Analytical Chemistry Commons^™

Advancement In Electrochemical Generation-Collection: Snapshot Redox Cycling Voltammetry For Rapid Analysis At Chip-Based, Individually Addressable Microband Electrode Arrays, Blake Aleck Sterling

Graduate Theses and Dissertations

Snapshot redox cycling voltammetry (Snapshot RCV) is introduced as a rapid electrochemical technique that reconstructs the current-potential profile of a redox active species using a microband electrode array. By simultaneously biasing individual generator electrodes alternating in the array to different voltages across the analyte’s potential range while individually holding collector electrodes at a reversing potential, “spatial” voltammetry is achieved in as little as 1 s with the temporal speed of chronoamperometry, rapidly capturing the steady-state redox cycling (RC) profiles. During RC (a mode of generation-collection), the analyte is oxidized (or reduced) at generator electrodes and converted back at neighboring collector …

Designing Surface-Induced Entatic States In Copper Complexes For Tunable Reactivity, Rachel Kiser

Senior Theses

Copper catalysts play an important role in electrocatalytic oxidation reactions due to their redox flexibility and relative abundance compared to noble metal catalysts. In biological systems, copper metalloenzymes often achieve enhanced reactivity through an entatic state. Entasis is described as an active site or metal center being constrained to a geometric and electronic state, minimizing primary sphere reorganization energy and achieving higher rates of electron transfer.  This study investigates whether entasis can be achieved in synthetic molecular catalysts by immobilizing Cu(I) complexes onto metal oxide surfaces. Two Cu(I) complexes bearing carboxylate-functionalized ligands were examined both in homogeneous solution and when …

Determination Of Trace Amounts Of Pb2+ And Cu2+ Ions In The Ohio River With Anodic Stripping Voltammetry And Flame Atomic Absorption Spectroscopy To Test Water Contamination From Factories., Eliana Purcell

The Cardinal Edge

In this project, water near factories in Rubbertown, Louisville, KY were tested to see if a significant enough amount of waste is deposited in the Ohio River that the concentrations of Pb2+ and Cu2+ exceed the maximum contaminant levels the World Health Organization (WHO) and the United States Environmental Protection Agency (EPA) have set in place. Waste from industrial factories may contain contaminants that have negative effects on aquatic ecosystems and even human health, so two potentially harmful metal ions were tested. The concentration of Cu2+ in water samples was detected through flame atomic absorption spectroscopy (FAAS), and the concentration …

Molecular Design And Engineering Of Luminophores For Aggregation Induced Electrogenerated Chemiluminescence, Jesy Alka Motchaalangaram

Dissertations

Most conventional luminophores produce intense emissions in solutions but suffer from weak emissions or quenching when aggregated in poor solvents due to intermolecular interactions, such as π-π stacking. This phenomenon is known as aggregation caused by quenching (ACQ), limits their applications in their solid state. In contrast, aggregation induced emission (AIE) is a phenomenon in which luminophores are weak- or non-emissive in solution but emit intensively in their aggregated or solid states. AIE has enabled significant advancements in various real-world applications and has inspired new areas of research. The combination of AIE with electrogenerated chemiluminescence (ECL) has resulted in a …

Development And Implementation Of Novel Mass Spectrometric Methods For Metabolism Studies In Drug Discoveries, Huifang Yao

Dissertations

The field of drug discovery has evolved significantly over the past few decades, with a growing emphasis on understanding the metabolic pathways and biotransformation processes that influence the pharmacokinetics and pharmacodynamics of drug candidates. Novel mass spectrometric methods have emerged as powerful tools in this domain, facilitating the comprehensive analysis of metabolic profiles and enabling the identification of metabolites with implications for safety, efficacy, and overall drug development. However, challenges remain in quantifying metabolic flux—an essential aspect of understanding drug action—particularly due to the limitations of traditional isotope kinetic assays, which often involve lengthy sample preparation and the use of …

Quinone-Mediated Extracellular Electron Transfer In Escherichia Coli During Glucose Oxidation Metabolism, Megan Danielle Whisonant

Theses and Dissertations

The growing global demand for energy, ongoing reliance on fossil fuels, and increasing water pollution from industrial and anthropogenic sources present significant environmental challenges. In response to these issues, renewable and sustainable energy sources offer substantial potential for reducing dependence on fossil fuels and ensuring access to clean water. Microbial electrochemical systems (MESs) have emerged as promising, eco-friendly solutions for energy-efficient wastewater treatment and bioremediation. A key challenge in MESs development is facilitating effective electron transfer between microorganisms and electrode surfaces. The first chapter of this thesis discusses the fundamentals of MES types, explains mechanisms of extracellular electron transfer, and …

Chemical And Physical Characterization Of Verbenaceae Essential Oils Using Modern Analytical Methods And Chemometrics, Aleksandra N. Hilliard

Master's Theses

Essential oils have been used for generations to treat various health issues, including mitigating insomnia, reducing stress, inflammation, and preserving foods, to mention a few. Essential oils have complex chemistry, which defines the essence of the host plant. Recently, increased commercial uses of essential oils have prompted attention at the governmental level to monitor the chemical, physical, or biological activity of essential oils. This study is an attempt to add new information for consumers to the understanding of the composition of essential oils.

Modern analytical techniques including FTIR-ATR, GC-MS, LC-MS-MS, multivariate analysis statistics, and physio-chemical techniques (electrochemistry, DPPH, TRC, and …

Novel, Ultra-Fast Electrochemical Sensors For The Enhanced Detection Of Neurotransmitters And Toxic Heavy Metals In Aqueous Solutions, Noel Manring

Theses and Dissertations

Neurodegenerative diseases (NDDs) are a growing global health concern, affecting millions of people worldwide. NDDs arise from the progressive loss of neuronal cell function, ultimately leading to cell death. Abnormal levels of neurotransmitters, the chemical messengers in the brain, have also been linked to NDDs. Despite various treatments and medications aimed at alleviating physical and mental symptoms, there is currently no cure or means to halt disease progression. While the exact pathogenesis of NDDs remain poorly understood, cognitive decline is largely attributed to brain volume reduction, particularly in the hippocampus. Clinical studies suggest that environmental factors, such as exposure to …

Electrochemistry At Work: Bouncing Batteries, Bryant Corbin, James Daniel, Jade Riddle

Fall Showcase for Research and Creative Inquiry

No abstract provided.

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 …

Development Of Novel Protein Digestion And Quantitation Methods For Mass Spectrometic Analysis, Yongling Ai

Dissertations

Proteins are the workhorses of biology, playing multifaceted roles in maintaining cellular function, signaling, and response to environmental cues. Understanding their abundance and dynamics is pivotal for unraveling the complexities of biological processes, which underpins the foundations of molecular and cellular biology. Accurate measurement of protein quantities provides insights into cellular homeostasis, facilitates the discovery of biomarkers, and sheds light on the molecular mechanisms of diseases, bridging the gap between the molecular intricacies of proteins and their functional consequences in health and disease. The evolution of protein quantitation methodologies, from classical colorimetric assays to sophisticated mass spectrometry-based approaches, has expanded …

The Room Temperature Electrolysis Of F-Elements In Aqueous And Ionic Liquid Media: Synthesis, Dissolution, And Reduction, Phillip George Hammer

UNLV Theses, Dissertations, Professional Papers, and Capstones

Procuring F-element metals is no simple task and often requires the use of caustic and hazardous materials at high temperatures. These materials are invaluable for a variety of scientific missions ranging from the elucidation of fundamental properties, as fast spectrum nuclear fuel forms, to pit production modernizing our nuclear stockpiles. Metallic actinide materials are essential to strategic and critical materials recovery, the nuclear energy sector, and weapons production. Room temperature electrolysis is envisioned as a process to recover laboratory scale (milligram to gram) quantities of actinide metals. This process closes the uranium chemical loop allowing the reclamation of materials for …

From Waste To Energy: The Electrochemical Reduction Of Co2 Using Recycled Nanostructured Catalysts, Ibrahim Badawy

Theses and Dissertations

The reduction of carbon dioxide (CO₂RR) using electrochemistry is a promising solution for the burgeoning global energy crisis. The overall vision of its implementation relies on renewable energy sources to power the reaction creating carbon neutral products and effectively closing the carbon cycle. Research in this field has come a long way since its inception in the mid-1900s. However, there remain significant hurdles and important considerations to overcome in order to reach full commercialization. Most electrocatalysts tested for CO₂RR have been designed solely for maximum performance while ignoring the environmental consequences if such a material were …

Dissolution And Electrochemical Recovery Of Uo2, Uo3, And U3o8 In Ionic Liquids, Katherine Iolani Thornock Luebke

UNLV Theses, Dissertations, Professional Papers, and Capstones

This research explores a novel method of increasing the solubility of uranium oxides and other actinide oxides in room temperature ionic liquids (IL) using direct dissolution. The goal is to further expand our knowledge of actinide dissolution and possible nuclear fuel cycle material applications using ionic liquids. The novelty of the methods is focused on the use of oxidizing gas generated using air passed through an ozone generator. While examples of dissolution exist in IL using acidic functionalized ionic liquids, the solubility of all possible oxide species was not demonstrated. Also, the addition of aqueous acid to IL containing actinide …

Development Of Novel Mass Spectrometric Methods For Reaction Screening, Oligosaccharide Detection, And Nitrosamine Quantitation, Qi Wang

Dissertations

Benefitting from its high detection sensitivity and specificity, mass spectrometry (MS) has become a powerful technique in academia and industry. The aim of this dissertation study is to develop new mass spectrometric methods for organic reaction screening, detection of oligosaccharide/glycan in complex matrices, and nitrosamine absolute quantitation.

First, an electrochemistry/mass spectrometry (EC/MS) platform is built to generate an N-cyclopropylaniline radical cation electrochemically and to monitor its reactivity toward alkenes, which leads to the discovery of a new redox neutral reaction of intermolecular [3 + 2] annulation of N-cyclopropylanilines and alkenes. Net redox neutral electrosynthesis is quite rare in synthetic organic …

Nitro-Aromatic Polymers For Conversion-Style Battery Cathodic Materials, Brady P. Samuelson

Honors Thesis

The development of organic electrode materials in rechargeable batteries has seen a resurgence in recent decades. This spike in interest is mostly due to the increased investments in renewable energy sources, grid-scale energy storage, and the rapid transition to electric vehicles. Current lithium battery cathode materials typically use some form of lithium metal oxide (specific capacity: 272 mAh g^-1 which has problems with limited capacity, thermal runaway, and an unreliable supply chain. Our research group’s solution involves investigating new lightweight, organic redox groups combined with a conductive polymer backbone to serve as a possible replacement for the cathode in …

Investigating Ionic Current Rectification As A Means Of Controllable Drug Delivery Using Silica Nanoparticles And Nano Porous Membranes, Katie L. Nolan

Honors College Theses

This project investigates a novel ionic current rectification (ICR) phenomenon created by the opening and closing of nanopores by charged silica nanoparticles (SNPs) under electrophoretic flow. This voltage-controlled opening and closing of the pores can be exploited to allow delivery of nicotine through the pores at programmable intervals. The ICR phenomenon was thoroughly investigated by varying pH, buffer concentration, SNP concentration, and applied voltage range. The mechanism was also verified by testing with a 2-, 3-, and 5-electrode system. Potential cake layer formation was demonstrated in a longer ICR test, and the implications of this on the drug delivery mechanism …

Electrochemistry Of Bubbles: Developing New Sensors, Promoting Gas Evolution Reactions, And Extraction Of Rare Earth Elements, Ruchiranga R. Ranaweera

Wayne State University Dissertations

This dissertation presents new analytical, electrocatalysis, and separation strategies that utilize bubble behaviors in different electrochemical systems. The first part of this dissertation focuses on the method development for PFAS preconcentration and detection. First, we present the bubble-nucleation-based electrochemical method for the selective and sensitive detection of surfactants. Our method utilizes the high surface activity of surfactant analytes to affect the electrochemical bubble nucleation and then transduces the change in nucleation condition to an electrochemical signal for determining the surfactant concentration. Using this method, we demonstrate the quantitation of perfluorinated surfactants in water, a group of emerging environmental contaminants, with …

Analysis Of Forensically Relevant Evidence Using Electrochemistry, Spectroscopy, And Mass Spectrometry Tools, Colby Edward Ott

Graduate Theses, Dissertations, and Problem Reports (ETD)

Forensic science relies on the use of multiple techniques in the assessment of evidence to increase the accuracy and reliability of the results. However, with the rapidly changing drug landscape due to the introduction of novel psychoactive substances, many traditional screening methods are no longer sensitive or selective enough for use. Additionally, many screening methods such as chemical color tests are prone to false positive and negative results and are subjective. Therefore, the goal of this dissertation was to develop a novel analytical scheme that can provide a more efficient, rapid, and sensitive method that will facilitate adoption in the …

Electrochemical And Mass Spectrometry Methods For Identification Of Gunshot Residues (Gsr) In Forensic Investigations, Kourtney A. Dalzell

Graduate Theses, Dissertations, and Problem Reports (ETD)

Gun violence continues to be one of most significant challenges straining the USA society causing thousands of human lives lost every year. In 2020 alone, firearm-related incidents including homicide, accidents, and suicides, reached a staggering number of over 43,000.^1,2 With the increase in these types of incidents, several service areas in crime laboratories are heavily impacted by the number of cases run on a yearly basis. These include firearm examinations, gunshot residue (GSR) analysis, bullet hole identification, and shooting distance determination, which are crucial to support a criminal investigation and, overall, the justice system in our country. These areas …

Electrochemical Oxidation Of Individual Silver Nanoparticles: Exploring The Effect Of Particle Shape, Capping Ligand, Electrolyte, And Potential On The Signal, Jazlynn Sikes

Graduate Theses and Dissertations

Nanomaterials have revolutionized science and technology. Their unique properties can be exploited, and nanoparticles are being used as catalysts, antimicrobials, drug delivery vehicles, sensors, and more. However, the fundamental properties of nanomaterials and their interactions with their surrounding environments are still poorly understood. In this work, a single-particle approach was used to observe the effects of capping ligand, surrounding solution, and particle shape on the oxidative process to gain deeper understanding of silver nanoparticle properties. When allowed the opportunity, the particles will adsorb to the electrode surface then oxidize in rapid succession upon electrode activation, regardless of capping ligand as …

Novel Applications Of Mass Spectrometry For Quantitation And Reaction Mechanism Elucidation, Pengyi Zhao

Dissertations

Mass spectrometry (MS) has been growing as one of the most widely used tools in the field of analytical chemistry. Various applications have been developed to harness the high sensitivity and specificity of mass spectrometric analysis. In this dissertation, two major challenges are addressed. By developing mass spectrometric-based methods, absolute quantitation of proteins/peptides have been achieved. Elucidation of various reaction mechanisms are also enabled. These are the focuses of this dissertation.

In Chapters 2 to 4, a novel quantitation method is developed, titled as coulometric mass spectrometry (CMS). The strength of this method is that no reference standard or isotope-labeled …

Electrostatic Denaturation Of Dna-Cisplatin Adducts, Eddie Madrigal

Master's Theses

In this thesis, electrochemical approaches are used to determine the properties of deoxyribonucleic acid (DNA) by electrostatic denaturation. The electrochemical routine involves an application of a destabilization potential, an equilibration potential, and a square wave voltammogram (SWV) to monitor the extent of melting. Our method uses a monolayer consisting of thiol modified DNA and mercaptohexanol on a gold electrode. These electrodes are then incubated in a complementary sequence tagged with methylene blue. By using our electrostatic denaturation technique, different parameters are explored, such as surface densities, surface coverages, and ionic strengths. As proof of concept, these techniques were applied toward …

Electrochemical Reduction Of Carbon Dioxide And Carbon Monoxide For The Production Of Green Fuels And Chemicals., Jacob M. Strain

Electronic Theses and Dissertations

It has become apparent that closing the carbon cycle on this planet in order to mitigate disastrous consequences of runaway global warming has become one of the most pressing issues of our civilization. One of the ways we need to accomplish this goal is by finding news methods to generate fuels that will be carbon neutral. Renewable fuels and green chemicals will be a major component of closing the carbon cycle and restoring our planet’s ecosystem into a sense of balance. A method that can help achieve this goal is the reduction of CO₂. If CO₂ can …

Investigation Of Underpotential Deposition Of Copper At Heated Gold Loop Screen-Printed Electrodes In A Variety Of Water Samples, Eun-Ju Lee

Legacy Theses & Dissertations (2009 - 2024)

To study the underpotential deposition (UPD) of copper, three different types of water samples (TraceSelect® Ultra-pure water, Indian pond water at University at Albany and tap water) are used at a heated gold loop screen-printed electrode (GLE), which is a new type of heated working electrode for voltammetry measurements that is able to directly detect the copper content in the water samples. The anodic stripping analysis of copper is performed with these gold loop electrodes at room temperature of 25 °C and electrode temperature of 80 °C at two different deposition potentials, -0.20 V and +0.10 V. Furthermore, the concentration …

Structural Annotation Of Electro- And Photochemically Generated Transformation Products Of Moxidectin Using High-Resolution Mass Spectrometry, Lisa Kotthoff, Sarah-Louise O'Callaghan, Jan Lisec, Tanja Schwerdtle, Matthias Koch

Articles

Moxidectin (MOX) is a widely used anthelmintic drug for the treatment of internal and external parasites in food-producing and companion animals. Transformation products (TPs) of MOX, formed through metabolic degradation or acid hydrolysis, may pose a potential environmental risk, but only few were identified so far. In this study, we therefore systematically characterized electro- and photochemically generated MOX TPs using high-resolution mass spectrometry (HRMS). Oxidative electrochemical (EC) TPs were generated in an electrochemical reactor and photochemical (PC) TPs by irradiation with UV-C light. Subsequent HRMS measurements were performed to identify accurate masses and deduce occurring modification reactions of derived TPs …

An Electrochemical Instrument For The Analysis Of Heavy Metals In Water Via Anodic Stripping Coulometry For Applications In Remote Sensing., Kelsey Lynn Kaht

Electronic Theses and Dissertations

From the high levels of arsenic in groundwater in Bangladesh to the lead contamination of drinking water in Flint, Michigan, there are incidents across the globe that highlight the need for a reliable instrument capable of monitoring heavy metals remotely and continuously in a variety of geographical locations. Typical instrumentation for water analysis, such as ICP and AAS, must be housed in a central lab and relies on an operator traveling to the collection site, obtaining a sample, and transporting it back to the lab. This analysis provides a snapshot of the water quality that is limited to the specific …

Modification And Optimization Of Conducting Polymer-Modified, Redox-Magnetohydrodynamics (R-Mhd) Pumping For Enhanced And Sustained Microfluidics Applications, Md Foysal Zahid Khan

Graduate Theses and Dissertations

In this work, a novel microfluidic pumping approach, redox-magnetohydrodynamics (R-MHD) has improved by materials and device optimization to use in lab-on-a-chip applications. In R-MHD, magnetic flux (B) and ionic current density (j) interacts to generate body force (FB) in between active electrodes, according to the equation FB = j×B. This unique fluid pumping approach is scalable, tunable, generates flat flow profile, and does not require any channels or valves. Pumping performance, such as speed scales with the ionic current density (j) and duration depends on the total charge (Q). The ionic current density (j) results from the conversion of electronic …

Recent Advances In Nanofluidic Electrochemistry For Biochemical Analysis, Zhong-Qiu Li, Zeng-Qiang Wu, Xing-Hua Xia

Journal of Electrochemistry

Nanofluidics, as a young research field, has been receiving more and more attentions. It has been successfully applied in various fields including nanoscale separation, biochemical sensing and energy conversion. The development of nanofluidics is closely related to electrochemistry that can provide a driving force for the study of the material transport characteristics in nanopores/nanochannels. On the other hand, nanopores/nanochannels can creat a microenvironment for study of spatially nanoconfined electrochemistry. The combination of nanofluidics and electrochemistry has given rise to many new theories and technologies for single molecule/particle analysis and nanofluid manipulation. Herein, we provide a review of the recent progresses …

A Low Noise Temperature Control System For Nanopore-Based Single Molecule Analysis, Cheng-Yu Yang, Zhen Gu, Zheng-Li Hu, Yi-Lun Ying, Yi-Tao Long

Journal of Electrochemistry

Nanopore employs a single bio-molecule interface, which is a highly sensitive single-molecule detection technology for measuring single biomolecules such as DNA, RNA, protein, and peptide. The interaction between single molecule and nanopore is thermodynamically controlled. Therefore, it is urgent to precisely control the temperature of the nanopore system without introduction of any noise. In this paper, we have developed a low-noise temperature control system for single-molecule detection of nanopores to achieve precise regulation at the ambient temperature during measurements. The system utilizes the thermoelectric effect of the semiconductor refrigerating chip to heat or cool the detection chamber, while adopts electromagnetically …