Analytical Chemistry Commons^™

Adsorption Of Antibiotics In Wastewater By Stevia Rebaudiana Zinc Oxide Nanoparticles, Hania Guirguis

Theses and Dissertations

Green zinc oxide nanoparticles (ZnO NPs), synthesized using Stevia rebaudiana extract, are investigated as novel adsorbents for the removal of the antibiotics ciprofloxacin (CIP) and tetracycline (TET) from water. The green ZnO NPs were synthesized using a novel, rapid and ecofriendly technique that utilized a natural source with high sugar content as a reducing agent and a less energy intensive approach that did not require annealing or calcination at high temperatures. The particles are mesoporous, with a hexagonal wurtzite structure, a BET surface area of 15.28 m2/g and a size range of 37.36-71.33 nm. At pH 5, the green ZnO …

In-Vial Detection Of Protein Denaturation Using Intrinsic Fluorescence Anisotropy, Krishnakumar Chullipalliyalil, Khaled Elkassas, Michael Mcauliffe, Sonja Vucen, Abina Crean

Cappa Publications

The conventional quality control techniques for identifying the denaturation of biopharmaceuticals includes sodium dodecyl sulfate-polyacrylamide gel electrophoresis for identifying fragmentation, ion exchange chromatography and isoelectric focusing for identifying deamidation, reverse-phase high-performance liquid chromatography (HPLC) for identifying oxidation, and size-exclusion HPLC for identifying aggregation. These stability assessments require essential processes that are destructive to the product tested. All these techniques are lab based and require sample removal from a sealed storage vial, which can breach the sterility. In this work, we investigate the heat- and surfactant-induced denaturation of an in-vial-stored model protein, bovine serum albumin (BSA), by analyzing its intrinsic fluorescence …

The Boozi Device’S Effect On Aroma Compounds In Distilled Spirits, Drew Budner, Lindsey Bell, Katherine Thompson-Witrick

Journal of the South Carolina Academy of Science

The BooZi is a commercially available flavor-modifying device that claims to remove the negative flavor agents (congeners) from a number of different types of distilled spirits and wines. SPME was utilized for the extraction of the volatile and semi-volatile compounds within each sample. The analysis of the compounds found in the samples following exposure to the BooZi device were analyzed using a GC-MS. The most significant changes regarding the aroma profile of the distilled spirits were noticeable following 96 hours of exposure. The BooZi device was shown to be effective in reducing the concentration of a number of compounds, including …

Electronic Transport Properties Of Spin-Crossover Polymer Plus Polyaniline Composites With Fe3O4 Nanoparticles, Esha Mishra, Waikiat Chin, Kayleigh A. Mcelveen, Thilini K. Ekanayaka, M. Zaid Zaz, Gauthami Viswan, Ruthi Zielinski, Alpha T. N'Diaye, David Shapiro, Rebecca Lai, Robert Streubel, Peter A. Dowben

Department of Chemistry: Faculty Publications

Adding Fe₃O₄ nanoparticles to composites of [Fe(Htrz)₂(trz)](BF₄) spin-crossover polymer and polyaniline (PANI) drives a phase separation of both and restores the molecular structure and cooperative effects of the spin-crossover polymer without compromising the increased conductivity gained through the addition of PANI. We observe an increased on-off ratio for the DC conductivity owing to an enlarged off state resistivity and a 20 times larger AC conductivity of the on state compared with DC values. The Fe₃O₄ nanoparticles, primarily confined to the [Fe(Htrz)₂(trz)](BF₄) phase, are ferromagnetically coupled to …

Post-Translational Modification Of Proteins Via Ambient Air Pollutants And Endogenous Reactive Species, Rachel Lauren Davey

Electronic Theses and Dissertations

Proteins can react with reactive oxygen species (ROS) and reactive nitrogen species (RNS) to form post-translational modifications (PTMs), which can affect protein structure and function. The formation of 3-nitrotyrosine (NTyr) and dityrosine (DiTyr) upon reaction of proteins with ROS/RNS are two common PTMs studied due to their stability and irreversibility, as well as their ability to enhance the allergenicity of pollen allergens upon formation. Many common techniques used to study the formation of these PTMs can reliably detect the PTMs but can only provide semi-quantitative information due to many assumptions and limitations. In Chapter 2 we present an analysis of …

Progress In 7sk Ribonucleoprotein Structural Biology, Momodou B. Camara, Amr M. Sobeh, Catherine D. Eichhorn

Department of Chemistry: Faculty Publications

The 7SK ribonucleoprotein (RNP) is a dynamic and multifunctional regulator of RNA Polymerase II (RNAPII) transcription in metazoa. Comprised of the noncoding 7SK RNA, core proteins, and numerous accessory proteins, the most wellknown 7SK RNP function is the sequestration and inactivation of the positive transcription elongation factor b (P-TEFb). More recently, 7SK RNP has been shown to regulate RNAPII transcription through P-TEFb-independent pathways. Due to its fundamental role in cellular function, dysregulation has been linked with human diseases including cancers, heart disease, developmental disorders, and viral infection. Significant advances in 7SK RNP structural biology have improved our understanding of 7SK …

Alternating Current Electrolysis For Amine Functionalization And Hydrogen Isotope Exchange, Disni Gunasekera

Wayne State University Dissertations

Electrochemical organic synthesis is experiencing a renaissance driven by the increasing demand for green chemistry and engineering in the pharmaceutical industry. Synthetic organic electrochemical methods can be divided into three types: anodic, cathodic, and paired electrolysis. Paired electrolysis, in which two desirable half-reactions are performedsimultaneously at the two electrodes, is mostly underdeveloped. However, paired electrolysis can be technologically significant because it not only improves energy efficiency by using both electrodes but also provides a unique reaction environment where two redox-opposite reactions of substrates take place in the same pot. A major challenge for paired electrolysis is that the difficulties associated …

Spatial And Temporal Varitations In Dissolved Calcium In The Kentucky Lake Watershed In Relation To Zebra Mussel Colonization, Kelsie Meystedt

Murray State Theses and Dissertations

Calcium is the fifth most abundant element on earth’s crust. Plants and animals require calcium for structure and intracellular metabolism. Recent studies have shown that dissolved calcium (Ca2+) freshwater ecosystems is of growing concern as the increasing concentrations of this element are implicated in altering the natural environment and biota. Elevated levels of dissolved calcium and sporadic re-emergence of an invasive species, namely zebra mussels (Dreissena polymorpha) in Kentucky Lake in the recent years served as a motivation for this study. The objective of this study was to determine spatial and temporal variations in dissolved calcium in selected streams, Kentucky …

Ongoing Fragmentation Of The Subducting Cocos Slab, Central America, Tu Xue, Diandian Peng, Kelly H. Liu, Jonathan Obrist-Farner, Marek Locmelis, Stephen S. Gao, Lijun Liu

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Fundamental to plate tectonics is the subduction of cold and mechanically strong oceanic plates. While the subducted plates are conventionally regarded to be impermeable to mantle flow and separate the mantle wedge and the sub slab region, isolated openings have been proposed. by combining new shear wave splitting measurements with results from geodynamic modeling and recent seismic tomography and geochemical observations, we show that the upper ~200 km of the Cocos slab in northern Central America is intensively fractured. the slab there is strong enough to produce typical arc volcanoes and Benioff Zone earthquakes but allows mantle flow to traverse …

Erratum: New Estimates Of The Magnitude Of The Sea-Level Jump During The 8.2 Ka Event, (Geology (2022), 50(1), (86–90), (10.1130/G49296.1)), Jonathan Obrist-Farner, Mark Brenner, Jeffery R. Stone, Marta Wojewódka-Przybył, Thorsten Bauersachs, Andreas Eckert, Marek Locmelis, Jason H. Curtis, Susan R.H. Zimmerman, Alex Correa-Metrio, Lorenz Schwark, Edward Duarte, Antje Schwalb, Etienne Niewerth, Paula Gabriela Echeverría-Galindo, Liseth Pérez

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

No abstract provided.

Reducing Disposable Plastic Waste From Protein Quantitative Assays, Justin Buiter

All Capstone Projects

Protein concentration quantification is important for many areas of biology and biochemistry. This quantification happens in large quantities in laboratories and needs to be done accurately and quickly. The Bradford assay is one of the most common ways of accomplishing this task (1). This assay relies on the binding of the protein and the Coomassie Blue G250 dye. The anionic blue form binds to the protein and has a maximum at 595 nm. This allows for accurate quantification by reading how much of the sample absorbs at 595 nm (2).

In 2014, it was estimated that 5.5 million tons of …

Methyl Isobutyrate Production Via Hydrogenation Of Methyl Methacrylate Derived From Pyrolysis Of Acrylic Plastic Waste, Ramzi Nasser Ahmed Saif

Chulalongkorn University Theses and Dissertations (Chula ETD)

According to zero waste and upcycling policy, this work aims to utilize waste polymethyl methacrylate (PMMA) to methyl isobutyrate (MIB) via hydrogenation over nickel (Ni) based catalysts supported on commercial zeolites: HY, H-Beta-27 (SiO2/Al2O3 = 27 by mole), H-Beta-40 (SiO2/Al2O3 = 40 by mole) and H-ZSM-5. The appropriate catalyst support was first screen by using MMA monomer as the substrate for hydrogenation. Under 30 bar initial H2 pressure (PH2) at 250 °C for 3 h, Ni/H-Beta-27 catalyst effectively promoted hydrogenation to achieve 85% MMA conversion with 56.2 wt% MIB yield because of its larger external surface area and pore size. …

Investigating Visinin-Like Protein 1 And Ubiquitinated Visinin-Like Protein 1 As Mild Traumatic Brain Injury Biomarkers, Yueming Wu

Theses and Dissertations--Chemistry

Traumatic brain injury (TBI) continues to be a significant cause of morbidity and mortality worldwide. Despite significant progress in understanding the complex pathophysiology of TBI, the underlying mechanisms remain poorly understood. The primary brain damage is acute and irreversible. However, secondary brain injuries often develop gradually over months to years, creating an opportunity for critical therapeutic interventions. In the past decade, research on TBI biomarkers has seen significant progress. This progress has been driven by the diverse nature of TBI pathologies and the challenges they present for evaluation, management, and prognosis. TBI biomarker proteins resulting from axonal, neuronal, or glial …

Deposited Cigarette Smoke As A Driver Of Oxidation And Partitioning Processes On Indoor Surfaces, April Hurlock

Honors Theses

Despite the large amount of time that individuals spend indoors during their lives, very little attention was paid to the chemistry that occurs on indoor surfaces until recently. Although not visible to the naked eye, physical and chemical processes, such as partitioning and oxidation, are occurring on virtually every indoor surface in a typical household. Indoor pollutants, ranging from skin oils to environmental cigarette smoke, drive a lot of these processes. The transformation of indoor surfaces by indoor pollutants can increase chemical exposure risks as new irritants or carcinogens can be introduced to the surfaces. In this thesis, I describe …

Comprehensive Analysis And Forensic Investigation Of Cyanide, Thiocyanate, And 2-Amino-2-Thiazoline-4-Carboxylic Acid In-Ante- And Postmortem Blood Utilizing Advanced Analytical Techniques, Abdullah Hamad Alluhayb

Electronic Theses and Dissertations

Cyanide (CN), present as cyanide anion (CN-) or hydrogen cyanide (HCN), is a deadly poison. The main mechanism of CN toxicity is blocking terminal electron transfer, leading to cellular hypoxia, cytotoxic anoxia, and potential death. Determining blood CN concen-trations along with its major metabolite, thiocyanate (SCN-), is crucial. A sensitive method for concurrent detection of CN and SCN- from human ante- and post-mortem blood via liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) analysis was devel-oped. The method involved active microdiffusion with chemical modification using naph-thalene-2,3-dicarboxaldehyde (NDA) and taurine, while monobromobimane (MBB) mod-ification was used for SCN-. The method showed good sensitivity for …

Method Development For The Quantification Of Heavy Metals In Biological Matrices And Its Application To Clinical And Environmental Samples, Michelle Catherine Gende

Dissertations

A three-fold approach was taken to develop a method for the detection of heavy metals in different matrices and had to be performed sequentially. The first was to develop a method capable of quantifying lead in complex matrices by graphite furnace atomic absorption (GFAA). The developed method needed to meet specific analytical requirements, namely, to be robust, sensitive, and accurate. Initially, four different sample preparation methods were explored for the quantification of lead using Escherichia coli (E. coli) as a sample matrix. The sample preparation procedures attempted were acidic dilution, matrix modification, conventional heating digestion, and microwave assisted acid digestion …

Developing Novel Femtosecond Time-Resolved Mass Spectrometry Techniques For Analysis Of Energetic Materials, Shane L. Mcpherson

Theses and Dissertations

Energetic materials and the unimolecular dissociation dynamics attributed to their initiation and subsequent bimolecular detonation have been a subject of interest for defense agencies such as the Department of Defense (DoD) for decades. The timescale in which these initial dynamics exist ranges from several picoseconds to dozens of femtoseconds, necessitating equally fast time-resolved experiments to capture and characterize these events. Our lab specializes in one such laser-based technique: femtosecond time-resolved mass spectrometry (FTRMS). FTRMS is an essentially nondiscriminatory pump-probe laser technique with nearly infinite modifications via pulse shaping, intensity, and wavelength modulation that can readily examine previously undefined dissociation pathways …

Uhplc/Ft-Ms Non-Targeted Screening Approach For Biomass Burning Organic Aerosol And Liquid Smoke As Biomass Burning Organic Aerosol Surrogate, D.M.R. Thusitha Dinusha Kumarihami Divisekara

Dissertations, Master's Theses and Master's Reports

Biomass combustion contributes a large amount of aerosol particles to the atmosphere impacting the climate system and human health. Identifying the molecular composition of biomass burning organic aerosol (BBOA) is challenging because of its complex nature. Liquid chromatography mass spectrometric non-targeted screening (NTS) methods provide a comprehensive analysis. However, the instrumentation and data analysis are challenging due to the extreme complexity of environmental samples. In the first part of this study, we implemented a new LC/FT-MS data processing approach by combining existing open-source data processing tools, MZmine2.53 and MFAssignR. The method's validity was checked using the standard polyacrylic acid (PAA) …

Exploring The Complementarity Of Measures Of Instructional Practices, Lu Shi, Robert M. Erdmann, Anthony Pellegrini, Victoria Johnson, Binh Le, Trina Popple, Zachary Nelson, Molly Undersander Gaston, Marilyne Stains

Department of Chemistry: Faculty Publications

The assessment of instructional quality has been and continues to be a desirable, yet difficult endeavor in higher education. The development of new teaching evaluation frameworks along with instruments to measure various aspects of teaching practices holds promise. The challenge rests in the implementation of these frameworks and measures in authentic settings. Part of this challenge is for instructors, researchers, and administrators to parse through and select a meaningful set of tools from the plethora of existing instruments. In this study, we aim to start clarifying the landscape of measures of instructional practice by exploring the complementarity of two existing …

Structural And Functional Modulation Of Metal-Organic Supercontainers (Moscs) And Their Applications In Supramolecular Catalysis, Shrijana Dc

Dissertations and Theses

Metal-organic supercontainers (MOSCs), a breakthrough development in our laboratory since 2012, have emerged as promising enzyme mimics, showcasing their prowess in encapsulating guest molecules and catalyzing confined chemical reactions. The intrigue surrounding MOSCs stems from their extraordinary traits, encompassing multiple binding domains, high stability, large surface area, tunable pore size, and structural modularity. Primarily comprising sulfonylcalix[4]arenes, divalent metal ions, and carboxylate linkers, MOSCs' quintessential architecture comprises both endo- and exo- nano-cavities, amenable to guest interaction, with geometry and functionality manipulation achievable through precise precursor selection. Nonetheless, early MOSC models exhibit limited reactivity, often necessitating more potent nucleophiles or electrophiles. This …