Analytical Chemistry Commons^™

Graphene-Like Secondary-Laser-Etched Polyimide Film Decorated With CuXO Nanocomposites: A Novel Electrode Substrate For Non-Enzymatic Glucose Sensors, Wan-Lin Dai, Zhi-Wei Lu, Jian-Shan Ye

Journal of Electrochemistry

In this work, a novel electrode substrate with graphene-like surface and Cu_xO nanocomposites derived from secondary-laser-etched polyimide (SLEPI) film was synthesized and applied in non-enzymatic glucose detection for the first time. Characterizations indicate that the as-prepared SLEPI/Cu_xO film electrode (SLEPI/Cu_xO-FE) possessed huge surface area, plentiful active sites and excellent electrocatalytic performance. The obtained sensor exhibited the high sensitivity and selectivity for glucose determination with a linear range of 0.05 mmol·L^-1 to 3 mmol·L^-1 and a detection limit of 1.72 μmol·L^-1 (S/N=3), which provides a simple, flexible and low-cost electrochemical sensor for …

Heavy Metal Detection With Bismuth Film Electrode, Jen Olivero, Iain Laprade, Gabby Servito

Creative Activity and Research Day - CARD

The purpose of this project is to extend the application of stripping square-wave voltammetry to allow for the detection of various heavy metals in water samples, to include lead, cadmium, and zinc contaminants. Glassy carbon bismuth film electrodes proved to be more reliable than screen printed carbon electrodes for detection of heavy metals. Parameters were optimized to allow for the quantification of lead, zinc, and cadmium simultaneously in tap water along with an unknown Fromm water sample. Cadmium and thallium were found to be present at the same potential on the voltammogram; this prevented simultaneous detection of both metals. Bismuth …

The Effects Of Ph On The Kinetics Of The Follow-Up Reaction Of Dopamine O-Quinone, Cyril Fong, Ziming Dong

Creative Activity and Research Day - CARD

The electrochemical studies of dopamine have been conducted for many years due to dopamine’s importance as a neurotransmitter and its function in daily life for individuals. Dopamine undergoes electrochemical redox reactions in which the different products can be detected by cyclic voltammetry.³ The focus of the experiments was to determine the pH range at which dopamine o-quinone would undergo cyclization as well as the relationship between the rate of cyclization as pH in the physiological range. The measurements were taken using a gold working electrode vs. a Ag/AgCl (1 M KCl) reference electrode. It was observed that the peaks …

Effect Of Salt Concentration On Electrochemical Detection Of Dna, Ziming Dong, Eddie Madrigal, Ryan West Dr.

Creative Activity and Research Day - CARD

Electrochemical approaches for biological sensing offer the potential advantages of facile sample preparation, fast response times, ease of parallel and multiplexed measurements, and the possibility of miniaturization (of sample sizes, electrodes, and associated electronics). All of these factors contribute towards the feasibility of electrochemical methods in biological sensing and analysis. This potential has already been achieved with the commercialization of blood glucose meters, which often rely on an electrochemical transduction mechanism. We have previously demonstrated the ability to electrochemically detect and differentiate complementary and mismatched DNA using our method of melting DNA duplexes at electrified gold surfaces, i.e. e-melting. Recently, …

Quantitative Analysis Of Iron In Beer Using Cloud Point Extraction, Joshua Rempfer

Student Scholar Showcase

Determination of Iron concentration in Apocalypse Ale beer using a preconcentration method coupled with UV-Vis spectroscopy. Samples will be cross checked with MP-AES to ensure precise and accurate results.

Elemental Analysis Of Legacy Sediments At College Lake, Amelia Dalton

Student Scholar Showcase

College Lake is a large reservoir located on the campus of the University of Lynchburg. College Lake’s ecosystem has degraded over the years due to the buildup of sediment, nutrients, and raw sewage. Increased urbanization in the area has also most likely contributed to the contaminants present within the system. Because of flooding issues during the summer of 2018, Lynchburg CIty officials drained College Lake, which caused sediment to be released downstream. To better understand the transport of heavy metals in the sediments released from College Lake, sediment core samples were taken from College Lake, Hollins Mill Park, and Sandusky …

Mobilization Of Calcium Across Mineralized Tissues In Yellow Perch, Perca Flavescens, Taylor Bopp

Student Scholar Showcase

Bones in many higher teleost fish, such as percids and centrarchids, lack osteocytes that function as both chemo- and mechano-sensors, and thus, are not actively involved in homeostasis of blood calcium level. Nonetheless, the vertebrae of yellow perch, Perca flavescens (P. flavescens), living in darker and low calcium (Ca) water, have demonstrated adaptive modeling and remodeling of vertebrae to be more mineralized and thus enhance transmission of the axial muscle torque into the thrust force for the C-start predator escape behavior. The prey-predator interaction is expected to occur at closer range between prey fish and predator fish in …

A Chemical In Filter Paper Interferes With Trail Following Behavior In The Termite Reticulitermes Hesperus (Banks), Kathryn Vest

Student Scholar Showcase

Termites follow chemical trails. In previous experiments we dissolved and diluted chemicals in acetone to test if they elicited trail following. Each trail was a straight line across the arena drawn with 10 µl using a glass capillary (Microcaps). We noticed a minor but stable response to trails laid with pure acetone. The response could be caused by contaminated acetone or by a chemical in the filter paper (Watman #5) that lined our arena (petri dish, 10cm diameter). We could confirm that the termites respond to acetone alone. Soxkhlet extraction for 8 hours removed the signal from the filter paper. …

Hour-Level Resolution On Consumption Pattern Of Substance Abuse, Jarrett Mauk, Rhiannon Huffines, Brittney Nelson, Tara Croft, Bikram Subedi

Scholars Week

Conventional survey-based approaches of determining the consumption statistics of drugs in communities are suffered from non-response biases, and typically underestimate the actual consumption. Time and cost-intensive conventional approaches, therefore, can’t be utilized to determine high-resolution temporal variability in drug consumption. In this study, the temporal trend of consumption of 10 illicit and 26 prescribed neuropsychiatric drugs was determined at hour-level resolution utilizing wastewater-based epidemiology. The hourly composite raw wastewater (every 10 minutes) samples were collected for three consecutive days in a typical week (total of 72 samples), analyzed for target drug residues using UPLC-MS/MS, and back-calculated the consumption rate of …

Uncertainties Treatment For Wastewater-Based Epidemiological Estimation Of The Consumption Of Illicit And Prescribed Neuropsychiatric Drugs In Two Urban Communities In Kentucky Using Ammonium Normalized Population And Monte Carlo Simulation, Rhinannon Huffines, Tara Croft, Manoj Pathak, Bikram Subedi

Scholars Week

The conventional estimation of the prevalence of substance use in a community based on self-reported surveys typically underestimates the actual consumption. Drug’s residues in raw wastewater collected from the centralized wastewater treatment plants were utilized – Wastewater-Based Epidemiology (WBE) – to determine the consumption rate of illicit and prescribed neuropsychiatric residues in two urban communities in eastern Kentucky and two rural communities in western Kentucky. The ammonical nitrogen content in raw wastewater samples was used to minimize the uncertainty associated with the population dynamicity. Uncertainties associated with the several WBE parameters to back-calculate the consumption rate of drugs such as …

Drug Improvement And Design Involving G-Protein Coupled Receptors, Gabriel Saliba

Chemistry & Biochemistry Student Projects

No abstract provided.

A Chemical Overview Of Opioid Receptors And Their Agonists, Noah Kuszak

Chemistry & Biochemistry Student Projects

This work is a brief overview of the three main opioid receptors and some current research of the ways we can change the agonists and how they affect the opioid receptor pathway.

Dentin Biomodification Potency Of Proanthocyanidins, David J. Ryker

Chemistry & Biochemistry Student Projects

No abstract provided.

Quantification Of Tylosin Antibiotics In Cattle Waste, Appala Keerthi

Masters Theses & Specialist Projects

Antibiotics are used as prophylactic agents to promote growth and for treating infections in animals. However, the irrational use of antibiotics in livestock management is a significant cause of the development of antibioticresistant genes in the environment. Each year 2 million people suffer from the infections caused by bacteria which are resistant to antibiotics and 23,000 of these people are estimated to die because of antibiotic resistance. New drugs are continually coming into the market but are at the risk of developing resistance. Thus, there is a need for the development of analytical methods which can be used to monitor …

Monitoring Transverse Relaxation Times Of Kerosene-Adulterated Diesel Using Low-Field Nuclear Magnetic Resonance Spectroscopy, Tristen Rumbaugh

Experiential Learning Projects

Time-domain nuclear magnetic resonance spectroscopy (TD-NMR) and low-field nuclear magnetic resonance spectroscopy (LF-NMR) are different techniques that vary in the range of magnetic field strengths that they use, which is a determining factor for the type of analysis that can be done. In this study, LF-NMR was used to perform a time-domain analysis of petroleum products, diesel and kerosene. This is a type of analysis which is typically performed using TD-NMR. Diesel and kerosene are two petroleum products that have different characteristics such as viscosity, boiling point, and hydrocarbon length. Diluting, or adulterating, diesel fuels with kerosene is a common …

A Dual Nanostructured Approach To Sers Amenable To Large-Scale Production, Kory Brian Castro

Chemistry & Biochemistry Theses & Dissertations

A SERS device was made using a dual-nanostructured surface comprised of silver nanoparticle and silver nanowires. The ability of each nanostructure to produce a uniform surface was characterized and the surface-enhanced Raman scattering (SERS) response of the resulting surfaces were examined using the reporter molecule 4-aminothiolphenol (ATP) and a 638 nm excitation laser.

A synthetic method was developed to produce silver nanowires with lengths of ~20 μm and diameters of ~100 nm with a narrow size distribution. The method utilized a simple, one-pot synthesis that is amenable to large-scale production. A selective precipitation method was used to the isolate the …

A Quantitative Lc-Ms/Ms Method For Determination Of A Small Molecule Agonist Of Epha2 In Mouse Plasma And Brain Tissue, Bo Zhong, Yaxin Li, Nethrie Idippily, Aaron Petty, Bin Su Ph.D., Bingcheng Wang

Chemistry Faculty Publications

Compound 27 {1, 12‐bis[4‐(4‐amino‐6,7‐dimethoxyquinazolin‐2‐yl)piperazin‐1‐yl]dodecane‐1,12‐dione} is a novel small molecule agonist of EphA2 receptor tyrosine kinase. It showed much improved activity for the activation of EphA2 receptor compared with the parental compound doxazosin. To support further pharmacological and toxicological studies of the compound, a method using liquid chromatography and electrospray ionization tandem mass spectrometry (LC–MS/MS) has been developed for the quantification of this compound. Liquid–liquid extraction was used to extract the compound from mouse plasma and brain tissue homogenate. Reverse‐phase chromatography with gradient elution was performed to separate compound 27 from the endogenous molecules in the matrix, followed by …

Development Of Nanomaterial Supports For The Study Of Affinity-Based Analytes Using Ultra-Thin Layer Chromatography, Allegra Pekarek

Department of Chemistry: Dissertations, Theses, and Student Research

Ultra-thin layer chromatography (UTLC) is a growing field in analytical separations. UTLC is a branch of planar and liquid chromatography that is related to thin layer chromatography. The main advantage of UTLC compared to other techniques is it uses much less material, allowing for faster and more sensitive separations to take place. The UTLC devices fabricated in this project used either silicon oxide or silicon nanopillars deposited on a glass slide using glancing angle deposition (GLAD). Even a thin layer of these nanopillars deposited on a glass slide provide a large surface area for the analyte to be separated. GLAD …

Analysis Of Drug–Protein Interactions During Diabetes By High-Performance Affinity Chromatography, Pingyang Tao

Department of Chemistry: Dissertations, Theses, and Student Research

High-performance affinity chromatography (HPAC) is a type of liquid chromatography in which solutes are separated based on their binding to a stationary phase that is a biologically-related agent. Sulfonylurea drugs have significant binding to proteins in blood, with most of this binding is believed to occur with human serum albumin (HSA). HSA is known to be modified as a result of the high serum levels of glucose that is present during diabetes, which may also alter the function of HSA as a binding agent for many drugs in circulation. Some modifications of HSA that can occur during diabetes involves early …

Study Of The Effects Of Silver Ions And Silver Nanoparticles On Embryonic Development, Martha Sharisha Johnson

Biomedical Sciences Theses & Dissertations

This dissertation focuses on the study of the toxicity of metal nanoparticles (NPs) and their ions on the development of zebrafish embryos, aiming to understand unique biological effects of NPs and ions, and design new in vivo assays to characterize the toxicity of these metal NPs and metal ions. Currently, the underlying molecular mechanisms of biological effects of nanomaterials are partially understood. Some studies assume that the toxic effects of NPs can be attributed to the release of their ions. We investigate the effects of silver NPs (Ag NPs) and silver ions (Ag+ ions) on the embryonic development of zebrafish …

An Improved Synthesis Of Adefovir And Related Analogues, Timothy P. O'Sullivan, Et Al

Physical Sciences Publications

An improved synthesis of the antiviral drug adefovir is presented. Problems associated with current routes to adefovir include capricious yields and a reliance on problematic reagents and solvents, such as magnesium tert-butoxide and DMF, to achieve high conversions to the target. A systematic study within our laboratory led to the identification of an iodide reagent which affords higher yields than previous approaches and allows for reactions to be conducted up to 10 g in scale under milder conditions. The use of a novel tetrabutylammonium salt of adenine facilitates alkylations in solvents other than DMF. Additionally, we have investigated how …

The Effects Of Reactant Concentration And Air Flow Rate In The Consumption Of Dissolved O2 During The Photochemistry Of Aqueous Pyruvic Acid, Alexis J. Eugene, Marcelo I. Guzman

Chemistry Faculty Publications

The sunlight photochemistry of the organic chromophore pyruvic acid (PA) in water generates ketyl and acetyl radicals that contribute to the production and processing of atmospheric aerosols. The photochemical mechanism is highly sensitive to dissolved oxygen content, [O₂(aq)], among other environmental conditions. Thus, herein we investigate the photolysis (λ ≥ 305 nm) of 10–200 mM PA at pH 1.0 in water covering the relevant range 0 ≤ [O₂(aq)] ≤ 1.3 mM. The rapid consumption of dissolved oxygen by the intermediate photolytic radicals is monitored in real time with a dissolved oxygen electrode. …

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 …

Infrared Laser Ablation For Biomolecule Sampling, Kelin Wang

LSU Doctoral Dissertations

In this research, an infrared laser at a wavelength of 3 µm was used to ablate material from tissue sections for biomolecule analysis. Pulsed infrared (IR) irradiation of tissue with a focused laser beam efficiently removed biomolecules, such as proteins, enzymes, DNA, and RNA from tissue sections for further analysis. In a proteomics project, matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) was used to determine regions of interest (ROI) for laser ablation. The matrix was then washed off. By overlaying the MSI generated heat-map, the section was sampled using IR laser ablation and custom stage-control software. Two ROI were selected …

Tracking Decitabine Incorporation Into Malignant Myeloid Cell Dna In Vitro And In Vivo By Lc-Ms/Ms With Enzymatic Digestion, Sujatha Chilakala, Ye Feng, Lan Li, Reda Mahfouz, Ebrahem Quteba, Yogen Saunthararajah, Yan Xu

Chemistry Faculty Publications

The DNA hypomethylating agents decitabine and 5-azacytidine are the only two drugs approved for treatment of all subtypes of the myeloid malignancy myelodysplastic syndromes (MDS). The key to drug activity is incorporation into target cell DNA, however, a practical method to measure this incorporation is un-available. Here, we report a sensitive and specific LC-MS/MS method to simultaneously measure decitabine incorporation and DNA hypomethylation. A stable heavy isotope of 2'-deoxycytidine was used as an internal standard and one-step multi-enzyme digestion was used to release the DNA bound drug. Enzyme-released decitabine along with other mononucleosides were separated by a reverse-phase C-18 column …

Lake Sediment Analysis At Heron Haven Nature Center, Erik Lato

UNO Student Research and Creative Activity Fair

Understanding the chemical composition of a wetland sanctuary lakebed can help us understand how recent developments may have changed the chemical composition. Due to recent dredging by the U.S. Army Corps of Engineers and previous research on water composition at Heron Haven, the goal of this project was to determine the chemical composition as a function of sediment depth. The concentration of seven different metals and nutrients were analyzed in terms of depth. The aluminum, iron, and phosphate concentrations had no real discernible concentration change as a function of depth. There is some hint of a steady increase of manganese …

Voc Emission Factors From 3d Printers - Abs (Acrylonitrile-Butadiene-Styrene) Type Filaments, Dean Lay

LSU Master's Theses

Acrylonitrile-butadiene-styrene (ABS) is a polymer that is widely used in many plastic products and is receiving new attention due to its use as a filament for fused deposition modelling (FDM) 3D printers. It has been shown to emit potentially dangerous volatile organic compounds (VOCs) when heated at temperatures used in the 3D printing process. Many new products are becoming available that contain various additives to the polymer matrix, which have an unknown effect on the emission profiles and rates. In this study a method is developed using a modified system for thermal diagnostic studies (STDS) to evaluate VOC emission from …

Student-Faculty Collaborative Research Grant Report, Megan Bestwick

Post-Grant Reports

Mitochondria are essential organelles in most eukaryotic cells because of their role in metabolism and the production of ATP by the oxidative phosphorylation (OXPHOS) pathway, as well as other key cellular processes. Metal cofactors, such as copper (Cu) and iron (Fe), are incorporated into OXPHOS protein complexes of yeast located within the inner membrane of the mitochondria. Misincorporation or modulation of these available metals in mitochondrial enzymes leads to the production of reactive oxygen species (ROS). ROS are reactive molecules containing oxygen such as peroxides, superoxide, and hydroxyl radicals. Yeast are a good model for studying aging and the effect …

Slips-Teng: Robust Triboelectric Nanogenerator With Optical And Charge Transparency Using A Slippery Interface, Wanghuai Xu, Xiaofeng Zhou, Chonglei Hao, Huanxi Zheng, Yuan Liu, Xiantong Yan, Zhengbao Yang, Michael Leung, Xiao Cheng Zeng, Ronald X. Xu, Zuankai Wang

Xiao Cheng Zeng Publications

Energy harvesting devices that prosper in harsh environments are highly demanded in a wide range of applications ranging from wearable and biomedical devices to self-powered and intelligent systems. Particularly, over the past several years, the innovation of triboelectric nanogenerators (TENGs) that efficiently convert ambient kinetic energy of water droplets or wave power to electricity has received growing attention. One of the main bottlenecks for the practical implications of such devices originates from the fast degradation of the physiochemical properties of interfacial materials under harsh environments. To overcome these challenges, here we report the design of a novel slippery lubricant-impregnated porous …

Potential Degradation Of Hexabromocyclododecane (Hbcdd) In Sediments: Stereoisomer Specific Reaction Of Hbcdd With Reduced Sulfur Species Or Fe(Ii) Bound To Iron Oxides, Xianmiao Zhang

Dissertations, Theses, and Capstone Projects

The individual degradation rates of the three dominant stereoisomers (alpha, beta, gamma) of hexabromocyclododecane (HBCDD) with bisulfide and polysulfides were investigated at pH 9-10 in methanol/water solutions at two different temperatures (25 °C and 40 °C). alpha-HBCDD reacts significantly slower than beta-HBCDD and gamma-HBCDD. It was also observed that the reaction of HBCDD with polysulfides is faster than with bisulfide. For the reaction of HBCDD with bisulfide, the experiments were performed in 20% water/80% methanol, 50% water/50% methanol and 80% water/20% methanol at 40 °C. It was determined that the solvent polarity affects the reaction and the second-order rate constants …