Analytical Chemistry Commons^™

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 …

Identification And Quantification Of Classic, Prescription, And Synthetic Opioids In Hair By Liquid Chromatography Tandem Mass Spectrometry (Lc/Ms/Ms), Natalia A. Platosz

Student Theses

The current use and misuse of synthetic and prescription opioids in the US has reached epidemic status. According to the US Department of Health and Human Services, every day more than 130 people in the US die after overdosing on opioids, and 2.1 million had an opioid use disorder in 2016. Hair is becoming an alternative matrix of increasing interest in forensic toxicology to investigate drug use and abuse patterns due to its long window of detection. The focus of this project was to develop and validate a method that simultaneously detects and quantifies 27 classic, prescription and synthetic opioids …

Comparison Of Three Analytical Techniques For General Characterisation Of Selected Algae And Cyanobacteria, Mohamed Iqbal Suhaina Nashath

Student Works (2020-2029)

Algae and cyanobacteria maintain the oxygenation of earth, and are utilised as biofuels, biofertilizers and nutrition feed. The characterisation of algae and cyanobacteria through conventional methods require technical expertise, laborious sample preparation, and moderately expensive instruments and reagents. Hence, in this study, selected bioanalytical techniques with minimal sample preparation were incorporated, to simplify the characterisation of algae and cyanobacteria. The objectives of this research were to study the phylogenetic relationship of the selected algae and cyanobacteria via the 23S plastid ribosomal ribonucleic acid (rRNA) and 18S rRNA biomarkers; to validate the presence of the microcystin synthetase (mcy) gene cluster encoding …

Functional Nanomaterials By Combining Aminooxy Chemistry And Iodine Activation At Momolayer Protected Clusters., Tirtha Raj Sibakoti

Electronic Theses and Dissertations

Aminooxy (-ONH₂) groups are most commonly known for their chemoselective reaction with carbonyl compounds (aldehydes/ketones) under mild reaction conditions. Aminooxy-based click chemistry is a versatile means of ligation as evidenced by broad application in material science, biology, biochemistry, analytical chemistry, and nanoscience. Our work exploits the facile reaction of aminooxy groups presented on the surface of gold (Au) or palladium (Pd) monolayer protected clusters (MPCs) with various aldehydes via oximation reactions, which form the robust oxime ether adducts. The functionalization of hexanethiolate-stabilized Au MPCs with a newly developed trifunctional amine-containing aminooxy alkanethiol ligand by thiol place-exchange affords aminooxylated …

Surface Chemistry And Surface Properties Of Energetic Nitrocellulose (Nc), Henry Grau

Seton Hall University Dissertations and Theses (ETDs)

This research describes an investigation into the wettability of nitrocellulose (NC), most importantly to nitroglycerin (NG), which are key components of formulations used to propel military ammunition. NG demonstrates complete wetting of NC and, overtime, NG sweats on the NC surface and leaks out. The leaking out of NG from the solid formulation is a known cause of fires and explosions resulting from storage. The origin of this research is inspired by the need to engineer a solution to leakage problems of energetic plasticizer in NC based propellant. While searching for a viable material for a specific application, we journeyed …

Analysis Of Petroleum Products For Forensic And Environmental Applications, Sarah Ghali, Sarah Porter

Virtual 2020 Spring Student Showcase for Research and Creative Inquiry

In both forensic and environmental applications, it is often important to identify ignitable liquid (IL) residues, to find a suspect or to clean up an oil spill. The ASTM method is commonly used; the extraction methods vary, but the data collection is the same. The instrument used in the ASTM method is gas chromatography mass spectroscopy (GC-MS), which allows a visual identification of the IL contaminating the sample. In this study, the use of Fourier transform infrared spectrometry (FTIR) was used in conjunction with chemometric analysis. Samples were prepared were to simulate an oil spill in natural waters. Two chemometric …

Analysis Of Phenolic Compounds In Moroccan Olive Oils By Hplc, Hannah Meyls, Sarah Porter

Virtual 2020 Spring Student Showcase for Research and Creative Inquiry

Five extra virgin olive oils collected from farms in Morocco were analyzed for phenolic compounds. To complement these data, the chemical composition of the olive oils were analyzed by high-performance liquid chromatography. Several phenolic compounds were identified and quantified in the olive oils. Specifically, levels of oleuropein and luteolin were quantified in the low mg/kg range, and qualitative comparisons were made between the oil samples for tyrosol, vanillic acid, and apigenin. To compare extraction efficiency of different extraction solvents, methanol and DMF were used.

Surveillance Of Microplastic Pollution In Central Virginia Freshwater Ecosystems, Alexandra Reddy

Senior Honors Theses

Aquatic organisms often mistake microplastic particulates (MP) as food and inadvertently ingest the particulates, which can biomagnify through the food chain. While MP ingestion is well-researched in the marine environment, little is known about microplastics in freshwater  ecosystems. This project explores MP occurrence in an ecologically significant freshwater invertebrate: crayfish. Crayfish from two Central Virginia streams are collected to identify MP in the digestive tracts and gill filaments, and characterize the MP using analytical chemistry techniques. It was determined that MP were present in the digestive tracts and gill filaments of crayfish collected from both streams, and that MP frequency …

Extensible Interface For A Compact Spectrophotometer For Teaching Molecular Absorption In The Undergraduate Laboratory, Edward Navarre

SIUE Faculty Research, Scholarship, and Creative Activity

A simple computer interface for controlling a compact spectrograph for use as a spectrophotometer in an undergraduate teaching laboratory was developed. The project was implemented on a Raspberry Pi computer which permits the integration of a light source into the software. The interface was written in Python to facilitate modification by the user and because of its compatibility with several computing platforms. An implementation of the project in Linux on a Raspberry Pi computer is described.

Phosphorus Nmr And Its Application To Metabolomics, Paula Evans, Fatema Bhinderwala, Robert Powers, Martha Morton, Thomas Smith

UCARE: Research Products

Stable isotopes are routinely employed by NMR metabolomics to highlight specific metabolic processes and to monitor pathway flux. 13C-carbon and 15N-nitrogen labeled nutrients are convenient sources of isotope tracers and are commonly added as supplements to a variety of biological systems ranging from cell cultures to animal models. Unlike 13C and 15N, 31P-phosphourous is a naturally abundant and NMR active isotope that doesn’t require an external supplemental source. To date, 31P NMR has seen limited usage in metabolomics because of a lack of reference spectra, difficulties in sample preparation, and an absence of two-dimensional (2D) NMR experiments. But, 31P NMR …

Quantification Of Vitamin B12 In Two Cricket Species, Haley Smeltz

Student Scholar Showcase

Entomophagy, or the eating of insects, has been practiced in the eastern world for centuries, however it is currently overlooked in the western nations. Studies have shown that insects, such as crickets, contain high levels of protein and minerals, however vitamin content is rarely studied. This study aims to quantify the vitamin B₁₂ content in two cricket species, the common house cricket (Acheta domesticus) and the banded cricket (Gryllodes sigillatus). The vitamin B₁₂ content of both cricket species will be quantified using reverse-phase high performance liquid chromatography (RP-HPLC). Prior to RP-HPLC analysis, all the …

Design, Construction, And Characterization Of A Low-Cost Spectrometer With Interchangeable Parts, Jack Godek

UNO Student Research and Creative Activity Fair

A low-cost spectrometer was designed for the purpose of teaching spectroscopy. The spectrometer can be built by the student and contains interchangeable pieces such as slit width, grating, and lenses. This will allow the student to understand how changing these variables effects resolution. The spectrometer was constructed from PVC pipe, a plastic electrical box, and a USB webcam. The actual resolution of the spectrometer is close to the theoretical value, depending on which lens and grating is used. In addition, an extra piece can be added that allows absorption spectra to be collected. Having the student piece together the spectrometer …

Optimization Of A Digital Ion Trap To Perform Isotope Ratio Analysis Of Xenon For Planetary Studies, Timothy Vazquez

USF Tampa Graduate Theses and Dissertations

Ion trap mass spectrometers present a powerful analytical tool which not only enables mass spectrometric determination of analyte species but also has the added feature of being able to act as an ion storage device. As a mass spectrometer, ion traps can achieve a reasonable mass range with flexible mass resolution while boasting a considerably smaller footprint when compared to conventional time-of-flight or magnetic sector instruments. Due to their smaller geometries, high-pressure tolerance, and ability to perform tandem mass spectrometry, ion trap mass spectrometers are ideal candidates for portable applications such as deployment to another planetary body. While ideal candidates …

Evaluation Of The Overall Binding Of Acetohexamide And Tolbutamide With Methyl Glyoxal-Modified Hsa By High-Performance Affinity Chromatography, Ashley G. Woolfork, David S. Hage

Department of Chemistry: Dissertations, Theses, and Student Research

High performance affinity chromatography (HPAC) was used in a zonal competition format to investigate the overall binding of two sulfonylurea drugs with modified human serum albumin (HSA). The in vitro modifications of this protein that were examined included glycation, as occurs in the presence of elevated glucose levels during diabetes, and the formation of advanced glycation end-products (AGEs) due to the reaction of HSA with methylglyoxal (MGo). The sulfonylurea drugs acetohexamide and tolbutamide, which are used to treat type II diabetes, were each injected onto 10 mm x 2.1 mm i.d. affinity microcolumns that contained normal HSA and HSA modified …

Analysis Of Hydroxychloroquine Interaction With Serum Proteins By High Performance Affinity Chromatography, Kyungah Suh, Sadia Sharmeen, David S. Hage

Department of Chemistry: Dissertations, Theses, and Student Research

Personalized medicine or precision medicine has been an emerging market for better treatments of patients under varying physiological conditions.To improve the development of personalized medicine, a higher understanding of drug-protein binding between serum transport proteins and the unbound form of pharmaceuticals is needed. Human Serum Albumin (HSA) and Alpha1-acidglycoprotein (AGP) play a crucial role in pharmacokinetics as they are two most abundant transport serum proteins in body circulatory system. Inter-individual variabilities of serum proteins, such as the physiological condition of patients, have been believed to alter the drug-serum protein binding. Fig. 1 shows an example of the cause of inter-individual …

Electrochemical Impedance Spectroscopy For Electrocatalytic Interfaces And Reactions: Classics Never Die, Jun Huang

Journal of Electrochemistry

This review article recapitulates electrochemical impedance spectroscopy (EIS) studies in the field of electrocatalysis. The history of this specialized field, ranging from the beginning of the twentieth century to now, is outlined. We then chronicle milestones of the impedance theory. Special emphases are put on the Dolin-Ershler model, the prevailing model for analyzing adsorption impedance data. Afterwards, we narrow into a very specific and fundamental topic, the double-layer capacitance at platinum (Pt) single crystals. We discuss the challenges in experimentation and theoretical understanding thereof. We cast doubts into the validity of using the Dolin-Ershler model to obtain the double-layer capacitance …

In-Situ Raman Spectroscopic Study Of Electrochemical Reactions At Single Crystal Surfaces, Min Su, Jin-Chao Dong, Jian-Feng Li

Journal of Electrochemistry

Since the 1970s, in-situ spectroscopy (Raman, infrared, etc.) has been used to systematically study the electrochemical interfacial reactions which can provide more information about surface reactions and reveal the mechanisms from microscopic view due to its excellent surface sensitivity and energy resolution. With the development of nano-technology, surface-enhanced Raman scattering effect spectroscopy has made rapid progress. Recently, the emergence of SHINERS provides a good in-situ spectroscopic technique for the study of catalytic reactions on single crystal model electrodes with deterministic surface structure. In this paper, we have summarized the application of SHINERS in the study of …

Surface Reservoirs Dominate Dynamic Gas-Surface Partitioning Of Many Indoor Air Constituents, Chen Wang, Douglas B. Collins, Caleb Arata, Allen H. Goldstein, James M. Mattila, Delphine K. Farmer, Laura Ampollini, Peter F. Decarlo, Atila Novoselac, Marina E. Vance, William W. Nazaroff, Jonathan P.D. Abbatt

Faculty Journal Articles

Human health is affected by indoor air quality. One distinctive aspect of the indoor environment is its very large surface area that acts as a poorly characterized sink and source of gas-phase chemicals. In this work, air-surface interactions of 19 common indoor air contaminants with diverse properties and sources were monitored in a house using fast-response, on-line mass spectrometric and spectroscopic methods. Enhanced-ventilation experiments demonstrate that most of the contaminants reside in the surface reservoirs and not, as expected, in the gas phase. They participate in rapid air-surface partitioning that is much faster than air exchange. Phase distribution calculations are …

Assessment Of Soil Protein And Refractory Soil Organic Matter Across Two Chronosequences Of Newly Developing Marshes In Coastal Louisiana, Usa, Stuart Alexander Mcclellan

LSU Doctoral Dissertations

The impacts of sea-level rise and hydrologic manipulation are threatening the stability of coastal marshes throughout the world, thereby increasing the potential for re-mineralization of soil organic matter (SOM) in these systems. Such threats have prompted marsh restoration efforts, particularly in coastal Louisiana, yet it is unclear how the slowly decomposing (refractory) and quickly decomposing (labile) fractions of SOM may be differentially affected by different approaches to marsh restoration. Additionally, otherwise labile compounds may accumulate in the soil via a range of protective mechanisms, including rapid burial and association with organic compounds that are thought to enhance soil aggregation, such …

Yeast Copper Proteins And Reactive Oxygen Species In Effecting Lifespan, Megan Bestwick

Post-Grant Reports

Mitochondria are essential organelles in most eukaryotic cells because of their role in metabolism and the production of ATP by the oxidative phosphorylation (OXPHOS) pathway, as well as other key cellular processes. Metal cofactors, such as copper (Cu) and iron (Fe), are incorporated into OXPHOS protein complexes of yeast located within the inner membrane of the mitochondria. Misincorporation or modulation of these available metals in mitochondrial enzymes leads to the production of reactive oxygen species (ROS). ROS are reactive molecules containing oxygen such as peroxides, superoxide, and hydroxyl radicals. Yeast are a good model for studying aging and the effect …

Force Field Development Of Β-Lactam Class Antibiotics, Trevor Heinzmann

SMU Journal of Undergraduate Research

Molecular dynamics (MD) simulation is a computational chemistry technique used to observe how a molecular system behaves as time passes. MD is based on solving Newton’s equations of motion. This requires the use of force fields to describe the potential energy function of each different molecule type in molecular system. In order to develop a force field, charges, bonds, angles, and dihedrals must be parameterized to fit quantum mechanics (QM) data. By basing the force field on QM data, MD simulations have higher accuracy while still using the low computational cost of molecular mechanics. This project focuses on developing well-fit …

Study Of Reaction Dynamics Of Protonated/Deprotonated And Radical Cations Of Guanine In Nucleobases And Nucleosides: Singlet Oxygen Oxidation, C8-Water Addition, Cross-Linking With Lysine And Base-Pair Dissociation, Yan Sun

Dissertations, Theses, and Capstone Projects

Among the four DNA nucleobases, guanine (G) has the lowest oxidation potential and represents a preferential target for oxidation and ionization. This leads to the formation of guanine radical cation (G^•+) in various oxidative environments. Of the biologically relevant oxidants, electronically excited singlet oxygen (¹O₂) exclusively damages the guanine bases and gives rise to mutagenesis, DNA-protein cross-linking and cellular death. Combining our home-made electrospray ionization (ESI) guided-ion-beam tandem mass spectrometer, with reaction potential surface calculations and kinetics modeling, five projects have been accomplished as described below.

In project 1, the reactions of deuterated water …

Development Of An Electrochemical Immunosensor For Direct Detection Of Acrylamide In Food Samples, Pei Ying Lau

Student Works (2020-2029)

Acrylamide, a potential carcinogen which is mainly found in plant-based food such as potato chips, French fries, bread, biscuit, coffee and coco, after undergoing heating process at temperature above 120°C. The permissible maximum intake of acrylamide is 2.6 μg kg−1 of body weight per day to prevent cancer risk. Due to its neurotoxicity and carcinogenicity, a rapid detection method for acrylamide is strongly needed in food safety concern. Herein, a sample pre-treatment free electrochemical immunosensor was developed based on a displacement assay. In a displacement assay format, an antibody is initially bound to the surface immobilized hapten (analyte analogue) and …

Investigation On The Potential Of Dried Blood Stain For The Detection Of Amphetamine Type Stimulants By Enhanced Methods Of Liquid Chromatography Tandem-Mass Spectrometry, Ahmad Zubaidi Fathiah

Student Works (2020-2029)

The investigation on the potential of dried blood stain for Amphetamine Type Stimulants (ATS) has been divided into four major parts, from which independent conclusions are drawn. The first part is the development and validation of a novel method for the simultaneous determination of the drugs using liquid chromatography with electrospray ionization tandem mass spectrometer (LC-ESI-MS/MS). The method is enhanced from normal Multi-Reaction Mode (MRM) to Multi-Reaction Mode-Enhanced Product Ion Mode- Multi-Reaction Mode 3 (MRM-EPI-MRM3) and tested in whole blood specimens (WBS), dried blood stain (DBS) and urine specimens as well as applied to real forensic cases in Malaysia. The …

Differential Mobility Spectrometry-Mass Spectrometry (Dms-Ms) For Forensic And Nuclear-Forensic Applications, Ifeoluwa Ayodeji

USF Tampa Graduate Theses and Dissertations

In forensics and nuclear-forensics, the current lab-based analytical technique employed can be laborious, time consuming, and less suitable for in-situ and real time screening. However, it is important to develop fast and fieldable instrumental technique, without a tradeoff for its high throughput, for drug screening and radionuclear analysis. The underlying factors to be considered in the instrument development ranges from: high potency of samples, even at very low concentration; complex nature of samples in the surrounding environment; real-time chemical composition variation; and instrument size, weight and power (SWAP) consideration. Differential mobility spectrometry (DMS), also known as field asymmetric waveform ion …

Resolving The Puzzle Of Single-Atom Silver Dispersion On Nanosized Γ-Al2o3 Surface For High Catalytic Performance, Fei Wang, Jinzhu Ma, Shaohui Xin, Qiang Wang, Jun Xu, Changbin Zhang, Hong He, Xiao Cheng Zeng

Department of Chemistry: Faculty Publications

Ag/γ-Al2O3 is widely used for catalyzing various reactions, and its performance depends on the valence state, morphology and dispersion of Ag species. However, detailed anchoring mechanism of Ag species on γ-Al2O3 remains largely unknown. Herein, we reveal that the terminal hydroxyls on γ-Al2O3 are responsible for anchoring Ag species. The abundant terminal hydroxyls existed on nanosized γ-Al2O3 can lead to single-atom silver dispersion, thereby resulting in markedly enhanced performance than the Ag cluster on microsized γ-Al2O3. Density-functional-theory calculations confirm that Ag atom is mainly anchored by the terminal hydroxyls on (100) surface, forming a staple-like local structure with each Ag …

Pine Rosin As A Toxic Cannabis Extract Adulterant, Jiries Meehan-Attrash, Robert Strongin

Chemistry Faculty Publications and Presentations

Pine rosin (colophony) has been identified as a new adulterant in cannabis oil. Its inhalation toxicity poses a significant health concern to users. For example, pine rosin fumes are released during soldering, and have been cited as a causative agent of occupational asthma. Symptoms also include desquamation of bronchial epithelium, which has also been observed in EVALI patients. The sample analyzed herein was acquired from a cannabis industry source, also contains medium chain triglycerides and oleamide, the latter of which is a hypnotic that is commonly found in the synthetic marijuana product Spice, or K2. A combination of NMR and …

Methods Of Making And Using Lignin Derivatives, Mark Alan Helle, Chin Li Cheung

Department of Chemistry: Faculty Publications

Materials and methods for preparing reactive lignin and for preparing a bio-based adhesive are described herein.

This disclosure generally relates to methods of making and using reactive lignin. This disclosure also generally relates to methods of making and using bio-based adhesives. Lignin is the second most abundant natural polymer behind cellulose, yet lignin has very little commercial value despite years of research. Lignin is one of the major components of the cell wall in wood and other plant based materials such as hemp or crop wastes. It is produced in enormous quantities each year, primarily as a by-product in the …

A Possible Unaccounted Source Of Atmospheric Sulfate Formation: Amine-Promoted Hydrolysis And Non-Radical Oxidation Of Sulfur Dioxide, Shixian Wang, Xiao Cheng Zeng, Hui Li, Joseph S. Francisco

Xiao Cheng Zeng Publications

Numerous field and laboratory studies have shown that amines, especially dimethylamine (DMA), are crucial to atmospheric particulate nucleation. However, the molecular mechanism by which amines lead to atmospheric particulate formation is still not fully understood. Herein, we show that DMA molecules can also promote the conversion of atmospheric SO₂ to sulfate. Based on ab initio simulations, we find that in the presence of DMA, the originally endothermic and kinetically unfavourable hydrolysis reaction between gaseous SO₂ and water vapour can become both exothermic and kinetically favourable. The resulting product, bisulfite NH₂(CH₃)₂⁺ ∙ HSO …

Iron In Urban Air Pollution, Joseph R. Salazar

Electronic Theses and Dissertations

The processes by which iron is solubilized are largely unknown. There are three hypotheses on how iron is soluble: 1) iron is thought to undergo an acid based solubilization process, 2) iron undergoes an oxidation/reduction process and reduces iron(III) to the more soluble iron(II), and 3) iron is bound to organic molecules, which solubilizes it. The 3 hypotheses on iron water-solubilized are explored by presenting two individual studies.

The first study investigates iron directly from car exhaust. Exhaust particles were collected from 32 vehicles. Iron solubility in these samples ranged from 0%-82% with the average iron solubility being 30%. X-ray …