Chemistry Commons^™

In Situ Pm-Irras Studies Of A Floating Bilayer Lipid Membrane At Au(111) Electrode Surface, Su Zhangfei, Kycia Annia, Jay Leitch J., Lipkowski Jacek

Journal of Electrochemistry

In situ Polarization modulation infrared reflection absorption spectroscopy (PM-IRRAS) was used to study the structure of a DMPC + cholesterol + GM1 floating bilayer lipid membrane (fBLM) at a Au(111) surface. 1-thio-beta-D-glucose (beta-Tg) was self-assembled onto the Au electrode to increase the overall hydrophilicity of the surface. The fBLM was deposited on the beta-Tg self-assembled monolayer (SAM) using a combination of Langmuir-Blodgett/Langmuir-Schaefer (LB/LS) techniques. The carbohydrate headgroups of the GM1 molecules were physically adsorbed to the beta-Tg SAM forming a water rich cushion between the fBLM and the modified gold substrate. The PM-IRRAS spectra indicate that the DMPC molecules within …

Electrochemical Detection Of Ammonia In Aqueous Solution Using Fluorescamine: A Comparison Of Fluorometric Versus Voltammetric Analysis, Panchompoo Janjira, G. Compton Richard

Journal of Electrochemistry

Fluorescamine is a non-fluorescent reagent widely used for the quantitative determination of primary amines by fluorescence spectroscopy as it reacts readily with primary amines to form a fluorescent product. In this work, a new sensitive voltammetric method for the detection of ammonia in aqueous solution by the reaction with fluorescamine has been developed. First, the electrochemical behaviour of fluorescamine in the absence and presence of ammonia was investigated in 0.1 mol L^-1 borate buffer solution (pH 9.0) by cyclic voltammetry using a glassy carbon (GC) electrode. As for fluorescamine itself, a well-defined irreversible oxidation peak could be observed at …

The Electrochemical Properties Of 1-Pyrenebutyric Acid/Graphene Composites And Their Application In Glucose Biosensors, Min Wang, Jiong Wang, Fengbin Wang, Xinghua Xia

Journal of Electrochemistry

The electrochemical properties of 1-pyrenebutyric acid/graphene composites (PBA/G) obtained by one-step synthesis via π-π stacking was investigated. The electrochemical impedance titration curve shows the surface charge changes as function of solution pH by using ferricyanide/ferrocyanide redox couple as the probe. An apparent pK_a value is estimated as 6.2 according to the impedance titration curve. In addition, a glucose biosensor was constructed by immobilizing glucose oxidase (GOD) on the surface of PBA/G via covalent interaction. This biosensor shows a linear response to glucose within the concentration up to 5 mmol L^-1 with a detection limit of 0.085 mmol L …

A Novel Microfluidic Enrichment Technique For Carbonylated Proteins, Bryant C. Hollins

Doctoral Dissertations

Proteins are the building blocks of cells in living organisms, and are composed of amino acids. The expression of proteins is regulated by the processes of transcription and translation. Proteins undergo post-translational modifications in order to dictate their role physiologically within a cell.

Not all post-translational modifications are beneficial for the protein or the cell. One type of post-translational modification, called carbonylation, irreversibly places a carbonyl group onto an amino acid residue, most commonly proline, lysine, arginine, and threonine. This modification can have severe consequences physiologically, including loss of solubility, loss of function, and protein aggregation.

Carbonylated proteins have commonly …

Method For Arsenic Detection In Mine Samples From The Upper Peninsula Of Michigan, Vinay Babu Yalamanchili

All Capstone Projects

Arsenic is the 20th abundant element in the earth crust. High concentrations of Arsenic is seen in mine operating countries which can affect public health and biological environment. This may reach to drinking water through ground or surface run-off water. Long term exposure to arsenic causes cancer of bladder, skin, and lungs. So detecting the amount of arsenic in soil and drinking has been an analytical challenge. Arsenic is found in variety of chemical forms in organic and inorganic compounds which results in chemical and physical interferences in the analysis. Graphite Furnace Atomic Absorption Spectroscopy (GFAAS) was used to measure …

Evaluation And In Vitro Studies Of Folate Peg Biotin And Other Peg Agents, Syed Zahid Hussain

All Capstone Projects

Folate is a member of vitamin B family and plays an essential role in cell survival by participating in the biosynthesis of nucleic and amino acids. Receptors folic acid are frequently over expressed on epithelial cancer cells. These receptors are believed to serve as a receptor-mediated transport system of folic acid into cancer cells and cells associated with inflammation. Interesting, most normal cells in the body have lower frequency of these receptors. Based on these attributes, folate based drug delivery, imaging systems, and diagnostic systems are in several stages of development worldwide.

In this current project, we have characterized the …

Literature Search On Using Dendrimer Nanoparticles As Drug Delivery Vehicles, Sivateja Kasaraneni

All Capstone Projects

The architectural design of dendrimers, multivalency, well-defined molecular weight and higher degree of branching differentiates them as unique and excellent nanocarriers in therapeutic applications such as drug delivery, gene transfection, tumor therapy, imaging and diagnostics. Nanoparticle drug-delivery systems are well known to increase the stability and selectivity of therapeutic agents. However immunogenicity, reticuloendothelial system uptake, drug leakage, cytotoxicity, hemolytic toxicity, poor aqueous solubility restrict the use of these drug delivery systems. These defects are overcame by surface engineering of the dendrimer molecule.

Drug molecule can be efficiently conjugated or encapsulated into the interior of the dendrimer or physically adsorbed onto …

Purification And Analysis Of Folate-Dye Conjugate, Sravya Mothe

All Capstone Projects

Folate receptor has achieved great importance for use in targeted drug delivery and in vitro and in vivo diagnostic assays. 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 these conjugates have …

Quality Assurance Plan Project For Copper Determination Using Flame Atomic Absorption Spectroscopy, Bharath Raparthi

All Capstone Projects

This study developed a method for determination of Copper by flame atomic absorption spectrometry (FAAS) from the soil samples and mine tailings using Perkin Elmer AAnalyst 800 atomic absorption spectrometer. A detailed procedure has been developed with a detection limit of 0.12 mg/L. In the recent decades, pollution from heavy metals has been increased. Copper is one of the trace metals that has a significant impact and carries risk to the human health. Calibration curve was established with working range 0.1 ppm to 5 ppm with a correlation coefficient of 0.9994. Over 50 environmental samples from the historic Copper mining …

Project Synthesis Of N Acetyl L Histidine Ethyl Amide And Standard Operating Procedure For Fractional Collector, Maneesha Jakkampudi

All Student Theses and Dissertations

Photo oxidation of proteins leads to the formation of cross links of the amino acids in the proteins and leads to induction of cataracts, photo aging of the skin and in the Photodynamic therapy of tumors.

Oxidation of proteins involves significant modification of particular amino acids residues with consequent photodynamic damage. Studies show that tryptophan, tyrosine and histidine side chains gives rise to semi stable peroxides on exposure to singlet oxygen these oxidized structures are studied with low temperature NMR. These peroxides or species derived from them have been postulated as key intermediates in subsequent reactions such as cross linking …

Quantitative Determination Of Acetylsalicyclic Acid And Acetaminophen By Q-Nmr (Quantitative Nuclear Magnetic Resonance) Technique, Gouthami Kanduri

All Student Theses and Dissertations

The pharmaceutical industry mainly uses chromatographic techniques such as High Performance Liquid Chromatography (HPLC) and Gas Chromatography (GC), to determine the quantity of the active ingredient and other material in the drugs. A large effort goes into developing methods using chromatography techniques. The method development and running HPLC and GC are time consuming. Methods need to be updated as the chromatographic columns and the instruments wear out. On the other hand, Nuclear Magnetic Resonance (NMR) technique is mainly used for qualitative analysis to determine the identity of compounds. However, Proton-NMR technique does provide quantitative information of compounds but to develop …

Electrochemical Sensing Of Guanine And Adenine Based On The Boron-Doped Carbon Nanotubes Modified Electrode, Ya-Lin Xia, Chun-Yan Deng, Juan Xiang

Journal of Electrochemistry

In this work, the boron-doped carbon nanotubes (BCNTs) modified glassy carbon (GC) electrode was simply fabricated, and the electrochemical oxidation behaviors of guanine and adenine at the BCNTs/GC electrode were investigated. Compared with the bare GC and CNTs/GC electrodes, the BCNTs-modified electrode exhibited extraordinary electrocatalytic activity towards the oxidations of guanine and adenine as indicated by the obvious increase in current responses. Moreover, the peak separation between guanine and adenine was large enough for their potential recognition in mixture without any separation or pretreatment. Therefore, the simultaneous determination of guanine and adenine was successfully achieved. The BCNTs/GC electrode showed high …

Electrochemical Immunosensor Based On Polycalconcarboxylic Acid Modified Electrode For The Determination Of Alpha-Fetoprotein, Xiao Lin, Shao-Huang Weng, Jian-Zhang Zhou, Ai-Lin Liu, Xin-Hua Lin, Yong-Ji You

Journal of Electrochemistry

A highly sensitive electrochemical immunosensor based on novel electropolymerized polycalconcarboxylic acid modified electrode (poly-CCA/GC) has been fabricated for the detection of alpha-fetoprotein (AFP). The differences of the poly-CCA/GC electrodes before and after the immobilization of AFP antibody were characterized via scanning electron microscopy (SEM) and electrochemical impedance spectroscopy (EIS). The immobilization of antibody/antigen/antibody-HRP sandwich was formed on the poly-CCA modified electrode for the determination of special AFP concentrations. The electrochemical signals generated from the HRP which catalyzed the TMB substrate were measured. Experiment results indicated that the developed immunosensor showed a good sensitivity and precision.

Phoenix Mars Mission Wet Chemistry Laboratory Detection Limit Of Martian Soil Oxidants, Lauren B. Petersen, Richard C. Quinn Dr.

STAR Program Research Presentations

This project utilizes the Microscopy, Electrochemistry, and Conductivity Analyzer (MECA) Wet Chemistry Laboratory Testbed (WCL), a payload component of the NASA Phoenix Mars Mission, to analyze Mars soil analogs to find the limits of detection for various compounds of interest- including peroxides, chlorates, sulfates, and other oxidants. When the Phoenix Rover landed in the northern plains of Mars in the summer of 2008, three soil samples were analyzed for soluble components. In this analysis, large amounts of perchlorate were detected. Now, we are relooking at the Phoenix data to see if it shows evidence of other oxidants. The electrochemical techniques …

Synthesis And Characterization Of Graphene Oxide, Jeremy A. Waddell, Arthur Cheng, Bin Chen

STAR Program Research Presentations

Graphene, a single atomic layer of sp² carbon atoms, has gotten a lot of attention from the scientific community because of its excellent mechanical and electronic properties. The mechanical exfoliation methods used to obtain graphene nanosheets are not effective for large scale manufacturing, so scalable synthesis approaches from structurally similar compounds are of great scientific interest. Graphene oxide is one such compound which is synthesized through the oxidation of graphite powder. The oxidation was performed using a modification of the previous experimental procedure. After synthesis, the powder was fabricated into graphene oxide films through vacuum filtration and transfer to …

Long-Range Ordered Carbon Clusters: A Crystalline Material With Amorphous Building Blocks, Lin Wang, Bingbing Liu, Hui Li, Wenge Yang, Yang Ding, Stanislav V. Sinogeikin, Yue Meng, Zhenxian Liu, Xiao Cheng Zeng, Wendy L. Mao

Xiao Cheng Zeng Publications

Solid-state materials can be categorized by their structures into crystalline (having periodic translation symmetry), amorphous (no periodic and orientational symmetry), and quasi-crystalline (having orientational but not periodic translation symmetry) phases. Hybridization of crystalline and amorphous structures at the atomic level has not been experimentally observed. We report the discovery of a long-range ordered material constructed from units of amorphous carbon clusters that was synthesized by compressing solvated fullerenes. Using x-ray diffraction, Raman spectroscopy, and quantum molecular dynamics simulation, we observed that, although carbon-60 cages were crushed and became amorphous, the solvent molecules remained intact, playing a crucial role in maintaining …

Reactions Of Methyl Perfluoroalkyl Ethers With Isopropyl Alcohol: Experimental And Theoretical Studies, Howard Knachel, Vladimir Benin, Chadwick Barklay, Janine C. Birkbeck, Billy D. Faubion, William E. Moddeman

Chemistry Faculty Publications

The reaction of an isomeric mixture of the methyl perfluoroalkyl ether, C4F9OCH3 (Novec-7100), in the presence of isopropyl alcohol (IPA) and/or water has been studied by measuring the rate of product formation using an ion-selective electrode (ISE) for fluoride ion, Karl Fisher coulometric titrations for water, and 1H and 19F NMR spectroscopy for product identification and rate studies. The results showed the methyl perfluoroalkyl ether to be very stable with products forming at the rate of ∼1 ppm per year at a laboratory temperature of 20 °C. Measurements over the temperature range of 6° to 100 °C were made on …

En Route Towards Α-Benzotriazoyl Nitroso Derivatives, Jean-Christophe M. Monbaliu, Lucas K. Beagle, Judit K. Beagle, Matthias Zeller, Christian V. Stevens, Alan R. Katritzky

Chemistry Faculty Publications

A new class of geminally-substituted nitroso compounds, i.e., α-benzotriazoyl nitroso derivatives, is presented. These compounds display a rather different behavior than other related nitroso compounds bearing a geminal electron-withdrawing group. An unexpected and spontaneous oxidation to the nitro analog is observed in solution.

Development And Validation Of An Lc–Ms/Ms Method For Pharmacokinetic Study Of Methoxyamine In Phase I Clinical Trial, Shuming Yang, Panayiotis Savvides, Lili Liu, Stanton L. Gerson, Yan Xu

Chemistry Faculty Publications

Methoxyamine (MX) is the first DNA base-excision-repair (BER) inhibitor evaluated in humans. This work described the development and validation of an LC–MS/MS method for quantitative determination of MX in human plasma. In this method, MX and its stable isotope methoxyl-d3-amine (MX-d3 as internal standard) were directly derivatized in human plasma with 4-(N,N-diethylamino)benzaldehyde. The derivatized MX and IS were extracted by methyl-tert-butyl ether, and separated isocratically on a Xterra C18 column (2.1 mm × 100 mm) using an aqueous mobile phase containing 45% acetonitrile and 0.4% formic acid at a flow rate of 0.200 ml/min. Quantitation of MX was carried out …

Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry Analysis Of Lower Pecos Rock Paints And Possible Pigment Sources, Jon Russ, Kaixuan Bu, Jeff Hamrick, James V. Cizdziel

Master of Science in Analytics (MSAN) Faculty Research

Chemical analyses of prehistoric rock paints from the Lower Pecos Region of southwestern Texas were undertaken using laser ablation-inductively coupled plasma-mass spectrometry. This technique allowed us to measure the chemical composition of the paint pigments with minimal interference from a natural rock coating that completely covers the ancient paints. We also analyzed samples representing potential sources of paint pigments, including iron-rich sandstones and quartzite from the study area and ten ochre samples from Arizona. Cluster analysis, principle component analysis and bivariate plots were used to compare the chemical compositions of the paint and pigment sources. The results indicate that limonite …

Integrated Approach For Low-Cost And Sensitive Multiplex Pathogen Detection On 3d Paper-Based Microfluidic Devices, Alejandra Valadez, Huan Hu, Xiujun James Li

COURI Symposium Abstracts, Summer 2012

Recently, pathogenic microorganisms have aroused wide public concern for their potential to cause serious diseases in humans, animals and agricultural crops. Although DNA microarrays are commonly used for pathogen detection, the approach is sophisticated, time-consuming and requires expensive equipment, limiting its application in resource-poor settings. Herein we present a novel, low-cost, paper-based microfluidic approach for multiplexed DNA detection of Giardia Lamblia, S. aureus, and Entamoeba, by “on-chip” isothermal DNA amplification and hybridization. Paper-based microfluidics offers a novel, sensitive and low-cost alternative for Point-of-Care Diagnostics for the Developing Countries. The project described utilizes Loop-mediated Isothermal Amplification (LAMP), a novel isothermal DNA …

Characterization Of Polymeric Phthalocyanine Nanoparticles Using Dynamic Light Scattering Laser, Satish Kumar Murarishetty

All Capstone Projects

The objective of this study is to use DLS (Dynamic Light Scattering) to analyze polymeric copper phthalocyanine nanoparticles (CuPcNPs). CuPcNPs are synthesized in order to facilitate drug penetration of bacterial biofilms for the treatment of chronic wounds. Microorganisms that reside inside the biofilms of chronic wounds are very resistant to any kind of treatment, even to the host’s own immune system. Therefore we have proposed an alternative method to destroy the microorganisms existing within the biofilms. Photodynamic anti-bacterial chemotherapy (PACT) has received much attention for the past decade due to the multi-drug resistant strands. PACT uses photons, a photosensitizer, and …

Nanoencapsulated Copper Pthalocyanine As Photodynamic Antimicrobial Chemotherapy, Prathima Arrabelly

All Capstone Projects

The growing resistance developed by microbes towards antimicrobial agents has driven our focus on developing alternative treatment modalities such as Photodynamic antimicrobial chemotherapy (PACT). It would be difficult for the microbes to develop resistance towards singlet oxygen generated during the PACT process. Photosensitizers are the vehicles of the transfer and translation of light energy into a type II chemical reaction (singlet oxygen generation) in photodynamic antimicrobial chemotherapy. PACT is proposed as a potential, low cost approach to treatment of locally occurring infection.

Photodynamic inactivation (PDI) of Escherichia coli and Staphylococcus aureus has been studied in cultures treated with photoactivated copper …

Nano Encapsulated Drug Delivery For Biofilms, Arunakanth Chavala

All Capstone Projects

Biofilms are now considered ubiquitous in the natural world. Bacterial biofilms have been observed to be extremely heterogeneous, both structurally and with regard to the physiology of the bacterial cells within them. The prevailing conceptual model depicts bacterial biofilms as being made up of microcolonies, which serve as the basic unit of the greater biofilm structure. A major concern with this approach is the frequently observed development of resistance to antimicrobial compounds. A number of elements in the process of biofilm formation have been studied as targets for novel drug delivery technologies. The present study aimed to penetrate biofilm by …

Analysis Of Barbiturates By Gc/Ms, Hplc And Chemical Ionization, Deepthi Ravipati

All Capstone Projects

Barbiturates are derivatives of barbituric acid. They act as central nervous depressants. These drugs are frequently used as sedatives or anesthetics. It is a simple and reproducible method for the analysis of barbiturates.

Usage of these drugs is increased in recent days and the analysis of barbiturates by GC/MS is very fast. As they are used as sedatives their usage has been increased to relieve the stress. But the over usage of these drugs may lead to death. Different barbiturates like phenobarbital, pentobarbital can be analyzed by their molecular weights. Because of the over usage of the drugs the interest …

Nanoparticlated Drug Delivery System For Vitreous Humor, Kartheek K. Suragoni

All Capstone Projects

The purpose of this study is to develop a unique nanoparticulated system that has the capability of providing sustained drug delivery into the eyes. In ophthalmic preparations, poor ocular drug delivery of ocular dosage form is due to the production of tears and impermeability through corneal epithelium. The usage of liposomes in ophthalmic disorders shows promising results in ocular drug delivery. Liposomes are bilayered, microscopic vesicles surrounded by the aqueous compartments. Liposomes have the ability to encapsulate both hydrophilic and hydrophobic drugs. This unique property of liposomes helps in delivering the drug at specific site. This invention involves three major …

Spectroscopic Characterization Of Dissolved Organic Matter: Insights Into Composition, Photochemical Transformation And Carbon Cycling, John Robert Helms

Chemistry & Biochemistry Theses & Dissertations

This dissertation explores processes affecting the composition of dissolved organic matter (DOM) and how DOM composition changes in sunlit surface waters and in the dark interior ocean. Simulated solar irradiations were used to investigate the impact of photochemistry on terrestrial waters and deep ocean DOM. The photochemically mediated processes observed in Dismal Swamp samples included (i) light induced flocculation of up to 12% of the organic matter and 84% of the dissolved iron originally present; (ii) 74-88% mineralization of dissolved organic carbon (DOC) and 95-99% bleaching of chromophoric DOM (CDOM) during 110 days of irradiation; and (iii) nearly complete loss …

Nih Shift Literature Search, Nicole Owens

All Capstone Projects

The NIH shift is a chemical shift of substituents in aromatic hydroxylation reactions. The substituents that undergo this shift are hydrogen, halogens, acyl and alkyl groups. It is an important aspect that is a requirement in the hydroxylation of aromatic compounds by monooxygenase enzymes.

The NIH shift or the National Institute of health shift gets its name from the founders of this mechanism. The National Institute of Health was the first to observe this phenomenon in there studies and are the first to report this chemical shift.

Simple Analysis And Possible Solutions Of The Unusual Interfacial Reactions In Li-S Batteries, Xin-Ping Ai, Yu-Liang Cao, Han-Xi Yang

Journal of Electrochemistry

Rechargeable Li-S batteries are a promising power source with realizable energy densities several times higher than current Li-ion batteries. However, the capacity utilization and cycling stability of the existing Li-S technologies are still insufficient for battery applications. The causes for the electrochemical instability of this redox system arise probably from the changes in the surface structures and electrochemical microenvironments of the Li anode and sulfur cathode during charge-discharge reactions, which includes the frustrated electron transfer in the sulfur-carbon interface, the dissoluble diffusion of the polysulfide intermediates, and the shuttle reaction inbetween the sulfur and Li electrodes. To deal with these …

Detection Of Pml/Rarî± Fusion Gene Using Gold Nanopaticles Modified Electrode By Chronocoulometry, Li-Man Wang, Li-Qing Lin, Shao-Huang Weng, Xin-Hua Lin, Yuan-Zhong Chen

Journal of Electrochemistry

A gold nanoparticles modified electrode was prepared by electrodeposition at constant potential. The sulfydryl modified probe was immobilized onto surface of gold nanoparticles via Au-S covalent bond and hybridized with complementary target DNA sequences, then the DNA sensor was fabricated for the detection of PML/RARα fusion gene by chronocoulometry in acute promyelocytic leukemia (APL). Scanning electron microscopy (SEM) and electrochemical impedance spectroscopy (EIS) were used to characterize the surface morphology of gold nanoparticles and the constructing process of sensor. With hexaammineruthenium(Ⅲ) chloride (RuHex) as a novel electrochemical indicator, the chronocoulometric DNA biosensor was employed to monitor artificial APL PML/RARα fusion …