Analytical Chemistry Commons^™

The Pilot Application Of Electrochemical Impedance Spectroscopy On Dynamic Proton Exchange Membrane Fuel Cell, Jian-Wei Guo, Jian-Long Wang

Journal of Electrochemistry

By analyzing Electrochemical Impedance Spectroscopy (EIS) in applications of dynamic proton exchange membrane fuel cell (PEMFC), bottlenecks which restrict EIS tool development have been pointed out in this paper. Though the high-frequency resistance in EIS is largely accepted as cell inner-resistance, this can only be applied for cell with low current. The low-frequency resistance is difficult to be realized due to its relation with mass transfer. Furthermore, the improved Randles equivalent circuits are built up preliminarily, thus, penetrating into studies for mass transfer reaction, cell operation/degeneration, and high temperature fuel cell. Inspiringly, EIS is becoming an analyzing tool for stack …

Stabilized, Hybrid Solid-State Photocatalysts For Water Purification: Preparation, Properties And Performance Under Visible Light Irradiation, Karpagavalli Ramji

Seton Hall University Dissertations and Theses (ETDs)

Stabilized heterogeneous photocatalysts that use only solar light and air have been prepared and successfully employed to decontaminate water from organic pollutants. Organic dye pollutants present, for example in textile effluents, are one of the major sources of water pollution owing to their limited biodegradability, toxicity and potential carcinogenic risks. Before certifying water for public consumption, reuse in industries or for discharge in surface water the organic pollutants must be degraded, an effort that is energy intensive and currently requires complex methodologies. We report solid-state photocatalysts that use only visible light and air to treat wastewater. Perfluoroalkyl perfluoro-substituted zinc phthalocyanine …

Electropolymerization Of Polyaniline In The Presence Of Ferricyanide: Electrochemical, Spectroscopic And Gravimetric Studies, Lucas Marinelli

Master's Theses

In this work, ferricyanide-doped polyaniline (PANI) is electropolymerized by constant current and cyclic voltammetry (CV) measurements with simultaneous monitoring of mass changes using electrochemical quartz crystal microbalance (eQCM). Raman spectroscopy, Fourier transform infrared spectroscopy and CV measurements confirm the incorporation of the ferricyanide into the film and indicate modified electrical conductivity. UV-Vis absorbance spectroscopy and Raman spectroscopy confirm the conducting ‘emeraldine-salt’ state and confirm the presence of polarons, i.e. charge carriers.

The addition of ferricyanide during electropolymerization of the PANI film results in an increase of polymerization rate as confirmed using eQCM. A decrease in counter ion ingress/egress and an …

Detection And Melting Of Surface-Bound Dna Using A Purely Electrochemical Approach, Denny Ho

Master's Theses

In this thesis, we demonstrate an electrochemical approach for monitoring the electric-field induced melting of surface-bound double-stranded DNA. The electrochemical routine involves repeated chronoamperometry pulses to melt the duplex and square wave voltammetry to monitor the extent of melting. We utilize a scanning potential and constant potential technique to generate melting curves and access the stability and kinetics of the DNA duplexes. Our method uses a mixed monolayer of thiol-modified DNA oligomers and mercaptohexanol on gold electrodes, are subsequently incubated with target DNA covalently modified with electroactive methylene blue. Under room temperature, 10 mM Tris, and optimized electrochemical parameters, DNA …

The Investigation Of The Chlorine Initiated Oxidation Of 2-Phenylethanol And Stability Of Superalkali Lithium Substituted Silyls., Adam Otten

Master's Theses

This thesis investigates the combustion potential of 2-phenylethanol and the superalkali properties of small lithium substituted silicon compounds. All combustion experiments were performed at the Advanced Light Source of Lawrence Berkeley National Laboratory at the Chemical Dynamics Beamline 9.0.2. The chlorine initiated oxidation of 2PE was investigated at 298 and 550 K using a multiplex photoionization mass spectrometer, coupled with the tunable vacuum ultraviolet radiation. Reaction products were identified using kinetic time traces and photoionization spectra.

Additionally, the stability of small superalkali silicon-lithium compounds has also been investigated. All structures and energetics were calculated using the CBS-QB3 composite method.

The …

The Regional Distribution And Molecular Interactions Of Phospholipids And Glucose In Mammalian Vitreous Humors., Abigail Nicole Schnepf

Electronic Theses and Dissertations

The vitreous humor (VH) is located in between the lens and the retina. It is composed of 98% water, hyaluronan (HA), collagen, proteins, phospholipids (PLs), and other metabolites. With aging, the VH undergoes liquefaction, a process that causes the gel-like structure of the VH to turn into a liquid and can lead to serious ocular diseases, including retinal detachment, vitreal detachment, and macular hole formation. The liquefaction process is expedited in diabetic VHs. This project focuses on understanding the molecular changes that lead to liquefaction and the reasons for which this process is accelerated with diabetes. Matrix-assisted laser desorption ionization/mass …

Relative Permittivity As A Function Of Co-Solvent And Impedance Spectroscopy For Quantifying Anions In Solution, Yahya Sami Alseiha

Electronic Theses and Dissertations

This work measured relative permittivity from 15.0 to 55.0 °C of aqueous solutions containing acetone or tetrahydrofuran using a BI 870 dielectric meter. A cubic polynomial fit resulted in coefficients for calculating permittivity as a function of temperature and mole fraction. Literature values for other co-solvent system resulted in similar polynomial coefficients. Using BI 870, permittivity measurements of ionic solutions were not possible because of high conductivity. A simple method using impedance spectroscopy measured these solutions. Impedance decreases with increasing temperature and decreases with increasing ionic strength. Due to the temperature dependence of impedance, all measurements were at 25.0 °C. …

Elevated Calcium Levels In Kentucky Lake: A Possible Emerging Problem With An Invasive Species, Adam T. Martin

Posters-at-the-Capitol

Zebra mussels (Dreissena polymorpha) are an exotic and invasive mollusk that have spread extensively through various rivers and lakes in the United States. These mussels are notorious for their “biofouling” capabilities costing billions of dollars in their removal from industrial, public, and power plant water supply lines. While having been present in the Tennessee River drainage with occasional small reproducing populations since the early 1990s, zebra mussels were never abundant or widespread. In 2017, high densities were found on structures and solid substrates throughout the lower portion of Kentucky Lake. Calcium is one of the essential elements that contributes …

Consumption Profiles Of Illicit And Neuropsychiatric Drugs In Urban And Rural Communities In Kentucky Using Sewage Epidemiology, Tara Croft, Katelyn Foppe, Rhiannon Huffines, Bikram Subedi

Posters-at-the-Capitol

The drug overdose deaths in the USA increased by ~20% from 2015 to 2016 to the total >63,600 drug overdose deaths in 2016. Kentucky is among the highest rate of drug overdose death states in the USA. The current estimates of the prevalence of substance abuse are based on the self-reported surveys, overdose/toxicological reports, and drug-related crime statistics. Survey-based conventional approaches are not only cost and time-intensive but also underestimate the actual consumption of drugs. As “wastewater never lie,” the drug residues in raw wastewater collected from the centralized wastewater treatment plants were utilized to determine the consumption rate of …

Mass Spectrometry And Nuclear Magnetic Resonance In The Chemometric Analysis Of Cellular Metabolism, Eli Riekeberg

Department of Chemistry: Dissertations, Theses, and Student Research

The development and awareness of Machine Learning and “big data” has led to a growing interest in applying these methods to bioanalytical research. Methods such as Mass Spectrometry (MS), and Nuclear Magnetic Resonance (NMR) can now obtain tens of thousands to millions of data points from a single sample, due to fundamental instrumental advances and ever-increasing resolution. Simple pairwise comparisons on datasets of this magnitude can obfuscate more complex underlying trends, and does a disservice to the richness of information contained within. This necessitates the need for multivariate approaches that can more fully take advantage of the complexity of these …

Molecular Level Interactions And Transformations Of Natural Organic Matter Within The Environment, Benjamin J. Haywood

LSU Doctoral Dissertations

This work was done in order to deepen the understanding of interactions occurring during sorption of anthropogenic organic compounds and dissolved organic matter (DOM) onto soil. As well as the transformation DOM undergoes during the sorption process and the overall transformation OM undergoes in the environment. This was achieved through the use of a “bottom-up” synthetic investigation, “top-down” natural system study, and a combination of these approaches.

The “bottom-up” approach, discussed in Chapter 2, involved the synthesis of a modular multi-tiered engineered soil surrogate (ESS) designed to mimic OM and general trends identified in the literature that impacts sorption behavior. …

‘Cassette’-Ises (In Situ Enzymatic Screening) Identifies Complementary Chiral Scaffolds For Hydrolytic Kinetic Resolution Across A Range Of Epoxides, Sangeeta Dey, Douglas R. Powell, Chunhua Hu, David B. Berkowitz

Department of Chemistry: Faculty Publications

‘Cassette’-ISES (In Situ Enzymatic Screening) Identifies Complementary Chiral Scaffolds for Hydrolytic Kinetic Resolution Across a Range of Epoxides

A new ‘Cassette’-In Situ Enzymatic Screen (ISES) for combinatorial catalysis is introduced. This allows the experimentalist to obtain an information-rich readout, in real time, providing an estimate of the sense and magnitude of enantioselectivity across more than one substrate. In its first iteration, the screen identified Co^III-salen catalysts with β-pinene- and α-naphthylalanine-derived chiral scaffolds with broad, yet complementary, substrate specificities.

Guanidinium Compounds, Stephen Dimagno, Bao Hu

Department of Chemistry: Faculty Publications

The present application provides , inter alia , chemical com pounds useful as synthesis intermediates , said compounds comprising one or more guanidinium moieties and a hyper valent iodine atom . Methods for making these compounds are also provided.

Synthesis Of Keggin Polyoxometalates Modified Carbon Paste Electrode As A Sensor For Dopamine Detection, Peng-Fei Dong, Na Li, Hai-Yan Zhao, Min Cui, Cong Zhang, Ju-Jie Ren, Xue-Ping Ji

Journal of Electrochemistry

Polyoxometalates, a class of anionic clusters with structure diversity and size variability, make them very attractive in many fields such as electrochemistry, catalysis and medicine. The Co(C₁₅N₆H₁₂)₂[PW₁₂O₃₈]·5H₂O(Co[PW₁₂O₃₈]) modified carbon paste electrode was prepared in this work, and its electrochemical performances as the sensor for dopamine detection were characterized with electrochemical impedance spectroscopy, cyclic voltammetry and differential pulse voltammetry. The preparation conditions and test conditions were optimized respectively. Under the optimized conditions, the POMs modified carbon paste electrode exhibited good selectivity and sensitivity …

Influence Of Salinity, Sunlight, And Sediment On The Toxicity Of Pesticides In Three Non-Target Organisms, Emily Noelle Vebrosky

LSU Doctoral Dissertations

Pesticides used in the United States must undergo registration by the United States Environmental Protection Agency (USEPA), after a multitude of analyses ranging from environmental fate to aquatic toxicological impacts to human risk exposure. Testing varies for each chemical, some requiring more testing than others. In many cases, environmental factors are restricted in the analysis of chemical behavior and organismal testing is limited to larvae. Many pesticides are formulated to breakdown in the environment by means of photolysis, hydrolysis, or oxidation, either to ensure low-persistence, limited transport, or to form the active ingredient (pro-pesticides). Environmental influences on chemical behaviors include …

Photocatalytic Activity: Experimental Features To Report In Heterogeneous Photocatalysis, Md. Ariful Hoque, Marcelo I. Guzman

Chemistry Faculty Publications

Heterogeneous photocatalysis is a prominent area of research with major applications in solar energy conversion, air pollution mitigation, and removal of contaminants from water. A large number of scientific papers related to the photocatalysis field and its environmental applications are published in different journals specializing in materials and nanomaterials. However, many problems exist in the conception of papers by authors unfamiliar with standard characterization methods of photocatalysts as well as with the procedures needed to determine photocatalytic activities based on the determination of “apparent quantum efficiencies” within a wavelength interval or “apparent quantum yields” in the case of using monochromatic …

Nanoparticles And Their Use In Cancer Imaging, Prevention And Treatment, George Gray

Chemistry & Biochemistry Student Projects

No abstract provided.

Tomatine And Furocoumarins: Toxins In Commonly Consumed Plants, Julia Noonan

Chemistry & Biochemistry Student Projects

No abstract provided.

Data On Ion Composition And X-Ray Diffraction Patterns Of Biosolids From Wastewater Treatment Plants In Lufkin And Nacogdoches, Texas, Usa, Kefa Karimu Onchoke, Christopher M. Franclemont, Paul W. Weatherford

Faculty Publications

The data presented in this article is related to the research article entitled, “Structural Characterization and Evaluation of Municipal Wastewater Sludge (Biosolids) from two Rural Wastewater Treatment Plants in East Texas, USA”, Onchoke, KK, Franclemont, C.M., Spectrochim. Acta A, In press[1]. The XRD profiles and composition of biosolids from wastewater treatment plant is presented. This study describes the composition of XRD crystalline phase patterns of the wastewater sludge. After the removal of the Ka2 peaks the d-spacing and hkl values were determined. In addition, the ion chromatographic profile of the seven anions (NO₃^-, NO_{2 …}

Developing A New Sensing Technology For Double-Stranded Dna Detection Utilizing Engineered Zinc Finger Proteins And Nanomaterials, Dat Thinh Ha

Masters Theses & Specialist Projects

A specific double-stranded DNA sensing system is of great interest for diagnostic and other biomedical applications. Zinc finger domains, which recognize double-stranded DNA, can be engineered to form custom DNA-binding proteins for recognition of specific DNA sequences. As a proof of concept, a sequence-enabled reassembly of TEM-1 β- lactamase system (SEER-LAC) was previously demonstrated to develop zinc finger protein (ZFP) arrays for the detection of a double-stranded bacterial DNA sequence. Here, we implemented the SEER-LAC system to demonstrate the direct detection of pathogenspecific DNA sequences present in E. coli O157:H7 on the lab-on-a chip. ZFPs customdesigned to detect shiga toxin …

An Overview Of Dynamic Heterogeneous Oxidations In The Troposphere, Elizabeth A. Pillar-Little, Marcelo I. Guzman

Chemistry Faculty Publications

Due to the adverse effect of atmospheric aerosols on public health and their ability to affect climate, extensive research has been undertaken in recent decades to understand their sources and sinks, as well as to study their physical and chemical properties. Atmospheric aerosols are important players in the Earth’s radiative budget, affecting incoming and outgoing solar radiation through absorption and scattering by direct and indirect means. While the cooling properties of pure inorganic aerosols are relatively well understood, the impact of organic aerosols on the radiative budget is unclear. Additionally, organic aerosols are transformed through chemical reactions during atmospheric transport. …

High Resolution Imaging Of Single Nanoparticles And Two-Dimensional Nano-Material By Scanning Electrochemical Microscopy, Tong Sun

Dissertations, Theses, and Capstone Projects

Electrochemistry at nanostructured interfaces is of significant current interest. Metal nanoparticles (NPs) and two-dimensional semiconductor nanomaterial are particularly important because of their applications in catalysis, energy conversion and storage, sensors, and medicine. Electrocatalytic processes at such nanostructured interfaces are essential for the generation of hydrogen and other types of fuels and photochemical energy conversion. Nanoscale electrochemical experiments require the fabrication and characterization of nanometer-size electrochemical probes. The main advantages of the nanoprobes include very fast mass-transfer rate, high signal-to-noise ratio and extremely fine spatial resolution of electrochemical imaging. During my Ph.D. research, nanoscale disk-type platinum electrochemical probes were developed for …

Characterization And Quantification Of Covalent Modification Of Proteins Using Mass Spectrometry, Pratikkumar N. Rathod

Dissertations, Theses, and Capstone Projects

Identification and characterization of various post-translational modifications of protein is a key to understanding many unknown cellular processes. In the last few decades, mass spectrometry has evolved as an essential and effective analytical tool for qualitative and quantitative analysis of proteins. In this research, we have developed a novel MALDI-MS² based quantification method for Desmosine and Isodesmosine, which served as cross-linking amino acids of elastin, in order to measure the elastin degradation in the body. This is the first quantification method that not only illustrates the potential of MALDI-Ion Trap MS², but also improvement over the current …

Acetylcholinesterase Biosensor Platform Based On Bp2000 For The Detection Of Carbaryl, Ming-Han Zhang, Jun-Qiao Jiang, Jun-Jie Ge, Wei Xing

Journal of Electrochemistry

With the purpose of providing a new method for carbaryl (a pesticide) detection, on the basis of the principle that acetylcholinesterase (AChE) activity can be restrained by carbaryl, an AChE biosensor platform based on BP2000 (as a fixation) was constructed by dropping method. As a result, it revealed that AChE immobilized on BP2000 maintained its catalytic activity for acetylcholine (ATCl), and due to the introduction of the BP2000 material, the effective electrochemical surface area of the modified electrode was enlarged. In addition, the electrochemical oxidation at the modified electrode occurred at low potential (0.630 V) accompanied by proton transmission. The …

Radioiodinated Compounds, Stephen Dimagno, Bao Hu

Department of Chemistry: Faculty Publications

This disclosure relates to reagents and methods useful in the synthesis of aryl iodines ,for example , in the preparation of iodine labeled radiotracers . The reagents and methods provided herein may be used to access a broad range of compounds , including aromatic compounds , heteroaromatic compounds , amino acids , nucleotides , and synthetic com pounds .

Determination Of Polar Solvents By Static Headspace Extraction – Gas Chromatography (She-Gc), Michael Sithersingh

Seton Hall University Dissertations and Theses (ETDs)

ABSTRACT

The term “headspace” is defined as the vapor that forms above or around a liquid or solid sample in a closed container. Usually, the vapor is above the liquid or solid at the top of the container, hence the term headspace. Headspace sampling is a method for separating volatile materials that may be extracted from a more solid sample matrix and then analyzed using gas chromatography. Headspace extraction refers to the collection and analysis of the vapor phase in the container. The Static Headspace Extraction – Gas Chromatography (SHE-GC) technique has been used since the early days of Gas …

Enhanced Acidity Of Acetic And Pyruvic Acids On The Surface Of Water, Alexis J. Eugene, Elizabeth A. Pillar, Agustín J. Colussi, Marcelo I. Guzman

Chemistry Faculty Publications

Understanding the acid–base behavior of carboxylic acids on aqueous interfaces is a fundamental issue in nature. Surface processes involving carboxylic acids such as acetic and pyruvic acids play roles in (1) the transport of nutrients through cell membranes, (2) the cycling of metabolites relevant to the origin of life, and (3) the photooxidative processing of biogenic and anthropogenic emissions in aerosols and atmospheric waters. Here, we report that 50% of gaseous acetic acid and pyruvic acid molecules transfer a proton to the surface of water at pH 2.8 and 1.8 units lower than their respective acidity constants pK_{a …}

Tof-Sims Analysis Of Plant Seed Interactions With Plant Growth-Promoting Bacteria, Tammy Pheuphong, Rachel Komorek, Xiao-Ying Yu

STAR Program Research Presentations

The use of time-of-flight secondary ion mass spectrometry (ToF-SIMS) in plant biology is a relatively unexplored and quickly developing field. The majority of research in plant SIMS involves the application of ToF-SIMS to study dried wood tissues, and only a handful of studies apply SIMS on plant stems, roots, and/or seeds. Our project provides a brief description and review of previous work using SIMS on plant stems, roots, and/or seeds, along with an emphasis on the sample preparation in each study. Additionally, the use of Brachypodium distachyon (Brachypodium) as a model system for research on grasses has also become more …

Manganese Oxide/Hemin-Functionalized Graphene As A Platform For Peroxynitrite Sensing, Haitham F. Kalil, Shaimaa Maher, Tiyash Bose, Mekki Bayachou

Chemistry Faculty Publications

Peroxynitrite (ONOO−, PON) is a powerful oxidizing agent generated in vivo by the diffusion-limited reaction of nitric oxide (NO) and superoxide (O₂˙⁻) radicals. Under oxidative stress, cumulated peroxynitrite levels are associated with chronic inflammatory disorders and other pathophysiological conditions. The accurate detection of peroxynitrite in biological systems is important, not only to understand the genesis and development of diseases, but also to explore and design potential therapeutics. Herein, a manganese oxide/hemin-modified graphene interface is explored as a platform for peroxynitrite amperometric detection. Hemin-functionalized reduced graphene oxide was further modified with manganese oxide nanoparticles to provide a …

Novel Relative Spontaneous Ignition Temperature Determination Using Carbon Dioxide Onset With Sta/Ir, Antonio David Trevino

Electronic Theses and Dissertations

Simultaneous thermal analysis, coupled with infrared spectroscopy (STA/IR), was utilized to monitor the evolution of gaseous products during the thermal degradation of samples from Triadica sebifera (Chinese tallow), Ligustrum sinense (Chinese privet), and Ilex vomitoria (yaupon) plants. Identification of carbon dioxide was successful with a spectral match of 90.2 percent and further used in the determination of relative spontaneous ignition temperature, or RSIT. The RSIT value during the growing season for Chinese tallow, Chinese tallow stem, Chinese privet, and Yaupon were 208.4°C, 250.3°C, 210.1°C, and 232.3°C respectively. During the dormant seasons, the values for Chinese tallow stem, Chinese privet, and …