Analytical Chemistry Commons^™

Dataset For Characterization Of ‘Cool’ And ‘Warm’ White Leds, Edward Navarre

SIUE Faculty Research, Scholarship, and Creative Activity

The emission properties of “cool” and “warm” white LEDs were studied. The suitability of pulse-width modulation as a method to control LED brightness was examined. Both types of LED demonstrated emission standard deviation minima at a PWM frequency greater than 2000 Hz. The functional wavelength ranges of the LEDs were approximated using the linearity of brightness as a function of pulse-width modulation duty-cycle and the root mean squared deviation from mean for absorbance measurements. Both LED types demonstrated good stability in absorbance measurements over long operation times. The “warm” LED demonstrated a broader range of wavelengths useful for spectrophotometry. This …

Assessing Competitive Reaction Rates In The Nitration Of 2-Methylbiphenyl, Biphenyl, And Toluene To Determine Steric Restriction In Resonance-Stabilized Planarization Of The Carbocation Intermediates, Victor A. Hanson, Tristan Wine, Kevin Bartlett, Joshua Padilla, Alessandro Rizzi

Honors Projects

Electrophilic aromatic substitution (EAS) reactions have long been a fundamental addition to sophomore-level organic chemistry classes, allowing students the opportunity to explore the electron donating and withdrawing effects of electrons contained in the substituents of the aromatic reactant. In this paper we present preliminary findings on the nitration of methylated biphenyls using kinetic and regioselective assessments to analyze steric influences on the planarization of 2-methylbiphenyl after EAS nitration. Our preliminary findings show that nitration favors the methylated phenyl ring of 2-methylbiphenyl, indicating that the steric influence of the methyl group restricts planarization of the carbocation intermediate. Furthermore, a competition nitration …

Photosensitization And Analytical Study On Reactive Oxygen Intermediates: Self-Sorting Surface Radicals And “On-Off” Sensitizer Function Mechanisms, Sarah J. Belh

Dissertations, Theses, and Capstone Projects

This thesis consists of four chapters which are detailed below. Chapter 1 is an introductory chapter, which lays out the background and purpose of the research.

Chapter 2 describes a study of the mobility of alkoxy radicals on a surface by detection of their recombination product. A novel method called symmetrical product recombination (SRP) utilizes an unsymmetrical peroxide that upon sensitized homolysis recombines to a symmetrical product [R'OOR → R'O•↑ + •OR → ROOR]. This allows for self-sorting of the radical to enhance the recombination path to a symmetrical product, which has been used to deduce surface migratory aptitude. SPR …

Isolation And Determination Of The Composition And Structural Components That Comprise Dissolved Organic Matter Using Normal Phase Liquid Chromatography, Jonathan A. Long Jr

LSU New Orleans Theses and Dissertations

A comprehensive understanding of the reactivity associated with organic carbon is critical for recognizing the behavior of newly formed compounds in aquatic environments. In an effort to study the reactivity of complex mixtures, understanding the different processes affiliated with them are key. Understanding the reactivity associated with organic carbon can help to improve chromatographic separation. Using a combination of light and heavy crude oil, a separation procedure was developed to obtain a complete representation of the aromatic subfraction of the crude oil sample. The crude oils were separated into four distinct fractions based on the number of condensed aromatic rings …

Modeling Biliary Polycyclic Aromatic Hydrocarbon Metabolites In Fish Using High Performance Liquid Chromatography With Fluorescence Detection, Principal Component Analysis, And Partial Least-Squares Analysis, Joshua C. Padilla

Honors Projects

Polycyclic aromatic hydrocarbons (PAHs) constitute a diverse class of highly toxic, ubiquitous environmental pollutants, and are thus of high interest in environmental monitoring and regulation. In this study, biliary samples of English soles Parophrys vetulus and smallmouth bass Micropterus dolomieu from Seattle waterways, and chum salmon Onchorynchus keta from the north Pacific Ocean were analyzed by high performance liquid chromatography with fluorescence detection (HPLC-FLD) to gauge PAH exposure. Samples were profiled in three broad molecular weight categories, to capture naphthalene-like (NAPH), phenanthrene-like (PHEN), and benzo[a]pyrene-like (BAP) metabolites. While quantification was not achieved for the chum salmon, the semi-quantitative measurements of …

The Reactivity Of Metal Phosphites: Oxidative Rate Analysis, Jamie Kitchens

Symposium of Student Scholars

Phosphorous compounds are involved in many of the biomolecular processes deemed fundamental for life. DNA, ATP, and phospholipids are a few of the molecules where phosphates can be found in the body. Phosphates are geochemically characterized by their low solubility and poor reactivity. This has led to the investigation of reaction mechanisms that could lead to the formation of the phosphorous compounds found in organisms. The oxidation of phosphite into phosphate could be how phosphates were introduced to life, due to phosphites being more soluble and more reactive than phosphates. We will present the synthesis and oxidation reactivity of four …

Electrochemical And Spectroscopic Characterization Of Cerium Salts And Nanoceria Material, Emily Velarde, Wei Zhou

Symposium of Student Scholars

The nanoscale form of cerium oxide, nanoceria (nano-CeO_x), has drawn great attention in recent years in electrochemical, nanomaterial research and medicinal studies due to its antibacterial properties, UV absorption, and its biochemical function as possible radical scavenger. Many new synthesis methods have achieved uniform and biocompatible nanoceria particles, and our lab has created cerium oxide particles that shows UV/Vis. absorption and X-ray patterns similar to the commercial nanoceria and nanoceria made in other research laboratories with novel synthetic methods.

This study focuses on charactering and comparing electrochemical properties of cerium inorganic salts and synthesized nanoceria. Preliminary results …

Bioanalytical Determination Of Glucose Concentration In Sports Drinks Using Uv/Vis Spectroscopy, Laney Hedgeman, Brianna Bond

Symposium of Student Scholars

Abstract

The purpose of our project is to indirectly monitor the enzymatic activity of glucose oxidase as it reacts with the glucose present in sports drinks through the quantitative analysis of the generated ferricyanide. As glucose oxidase catalyzes the oxidation of beta-D-glucose in the presence of oxygen, D-glucono-1,5-lactone is produced along with hydrogen peroxide. The hydrogen peroxide is used in a subsequent reaction with ferrocyanide catalyzed by horse radish peroxidase to produce water and the chromophore ferricyanide. This compound absorbs in the ultraviolet/visible spectrum at 420 nm, which can be quickly measured using Ultraviolet/Visible Spectroscopy. Since the molar ratio of …

Advancing The Preclinical Development Of Secondary Metabolites From Cacospongia Mycofijiensis For The Treatment Of Cancer, Joseph Morris

Natural Sciences and Mathematics | Biological Sciences Master's Theses

The marine sponge Cacospongia mycofijiensis from the Indo-Pacific has proven to be a source of structurally diverse secondary metabolites that are biologically active against a variety of distinct targets. Current interest in the secondary metabolites of C. mycofijiensis largely stems from a) their potent and preferential cytotoxicity for cancer cell lines versus normal cells, making many of them promising leads as cancer therapeutics and b) the novel mechanisms of action responsible for their impressive cytotoxicity. However, limited compound availability has resulted in a paucity of studies aimed at advancing the preclinical development of these secondary metabolites from C. mycofijiensis for …

Cu-Promoted C-H Bond Hydroxylation Inspired By Cu-Dependent Metalloenzymes, Rachel Trammell

Chemistry Theses and Dissertations

From 2003 to 2015, Schӧnecker and Baran proposed a dinuclear Cu/O₂ species in their mechanistic proposal for the hydroxylation of sp³ C-H bonds within their systems (proposed based on yields). Inspired from the site selectivity of this methodology and poor analysis of the mechanism, the first project was inspired to re-examine the sp³ C-H bond hydroxylation by Schrӧnecker and Baran and perform an intensive investigation into understanding how Cu/O₂ interact which led us to propose a new mechanism based on the evidence collected (i.e., LCu^II-hydroperoxide species that undergoes homolytic O-O bond cleavage). From there …

Initial Investigation Of Wildflower Honey Using Headspace Solid-Phase Microextraction Coupled With Gas Chromatography-Mass Spectrometry For Geographical Information, Tyra Countiss

Honors Theses

Honey has been used as a food, sugar substitute, and flavor enhancer forever. The uses for honey are extremely varied from food to medicine. It is widely touted that you can address seasonal allergies, especially those following a move, by eating local honey. For this to be true the composition of the local honey, including trapped pollen, would allow allergy symptoms to be eliminated. In this project, the volatile and semi-volatile aroma compounds in wild flower honey from several different locations were analyzed. Headspace solid phase microextraction (HS-SPME) coupled with gas chromatography-mass spectrometry (GC-MS) was used to help develop the …

Determination Of Metals And Microplastics In Sediment From Oyster Reefs In The Mississippi Sound, Shelby Goza

Honors Theses

This research centers on the determination of metals (Cd, Pb, V, Cr, Mn, Fe, Co, Ni, Cu) and microplastics (MPs) in marine sediment from oyster reefs in the Mississippi Sound Estuary. Oysters (Crassostrea virginica) are a vital part of the Gulf Coast economy, but their population has dramatically declined in recent years due to multiple stressors, including oil spills and fluctuations in salinity from flooding. Increasingly frequent flooding events also introduce high loads of MPs and sediments containing heavy metals from the Mississippi River. These pollutants can have deleterious effects on oyster biology; however, they have not been adequately …

Effects Of Halogen Bonding On 13c Nmr Shifts Of Various Tolan Species, Anthony Lybrand

Honors Theses

Halogen bonding is slowly becoming a more and more useful part of the world of chemistry and is beginning to be incorporated into various aspects of the chemical industry. This study’s purpose is to determine whether or not halogen bonding can cause any effect in the 13C NMR shifts. The specific purpose of this study is to determine whether these chemical shifts change when a Lewis Base is added to the dissolved sample. In order to do this, the tolan species (4-iodotolan and 4-chlorotolan) had to be synthesized. Once synthesized, the tolan species were analyzed via NMR. NMR data indicated …

The Power Of Sulfur: A Study Of An Isothiocyanate Chiral Derivatizing Agent, Thioamide Based Chiral Solvating Agents, And The Geometry Of Sulfonamides, Emily B. Crull

Dissertations

This three-part dissertation is connected by the thread of utilizing sulfur-based functional groups, hence the power of sulfur. The first project was the development of a pentafluorobenzene based isothiocyanate chiral derivatizing agent (CDA), a class of compounds that differentiate enantiomers through covalent bond formation. This project, which was addressed using a combination of synthetic and computational methods and NMR analysis, gave rise to an CDA that was highly selective for amines and computationally predictable. Branching off of that, the second project demonstrated the use of two thioamide chiral solvating agents (CSAs), which had never been reported as a core functional …

Kinetics For Enzymatic Conversion Of Biomass To Glucose, Jordan Broadwater

Undergraduate Honors Theses

Biofuels are a sought-after alternative for fossil fuels in today’s society. More specifically, cellulose-based biofuel is an avenue of research intending to limit waste and provide new renewable energy. Cellulose is a rigid polymer of glucose monomers that is found abundantly across different agriculture crops. However, its stability is a barrier to energy production from this source. Pretreatment followed by hydrolysis of cellulosic materials serves a potential to produce glucose to be used in biofuels in larger quantities compared to other methods. This project studied the effect microwave pretreatment and oxygenation have on hydrolysis of cellulose in Arundo Donax. Arundo …

A Project To Dye For : Differentiation Of Dyed And Non-Dyed Human Hairs Using Atr Ft-Ir Spectroscopy, Joseph John Greco

Legacy Theses & Dissertations (2009 - 2024)

IR spectroscopy is widely utilized for forensic purposes due to the chemical fingerprint the method provides. ATR FT-IR spectroscopy is particularly advantageous because it allows for spectra to be collected quickly, accurately, and perhaps most importantly for forensics, non-destructively. Human hair is commonly collected at a crime scene, and further analyzed using DNA analysis and microscopy. However, these techniques have limitations. In the past ATR FT-IR spectroscopy has shown promise in the analysis of human hair for forensic purposes. In this study, the differentiation of undyed hair versus dyed hair classes of varying colors based on their IR spectra were …

Developing A Microdialysis Sampling-Based Biofilm/Macrophage Co-Culture Model, Alda Diaz Perez

Graduate Theses and Dissertations

The host immune system and bacterial cells are known to interact during the human lifetime. Bacteria secrete a wide variety of signaling molecules, known as quorum sensing (QSC) molecules, that modulate the host immune system. While immune-biofilm interactions involve this chemical signaling network, the mechanisms through which this occurs are not well understood. This work aimed to develop a new method that can be used not only in vitro settings but also in vivo. The microdialysis sampling technique has widely been used in in vitro and in vivo settings in humans, mice, and rats for the collection of neuropeptides, cytokines, …

Heavy Metals In Ends Liquids: A Comparative Analysis Of Products From The United States, England, Canada, And Australia, Ashleigh Coggins-Block

Forensic Science Theses

The International Tobacco Control (ITC) Policy Evaluation Project 4-Country Survey, which this thesis is a part of, aims to compare policies and electronic nicotine delivery system (ENDS) products between the United States, England, Canada, and Australia. Since they can pose many serious health risks, this thesis investigated the presence of and source of heavy metals, including lead, nickel, chromium, and cadmium, in ENDS e-liquids. The source of these metals in ENDS e-liquids has been disputed between cultivated tobacco used to derive nicotine and the metal parts of ENDS devices. ENDS purchased in 2017 from each of the four countries of …

Electrodeposition Of Hydrogen Molybdenum Tungsten Bronze Films And Electrochemical Reduction Of Carbon Dioxide., Mohammad Bajunaid

Electronic Theses and Dissertations

The foremost aim for performing this study was to focus on the electrodeposition of mixed hydrogen molybdenum tungsten bronze films, which have the potential for e^– transfer interactions carrying out the reduction of carbon dioxide. A yellow peroxymolybdic tungstate solution was prepared and used for the electrodeposition of hydrogen molybdenum tungsten bronze films on conductive carbon paper. Electrodeposition was carried out at -2.0 V from 20 - 120 minutes to determine the effect of deposition time on film thickness and CO₂ reduction. These films were characterized by X-ray photoelectron spectroscopy. The deposited films served as a working electrode …

Theranostic Nanoparticles Folic Acid-Carbon Dots-Drug(S) For Cancer, Godwin Kweku Babanyinah

Electronic Theses and Dissertations

This study aims to prepare theranostic nanoparticles (NPs) that are expected to increase cancer diagnostics and therapeutic efficacy. We prepared the NPs constituting carbon dots (CDs) as an imaging agent, folic acid as a targeting agent, doxorubicin (DOX), or gemcitabine (GEM) as chemotherapy agents. The NPs include noncovalent FA-CDs-DOX, covalent CDs-FA-DOX, and covalent FA-CDs-GEM. Through ultraviolet-visible spectroscopy, fluorescence spectroscopy, and Fourier transform-infrared spectroscopy, the fabrication of these NPs was confirmed. It was discovered that the high drug loading efficiency is the noncovalent series while the high drug loading capacity is the covalent series The in-vitro pH-dependent drug release data indicate …