Analytical Chemistry Commons^™

Method Development For The Quantification Of Critically Valuable Elements In Permian Basin Produced Waters, Carley Oliver

Open Access Theses & Dissertations

Produced waters (PW) are a major byproduct of the oil and gas industrial hydraulic fracturing processes that create a major waste disposal issue with a need for disposal, treatment, and reuse method developments. The current primary disposal method is subsurface injection, which can lead to high pressures in the subsurface. PWs are often highly saline from mineral leaching due to long residence in subsurface reservoirs. According to the USGS National Minerals Information Center, bromine, calcium chloride, iodine, lithium, magnesium, and sodium chloride have been found in and extracted from these domestic subsurface brines, suggesting that there may be other economically …

Electrocatalytic Reduction Of Hydrogen Peroxide At Paraffin-Sealed Nitrogen-Doped Carbon Fiber Ultramicroelectrodes, Yakubu Gausu Mohammed

Electronic Theses and Dissertations

Compared to unmodified carbons and even some metal materials, nitrogen-doped carbons have been found to exhibit better performance for reducing oxygen-oxygen bonds, a key step in electroreduction of both O₂ (an important reaction in energy applications) and H₂O₂ (an important reaction in sensing and biosensing). Previous studies from our lab revealed that thermal decomposition of urea in the presence of carbon fiber (CF) results in N-doped that exhibited good electrocatalytic properties for H₂O₂ reduction. However, previous methods of sealing ultramicroelectrodes (UMEs) made from N-doped CF using laser heating of borosilicate capillaries and epoxy …

Assessing The Reactivity Of Amino Acids To Chlorination Using Capillary Electrophoresis, Pedro De Allende

Electronic Theses, Projects, and Dissertations

Amino acids (AA) are ubiquitous in wastewater systems. One of the most popular wastewater treatments is chlorination which is effective at eradicating bacteria and overall treating the wastewater, but it can also produce disinfection by-products (DBPs). Certain DBPs have been classified as Class B Carcinogens to humans and are therefore highly regulated and monitored. Past studies have shown that natural organic matter (NOM), specifically amino acids, can be precursors to DBPs if chlorinated to the correct dose. This thesis project explored AA chlorination's mechanism(s) to understand further which products arise. In particular, the investigation detailed which steps of the mechanism …

Characterizing Gsk3Β Interaction And Kinetics Via Isothermal Titration Calorimetry, W A Bhagya De Silva

UNLV Theses, Dissertations, Professional Papers, and Capstones

Glycogen synthase kinase 3β (GSK3β) is a multifunctional serine/threonine kinase involved in several key signaling pathways, including glycogen metabolism, WNT/β-catenin, and Hedgehog signaling. Hyperactivity of GSK3β has been linked to Alzheimer’s disease, bipolar disorder, type II diabetes, and some cancers. Therefore, GSK3β is of interest as a target for therapeutics. Lithium ion (Li+) is a classical inhibitor of GSK3β. Structurally similar beryllium ion (Be2+) is ~1000-fold more potent. Lithium and beryllium have demonstrated pathway-specific and cell type-specific inhibition of GSK3β, prompting an investigation into the inhibitory mechanisms and thermodynamic characteristics of the metal-enzyme interaction.Isothermal titration calorimetry (ITC) is a label-free …

Assessment Of Tce And Chiral Pcb Dechlorination Rate, Congener Diversity, And Enantioselectivity In Town Creek, Sc, Usa Sediment Microcosms, Catherine P. Sumner

All Dissertations

Polychlorinated biphenyls (PCBs) and trichloroethene (TCE) are ubiquitous contaminants and are recognized as persistent organic pollutants due to their extreme chemical stability. PCBs were manufactured by chlorinating biphenyls that created 209 congeners with various structures, of which 19 are chiral and can exist as a pair of stable atropisomers. PCBs have been known to cause developmental and neurological toxicity in humans and wildlife; they can act as endocrine disrupters, carcinogens, and teratogens. Sangamo Weston Inc. was an industrial plant located near Town Creek in Pickens Country, South Carolina, that manufactured capacitors and used Aroclors 1016 and 1254 as dialectic fluids …

Computational Models That Exploit Spatial, Temporal, And Voltage-Current Relationships In The Electrochemical Generation-Collection Of Redox-Active Molecules, Miguel Angel Abrego Tello

Graduate Theses and Dissertations

The numerical studies in this dissertation explore the application of redox cycling, an advanced electrochemical technique, for analyzing bioelectrochemical systems with a particular focus on small-volume samples and involves electrodes that can be activated to oxidize and reduce, separated by varying distances and featuring different geometries. The redox cycling approach facilitates the spatio-temporal interrogation of kinetics, mass transport, and the quantification and identification of chemical systems. We optimize a previously fabricated neural probe design on an SU-8 substrate, featuring coplanar arrays of nine microband electrodes suited for in vivo applications. Through comprehensive in situ and in silico redox cycling studies …

First Announcement Of 76th Annual Meeting Of The International Society Of Electrochemistry, International Society Of Electrochemistry (Ise)

Journal of Electrochemistry

No abstract provided.

Tribocorrosion And Metal Release From Austenitic Stainless Steels 304 And 201 In Simulated Cassava Food Contact, Robert Addai, Temitope E. Olowoyo, Thalia E. Standish, Jeffrey Daniel Henderson, Ubong Eduok, Yolanda Hedberg

Chemistry Publications

Cassava is the third most significant calorie source in the tropics. Its processing has changed from traditional methods to stainless steel processing machines. This study investigated the influence of cassava on metal release from two common stainless steels, ASTM 304 and 201, with and without friction, and on tribocorrosion (multianalytically) of 304. Cassava was relatively corrosive and hindered repassivation of the surface oxide of stainless steel, but it also acted as a lubricant against mechanical friction. The combined action of friction and cassava caused a significant increase in iron, chromium, nickel, and manganese release from the stainless steels (30–35- fold …

The Analysis Of Artificially Flavored Coffees, Hannah Knights

Longwood Senior Thesis Proposal

This project aims to determine the molecular components that give artificially flavored coffees their advertised flavor. Much work has been conducted to determine various characteristics such as antioxidant properties, phenolic compounds, flavors, and aromas found in natural coffees. In addition, there is ample literature on the results of sensory tests for a variety of commercial coffees. However, not much work has been conducted to determine the compounds found in artificially flavored coffees that give rise to their distinctive aroma and flavor. This is, perhaps, due to the proprietary nature of the flavoring process employed by commercial producers. The goal of …

Establishment Of Protocols To Measure Near-Ir(Nir) Surface-Enhanced Raman Scattering (Sers) Signals Of Nir Dye, Justin B. Ramsey

Forensic Science Master's Projects

Biomedical imaging techniques are crucial for early disease diagnostics, particularly for life-threatening conditions. However, traditional methods have inherent limitations, such as restricted spatial resolution and potential risks associated with repeated exposure to ionizing radiation. Near-infrared (NIR) surface-enhanced Raman spectroscopy (SERS) presents a promising alternative due to its minimal risks and potential for high-resolution biomedical imaging. A key challenge in NIR-SERS biomedical imaging is the development of biocompatible, nontoxic SERS substrates that can be safely introduced into the human body, targeting specific cells and tissues effectively.

NIR-SERS substrates typically consist of gold nanoparticles (AuNPs) modified with biorecognition elements and reporter molecules, …

Effects Of The Biochar Of Senna Tora On The Soil Fertility Of Misau Farmlands, Bauchi State, Northern Nigeria, Ozoilo Onyeka Calistus, Umar Faruk Hassan, Auwal Adamu Mahmoud, Haruna Baba, Hamza Badamasi, Hannatu Akanang

Journal of Bioresource Management

The use of biochar as an amendment to the soil is attracting the scientific community's attention because of its cost-effectiveness, eco-friendliness, and its promising success in increasing the fertility of the soil and crop yield. In the present study, the effects of biochar from Senna tora applications on soil characteristics and the availability of micronutrients in Misau, Bauchi State, Nigeria, were explored. A completely randomized approach was adopted and duplicated three times, with reference soil (no biochar), 30-day, and 60-day biochar treatments. The biochar was removed at the end of the treatment, and soil samples from the various treatments were …

In Situ Diffuse Reflectance Spectroelectrochemistry Of Cathode Materials In Lithium-Ion Batteries, Lu-Lu Chen, Hao-Ran Li, Wei-Yi Liu, Wei Wang

Journal of Electrochemistry

Developing in situ spectroelectrochemistry methods, which can provide detailed information about species transformation during electrochemical reactions, is very important for studying electrode reaction mechanisms and improving battery performance. Studying real-time changes in the surface of electrode materials during normal operation can be an effective way to assess and optimize the practical performance of electrode materials, thus, in situ and in operando characterization techniques are particularly important. However, batteries are hard to be studied by in situ characterization measurements due to their hermetically sealed shells, and there is still much room for battery characterizations. In this work, a specially designed battery …

Electrochemical Detection Of Glucose Using A Prussian Blue Modified Electrodes Combined With Glucose Encapsulated Within A Xerogel, Daniel Baker, Sarah Davis, Drew Budner

Journal of the South Carolina Academy of Science

Recent literature reports examples of electrochemical biosensor systems that have been developed based upon on the encapsulation of enzymes and metal nanoparticles into a xerogel. These systems have been utilized for the detection of biologically important compounds, such as glucose. These reports on these systems have found acceptable detection limits and linear ranges. At the same time, Prussian blue modified electrodes have been shown to have better operating parameters than metal electrodes for the detection of hydrogen peroxide. In this work, a biosensor system is described that incorporates the encapsulation of glucose oxidize within a xerogel combined with electrochemical detection …

Implementing 1.5 Millimeter Internal Diameter Columns And A Portable Capillary Column Instrument Into Monoclonal Antibody Analytical Workflows, Benjamin Libert

Theses and Dissertations

Using 1.5 mm inner diameter (i.d.) columns to bridge the gap between routinely used 2.1 mm i.d. columns and capillary bore columns allows for a sequential but significant increase in performance without the need for specialized equipment associated with very low dispersion liquid chromatography (LC) systems. These 1.5 mm i.d. columns balance an increase in sensitivity compared to 2.1 mm i.d. columns (theoretically doubling the time-domain peak area in mass sensitive detectors for the same mass load), while mitigating the efficiency losses due to extra-column dispersion effects that are commonly observed with 1.0 mm i.d. columns. Here, the use of …

Turning Trash Into Treasure: Using Old Optical Spectrometers As Learning Tools In Instrumental Analysis, Ken Overway

Chemistry Faculty Scholarship

Chemical instrumentation is complex and expensive. When an instrument becomes nonfunctional, its pedagogical value remains despite its inability to make measurements. This work presents a laboratory experiment which gives new purpose to old optical spectrometers while building knowledge and confidence of students in their understanding of chemical instrumentation. Students are given a guided tour of spectroscopic instruments, starting from the simplest, and are asked to identify components and draw the optical path of each instrument. Allowing students to look inside of decommissioned instruments gives students a chance to see the differences and similarities of optical spectrometers while reinforcing the form …

Heavy Metals Implications To Sediment Microbiome And Coral Response To Arsenic Dosing, Dimitrios G. Giarikos, Amy Hirons, Jose V. Lopez, Abigail Renegar, Jason Gershman

SECLER Data

No abstract provided.

Production Of The Siderophore Lysochelin In Rich Media Through Maltose-Promoted High-Density Growth Of Lysobacter Sp. 3655, Fang Zhang, Jia Liu, Lin Jiang, Yongbiao Zheng, Lingjun Yu, Liangcheng Du

Department of Chemistry: Faculty Publications

Siderophores are produced by bacteria in iron-restricted conditions. However, we found maltose could induce the biosynthesis of the siderophore lysochelin in Lysobacter sp. 3655 in rich media that are not compatible with siderophore production. Maltose markedly promoted cell growth, with over 300% increase in cell density (OD₆₀₀) when LB medium was added with maltose (LBM). While lysochelin was not detectable when OD₆₀₀ in LBM was below 5.0, the siderophore was clearly produced when OD₆₀₀ reached 7.5 and dramatically increased when OD₆₀₀ was 15.0. Coincidently, the transcription of lysochelin biosynthesis genes was remarkably enhanced following the …

Hatt-Flow: Hierarchical Attention-Flow Mechanism For Group-Activity Scene Graph Generation In Videos, Naga Venkata Sai Raviteja Chappa, Pha Nguyen, Thi Hoang Ngan Le, Page Daniel Dobbs, Khoa Luu

Electrical Engineering and Computer Science Faculty Publications and Presentations

Group-activity scene graph (GASG) generation is a challenging task in computer vision, aiming to anticipate and describe relationships between subjects and objects in video sequences. Traditional video scene graph generation (VidSGG) methods focus on retrospective analysis, limiting their predictive capabilities. To enrich the scene-understanding capabilities, we introduced a GASG dataset extending the JRDB dataset with nuanced annotations involving appearance, interaction, position, relationship, and situation attributes. This work also introduces an innovative approach, a Hierarchical Attention–Flow (HAtt-Flow) mechanism, rooted in flow network theory to enhance GASG performance. Flow–attention incorporates flow conservation principles, fostering competition …

Molecular-Level Studies Of Nanopatterned Biomolecules With Atomic Force Microscopy, Ashley R. Walker

LSU Doctoral Dissertations

Atomic force microscopy (AFM) is an analytical technique in which a tipped probe is gently scanned across the surface in a raster pattern to generate digital images of a sample at the nanoscale. The AFM instrument has three general operational modes, which are contact, non-contact and tapping-mode, that can be used to examine materials at the atomic level. Single-molecular details of biological molecules and other soft organic materials can be captured with minimal denaturation in either ambient or liquid environments when using tapping-mode AFM. In tapping-mode, the probe is driven to oscillate vertically while the tip is scanned across the …

The Investigation Of The Reaction Of 2,3-Dimethylfuran With O(³P) And The Estimate Of The Photoionization Cross Section Of C-Cl And Absolute Photoionization Cross Sections Of Chlorinated Organic Compounds, Yilan Lori Chen

Master's Theses

The work presented in this thesis focuses on gas-phase reactions, which are fundamental for reducing greenhouse gas emissions and mitigating climate change. The experiments are performed at the Advanced Light Source (ALS) of Lawrence Berkeley National Laboratory, where there is a time-of-flight mass spectrometer coupled with tunable synchrotron radiation at Beamline 9.0.2 to collect high-quality data.

Chapter 1 details the background and purpose of each project, along with an overview of the origins of synchrotron radiation and time-of-flight mass spectrometry. The adaptation of biofuels is a way to minimize carbon emission and air pollutants, so research surrounding the reaction dynamics …