissertation explores lanthanide speciation in liquid solution systems related to separation schemes involving the acidic ligands: bis(2-ethylhexyl) phosphoric acid (HDEHP), lactate, and 8-hydroxyquinoline. Equilibrium speciation of neodymium (Nd³⁺ ), sodium (Na⁺ ), HDEHP, water, and lactate in the TALSPEAK liquid-liquid extraction system was explored under varied Nd³⁺ loading of HDEHP in the organic phase and through extraction from aqueous HCl and lactate media. System speciation was probed through vapor pressure osmometry, visible and Fourier Transform Infrared (FTIR) spectroscopy, ²² Na and ¹³ C labeled lactate radiotracer distribution measurements, Karl Fischer titrations, and equilibrium pH measurements. Distribution …

Miniature Mass Spectrometry: Rf Amplitude Control System Design, Matthew Allen Kirleis

Purdue Polytechnic Masters Theses

This thesis covers the methods used to construct and characterize a custom digital RF amplitude control system. Many types of mass spectrometers exist, but few have been miniaturized as much as the Mini instruments developed at Purdue University. The goal of this research was to improve upon an earlier amplitude control system consisting of analog circuits first implemented in the Mini 11.5 mass spectrometer developed at Purdue University.

A custom set of control and data acquisition electronics were developed for testing the digital and analog control systems in a Mini 11.5 mass spectrometer chassis. A MATLAB Simulink simulation was done …

Octaethyl-Nickel-Porphyrin Functionalized Silica For Fullerene Separation, Adriana Rodríguez^, Danisha M. Rivera, Luis Echegoyen*

COURI Symposium Abstracts, Summer 2011

No abstract provided.

Comparative Analysis Of Peak-Detection Techniques For Comprehensive Two-Dimensional Chromatography, Indu Latha, Stephen E. Reichenbach, Qingping Tao

School of Computing: Faculty Publications

Comprehensive two-dimensional gas chromatography (GC×GC) is a powerful technology for separating complex samples. The typical goal of GC×GC peak detection is to aggregate data points of analyte peaks based on their retention times and intensities. Two techniques commonly used for two-dimensional peak detection are the two-step algorithm and the watershed algorithm. A recent study [4] compared the performance of the two-step and watershed algorithms for GC×GC data with retention-time shifts in the second-column separations.In that analysis,the peak retention-time shifts were corrected while applying the two-step algorithm but the watershed algorithm was applied without shift correction. The results indicated that the …

Nanoencapsulated Drug-Carrying System For Photodynamic Antimicrobial Chemotherapy (Pact), Gopala Krishna Murthy Kalapala

All Capstone Projects

The purpose of this study is to develop nanoparticulate drug-carrying systems that are capable of directly delivering photodynamic antimicrobial agents to treat patients with chronic wounds. Chronic wounds are considered as a pandemic health problem. Approximately 1% to 2% of the population in developing countries has experienced a chronic wound during their lifetime. In the United State States, according to the American Academy of Dermatology, the expense of treating chronic wounds constitutes over half of the total cost for all skin diseases, which exceeds $10 billion annually. For the last decade extensive basic science and clinical research in chronic wounds …

Micro Bca Analysis Of Proteins, Anusha Chennupati

All Capstone Projects

The main objective of this project was to develop and validate methods for detection and analysis of proteins using a newly introduced microdrop plate reader equipped with a 16 well microdrop reader (2 uL sample volume). We used commercially available BSA, egg albumin, trypsinogen, Pepsin, β-lactoblobulin and lysozyme as out test moieties. Protein drop size, time, BCA reagent quantity, was assessed at various levels using a microdrop micro-BCA protocol (Pierce Chemical Company) with the appropriate controls (PBS blank) the method validated using the appropriate statistical and method parameters (i.e %RSD, and regression analysis of the standard curves). The micro method …

Novel Ruthenium Complexes As Photodynamic Therapeutic Agents, Sareen Kumar Kushangari

All Capstone Projects

This project reviews the literature of novel ruthenium c complexes in photodynamic drug therapy. (Abstract by OPUS staff)