Physical Sciences and Mathematics Commons^™

Optimization Of Electrode Configurations For Calibration-Free, Remote Sensing Of Heavy Metals In Water Using Double-Potenital Step Anodic Coulometry, Jessica Bone

Online Theses and Dissertations

Many areas around the world are known and predicted to suffer from arsenic-contaminated drinking water resulting in elevated medical issues. Current arsenic detection techniques require that a sample be taken at the site, carried to the lab, and then tested by a skilled technician, which is not practical for remote, hard to reach places. In collaboration with researchers at the University of Louisville and the University of Kentucky, we are designing an electrochemical cell for a calibration-free detection technique that can be performed remotely, eliminating the need for on-site technicians, and helping to prevent chronic arsenic poisoning. A validated and …

Decoding The Flavor Of Kentucky's Native Pawpaw Fruit, Mackenzie Leanne Roark

Online Theses and Dissertations

The objective of this research was to decode the flavor of Asimina triloba, or the pawpaw fruit, to identify and quantitate the aroma-active compounds that are present. Gas chromatography – olfactometry (GC-O) was applied on capillary GC columns with various means of extraction. The volatile compounds present were extracted using both headspace solid phase micro-extraction (HS-SPME) for 30 minutes at 23°C and 50°C, and solvent extraction using methylene chloride. The sample extracts were analyzed with both gas chromatography – mass spectrometry (GC-MS) and gas chromatography – olfactometry (GC-O). To eliminate potential artifacts that were observed when using HS-SPME at 50°C, …

Neutral And Charged Bis(Triarylamines) For Use In Grid Scale Battery Technologies, Taylor Matthews

Online Theses and Dissertations

Energy storage systems allow flexibility in control and maintenance of the electric grid while integrating renewable energy resources to mitigate carbon emissions. Redox flow batteries (RFBs) are stationary energy storage systems that convert chemical energy to electrical energy by charge-transfer reactions. Designing molecules that are capable of stable multi-electron redox reactions per active-species molecule can increase the efficiency of future systems. Spectroelectrochemistry, the combination of spectroscopy and electrochemistry, allows for quantitative and qualitative analyses of electron-transfer processes. The focus of this research is to use optical and electrochemical properties obtained from spectroelectrochemistry to determine the stability of neutral and charge …

Chromatographic Studies Of Some Hormone And Metabolic Modulators Used For Doping In Sports, Ruth Marie Speidel

Online Theses and Dissertations

The World Anti-Doping Agency (WADA) is an international agency that monitors the use of Performance Enhancing Drugs (PEDs) in sports; their mission is “to lead a collaborative worldwide movement for doping-free sport” (Who We Are, 2022). For this mission, the WADA needs quick, sensitive, reproducible, and accurate methods for analyzing athletes’ biological fluids for possible PEDs. This research focuses on developing and validating simple, sensitive, rapid, and reliable gas chromatography- mass spectrometry (GC-MS) methods for the analysis of two hormone and metabolic modulators, toremifene and trimetazidine. Previously, there has been limited GC-MS methods used to analyze toremifene and trimetazidine. Quantification …

Absorbent Household Materials For The Collection Of Ignitable Liquid Residues From Surfaces Of Varying Porosity, Jessica Carlotti

Online Theses and Dissertations

Ignitable liquids (ILs) are used as accelerants to burn items at a faster rate and the presence of an IL indicates that arson has occurred. Upon arrival to an arson scene, fire investigators access the scene and collect substrates containing ILs. The substrates, such as concrete and wood, are removed from the scene by methods that are time consuming, and require heavy machinery and tools. The evidence is transported in air-tight containers to the laboratory where analysts identify the chemical classification of the IL using gas chromatography mass spectrometry (GC-MS). In this work, readily available absorbent household materials such as …

Structural Investigation On The Thermal Degradation Of Aqueous Amines In Post-Combustion Co2 Capture, Jeffrey Alexander Laub

Online Theses and Dissertations

One of the major issues concerning the increase in global temperature is with the elevating levels of CO2 in the atmosphere. Combustion of fossil fuels in power plants is a leading contributor to the elevated anthropogenic CO2 concentration. To help alleviate this issue, the investigation of aqueous amines being implemented for the capture of CO2 in the post-combustion carbon capture (PCCC) in power plants has been a growing interest to chemists. One of the concerns with aqueous amines, is their ability to thermally degrade. Thermal degradation is a prominent aspect for the loss of aqueous amines during the stripper process …

Effects Of Nutrient Overload And Environmental Conditions On Algal Bloom Formation: A Case Study Of Water Sources In Eastern Kentucky, Lauren Sutton

Online Theses and Dissertations

Eastern Kentucky is home to many private ponds used for agricultural and recreational purposes. Each year, the owners of these ponds observe harmful algal blooms (HABs) that release toxins into the water, potentially limiting the use of these ponds. A pilot study in summer 2018 observed a harmful algal bloom (HAB) occurring in one pond in Madison Country that roughly correlated with a rise in water sulfate levels with no detectable levels of nitrate or phosphate present. A follow-up study of this pond and others in the area was conducted during Summer 2019. The purpose of this project was three-fold: …

Development Of Novel Analytical Methods For Detection And Determination Of Tamoxifen In Oral Fluid And Discrimination Between Regioisomeric Aromatase Inhibitors For Doping Control Purposes, Brooke A. Sutton

Online Theses and Dissertations

The use of SERMs (Selective Estrogen Receptor Modulators) – most notably the drug Tamoxifen – has significantly increased among athletes over the past decade to enhance athletic performance and/or negate certain side effects of using anabolic steroids. This “doping” is always banned by WADA (World Anti-Doping Agency) for all athletes, but SERMs can naturally increase testosterone production so they are a tempting alternative to using steroids or androgenic supplements that can cause significant health problems (e.g. acne, breast development, frequent urge to urinate, low libido, etc.). Similarly, the use of AIs (Aromatase Inhibitors) has also increased among athletes for identical …

Influence Of Applied Potential And Metal Ion Concentraion On Metal Electrodeposition At Micron Gap Gold Electrodes, Krista Michel Riggins

Online Theses and Dissertations

Zamborini and Coworkers developed, a simple, low cost, and highly parallel electrochemical approach for fabricating nano-scale (metal/metal) or molecular (metal/polymer or self-assembled monolayer (SAM)/metal) junctions that should be useful in preparing working sensors and molecular electronic devices. The fabrication of metal/metal junctions involves metal deposition on one set of electrodes (E1), where the metal grows and becomes connected to a second set of electrodes (E2) of an Au interdigitated array of electrodes with a 5 µm separation. However, when different metals were deposited, they deposited in different fashions. Ag grew in the form of wires and Palladium deposited in the …

Determination Of Atrazine Concentration In Freshwaters Using Fluorescence Spectroscopy, Boniface Osei Amankona

Online Theses and Dissertations

Atrazine is the most widely used herbicides in USA, but its negative impact on aquatic ecosystem cannot be over-looked. Atrazine was traditionally determined through liquid/gas chromatography or IR spectroscopy. However, these methods are either time-consuming or costly, so fluorescence spectroscopy is investigated as a more cost and time efficient alternative. Literature value of the optimal wavelength of atrazine was found to be 350 nm emission. Experimental value for emission scanned of atrazine resulted in an optimal wavelength of 363 nm. Known and unknown concentrations of atrazine will be analyzed using fluorescence spectrophotometer to develop a calibration curve.

The calibration concentration …

Oil Dries: A New Absorbent Material For Collection Of Ignitable Liquids From Semi-Porous Material, Jessica Sosa

Online Theses and Dissertations

Extraction of an ignitable liquid sample from a semi-porous surface such as concrete is especially difficult. For this purpose, two different solid oil dry absorbent materials, Instazorb and MAXXAbsorb, were researched for use of collection of ignitable liquid samples at a fire scene. These oil dries were spiked with different ignitable liquids (Coleman fuel, gasoline, kerosene, and diesel). Isolation of the ignitable liquid from the oil dry absorbent was accomplished by passive headspace isolation. Data was obtained by gas chromatography coupled with flame ionization detection (GC-FID) and gas chromatography coupled with mass spectrometry (GC-MS). Chromatograms obtained from both oil dries …

Latent Fingerprint Enhancement On A Brass Metal Surface Using Paint Electrodeposition, Reika D. Haskell

Online Theses and Dissertations

Fingerprint evidence recovered at a crime scene plays a key role in apprehending a suspect. Cyanoacrylate fuming is one the most successful methods of enhancing fingerprints from metallic surfaces. Despite the success of cyanoacrylate fuming, fingerprint recovery on fired cartridge casings is rarely successful. Therefore, a new fingerprint development method is needed to enhance fingerprint evidence that may still be present on fired cartridge casings. The aim of this research project is to study the use of metal and paint electrodeposition to enhance fingerprints on a brass metal surface.

High throw power paint was used in the initial study; high …

Methods Of Analysis For Fermentation Science Products Using Various Analytical Techniques, Casey Jay Howdieshell

Online Theses and Dissertations

Fermentation science, the study of microorganisms as they digest food sources to produce usable products for consumption, has been around since the dawn of modern civilization. Historically, the fermentation process has been utilized for the production of alcoholic beverages. More recently, however, the production of bioethanol and biodiesel as a fuel source alternative to classical fossil fuels has gained increased popularity. As with any synthetic process, derivations and optimizations for ideal production are needed. As such, analytical techniques must be implemented to ensure quality control and pinnacle efficiency. This body of work describes analytical techniques providing key qualitative and quantitative …

Preparation And Characterization Of Self-Assembled Monolayers And Mesoscale Protein Patterning, Panae Noomuna

Online Theses and Dissertations

Bottom-up approach was used to develop self-assembled monolayers of octadecyltrichlorosilane (OTS) and undecenyltrichlorosilane(UTS) on Si(100) wafer. Undecenyltrichlorosilane monolayer was oxidized at the vinyl terminal to generate a carboxylic acid group. Lysozyme protein was immobilized on the polar carboxylic acid group. The developed protein patterns were investigated using fluorescence microscopy. Lysozyme has an isoelectronic point of 11.35. At a pH below this value the protein is positively charged making it a good candidate for electrostatic adsorption on the negatively charge -COO- group. Fluorescence images confirm formation of lysozyme across the silicon wafer. The patterned Si(100) wafer can be used as a …

Deuterium Tracer Study Of The Mechanism Of Iron Catalyzed Fischer-Tropsch Synthesis, Yunxin Liao

Online Theses and Dissertations

The Fischer-Tropsch Synthesis (FTS) was invented in 1920s, shortly after its invention, it became an important way to produce synthetic fuels. The FTS is also an important way to understand the origin of life. Even though the FTS has been used to produce liquid fuels commercially for a relatively long time, the mechanism of FTS is still unclear, a mechanism can explain all the experimental observations has not been discovered yet.

By conducting H2/D2 switching experiments we found that there was an inverse isotope effect in the Fe catalyzed FTS. The rate of hydrocarbon production was increased when syngas H2/CO …

Synthesis Of Novel Ionic Liquid Tagged Porphryin Media Designed For The Oxidation Of Lignin, Joseph Hugh Franklin Baker

Online Theses and Dissertations

The ever growing need for a viable renewable fuel source has led to this thesis project; the biomimetic lignin degradation by means of a homogeneous oxidative catalyst in corresponding ionic liquids. Lignin comprises nearly a third of lignocellulosic biomass and is cross-linked to both cellulose and hemicellulose. Current utilization methods of lignin do not generate the full value of the polymer, because they do not yield many of the valuable feed stock chemicals it is comprised of. To improve the value of the biomass as a whole and create a viable economy for the US's transition to biofuels, better utilization …

Ambient Ionization Mass Spectrometry Analysis Pertaining To Biofuel Process Development, Sushma Dendukuri

Online Theses and Dissertations

Mass spectrometry (MS) has undergone a revolution with the introduction of a new group of desorption/ionization (DI) techniques known collectively as Ambient Ionization mass spectrometry. Ambient ionization mass spectrometry allows for direct analysis of analytes and typically requires little or no sample preparation. Specifically, Direct Analysis in Real Time (DART) has developed rapidly and allowed investigations to occur with the analysis of biomass after various pretreatments to determine the pretreatment biomass degradation efficiency. The degradation of the initial biomass structure is a very important step before other chemical treatments can occur to generate needed sugars. Since generated sugars aid in …

Deuterium Tracer Studies Of The Mechanism Of Cobalt Catalyzed Fischer-Tropsch Synthesis, Chunfen Jin

Online Theses and Dissertations

Since the Fischer-Tropsch (FT) catalytic polymerization reaction has been discovered in 1920s, many kinds of possible mechanisms have been reported. However, there is still debate because there is a lacking of experimental evidence to discriminate the validity of each mechanism. To define the mechanism of Fischer-Tropsch-Synthesis (FTS), we must define the C-C formation pathways as well as the structure of initiator species in the process, and finally provide an explanation in mechanistic detail as to how branched hydrocarbon compounds are formed in the reaction sequence.

In order to understand the cobalt catalyzed mechanism of FTS, we conducted H2/D2 switching and …

Optimization And Validation Of Direct Analysis In Real Time Mass Spectrometry (Dart-Ms) For Quantitation Of Sugars To Advance Biofuel Production, Daudi Sayialel Saang'onyo

Online Theses and Dissertations

A direct analysis in real time mass spectrometry method was developed and validated for the analysis and quantitation of sugars that would be generated from pretreated and hydrolyzed switchgrass. This research aspect can be divided into two sections:

i) Literature Review: A review is presented on the status of energy security and how biomass and biofuels can be utilized as a source of transportation fuel. To this end, biomass (specifically switchgrass) can be broken down by pretreatment methods and then enzymatically hydrolyzed to simple sugars. These sugars can assist with algae growth that can eventually be converted into biofuels. …