Analytical Chemistry Commons^™

Enantioselectivity Of The Photochemical Continuous-Flow Isomerization Of Humulones, Gregory M. Giovine, Trevor Smith, Bruce Hamper

Undergraduate Research Symposium

Humulones, the primary natural product present in the historically significant hop flower, represent a largely unexplored candidate for structure-based pharmaceutical design.  Showing promising biological activity as an anti-bacterial and anti-inflammatory agent, humulones are of interest both for their bioactive properties and for their long-established tolerability and natural abundance.  Humulones undergo a characteristic isomerization reaction, where the six-membered substituted phloroglucinol ring contracts to a five-membered ring isohumulone, under a variety of conditions, including those enabled by brewing conditions (thermal, metal-catalyzed) and by exposure to UV light.  Optimization of the photocatalyzed isomerization of n-humulone to n-isohumulone in flow conditions resulted in a …

Development Of Ultrafast Protein Digestion And Standards Free Quantitation Methods For Mass Spectrometric Analysis, Praneeth Ivan Joel Fnu

Dissertations

A wide variety of biologically important molecules, such as enzymes, antibodies, hormones, transporters and receptors are proteins by composition and they play key roles in biological functions such as cellular regulation, communication, metabolism and physiological function. Protein dysfunctions and abnormalities are associated with numerous diseases, making proteins critical targets for understanding disease mechanisms and developing therapeutic interventions. Protein-based therapeutics such as monoclonal antibodies, hormones and vaccines gained popularity due to their high specificity, efficacy, and ability to treat complex diseases that are often difficult to address with small-molecule drugs.

Given the important role of proteins in a variety of biological …

Extracting Aromatic Compounds From Dehydrated Rose Buds, Lana Sheridan

Discovery Day - Daytona Beach

Eugenol (C10H12O2), methyl eugenol (C11H14O2), and 2-phenylethanol (C8H10O) are chemically aromatic, natural compounds commonly present in various botanical sources and essential oils. Structurally, eugenol is a methoxyphenol bearing an allyl side chain; its methyl ether derivative, methyl eugenol, shares a similar framework but features a methoxy group replacing the free phenolic hydroxyl group found in eugenol. 2-Phenylethanol is an aromatic alcohol comprised of a benzene ring linked to an ethanol moiety. The objective of this project was to isolate and characterize these compounds in dried rose buds using distillation followed by chromatographic and spectrometric analysis. For the experiment, a steam …

Steam Distillation Star Anise, Makayla Maso, Kiara Maso

Discovery Day - Daytona Beach

Star anise (Illicium verum) contains several volatile organic compounds responsible for its characteristic aroma, including trans-anethole, estragole, limonene, and linalool. These compounds differ in structure and chemical properties, which influence their behavior during isolation and analysis. Trans-anethole and estragole are classified as aromatic phenylpropene derivatives that contain benzene rings and ether functionalities. In contrast, limonene and linalool are non-aromatic terpenes, with linalool additionally possessing an alcohol functional group. These compounds are widely utilized as flavoring agents and fragrance components, while terpenes such as limonene and linalool are also commonly employed as solvents and in formulation chemistry due to their volatility …

Extraction Of Cedarwood Essential Oils Via Steam Distillation, Forrest Dohner

Discovery Day - Daytona Beach

Many natural materials, including pine and eucalyptus, produce distinct scents due to the presence of volatile organic compounds. In cedarwood, this aroma arises from a combination of aromatic molecules, which are organic compounds containing conjugated carbon ring systems that interact with olfactory receptors. Specifically, cedarwood contains three primary compounds responsible for its scent: cedrol, cedrene, and thujopene. The objective of this experiment was to extract these essential oils from cedarwood and identify their chemical composition. Steam distillation was used to isolate the volatile components by passing steam through the cedarwood, causing the essential oils to vaporize at temperatures below their …

Production And Analysis Of Lavender Essential Oil: Extraction, Composition, And Applications, Mary Zoeller

Discovery Day - Daytona Beach

Steam distillation was performed to extract essential oil from lavender and analyze its chemical composition. Lavender is known to contain several compounds such as linalool, terpinen-4-ol, and linalyl acetate, which contribute to its characteristic aroma and biological activity. The purpose of this experiment was to isolate these compounds without decomposition and identify them using gas chromatography–mass spectrometry (GC-MS). Approximately 14.851 g of lavender was heated with water to generate steam, which carried the volatile compounds into a condenser where the vapor was cooled and collected. The distillate was transferred to a separatory funnel to isolate the organic layer from the …

Steam Distillation Of Jasmine, Mikayla Hulvey, Meliah Martin

Discovery Day - Daytona Beach

This experiment aimed to isolate various components, including benzyl acetate, linalool, indole, and farnesene, from jasmine buds. The functional groups include an ester in benzyl acetate, an alcohol in linalool, an amine in indole, and alkenes in farnesene. Jasmine buds were combined with distilled water and steam distilled using a standard distillation apparatus. The distillate, containing hydrosol and trace amounts of essential oil, was then collected for extraction using methyl tert-butyl (MTBE) for a liquid-liquid extraction. The organic layer was then separated, washed using brine, dried over anhydrous sodium sulfate, and then transferred for later analysis. The essential oil obtained …

Analysis Of Terpenes In Cannabis Flowers Using Gas Chromatography Via Headspace-Solid Phase Microextraction (Hs-Spme), Hannah I. Bergner

Forensic Science Master's Projects

As cannabis commercialization grows, rigorous profiling of cannabinoids, terpenes, and chemical contaminants is legally required for industry standardization and consumer safety. Terpenes are highly volatile components that dictate the unique aromatic profiles and therapeutic properties of cannabis via receptor pathways. This project focused on a gas chromatography-flame ionization detector/mass selective detector (GC-FID/MSD) combined with headspace-solid phase microextraction (HS-SPME) sampling to analyze terpenes present in four cannabis samples. Cannabis samples were tightly sealed in vials (10 mL) and heated to vaporize terpenes in the headspace above the samples, followed by the extraction of the vaporized terpenes using a polydimethylsiloxane (PDMS)-coated SPME …

Investigation Of Warfarin–Human Serum Albumin Binding By Ultrafast Affinity Extraction Using Single- And Dual-Column Affinity Microcolumn Systems, Samiul Alim

Department of Chemistry: Dissertations, Theses, and Student Research

This dissertation examined the interaction of warfarin with human serum albumin (HSA) by using affinity chromatography, with particular emphasis on ultrafast affinity extraction (UAE) and affinity microcolumns. HSA affinity supports were prepared by immobilizing HSA onto diol-bonded silica via Schiff base chemistry and used to prepare affinity microcolumns for chromatographic studies under physiological-like conditions at pH 7.4 and 37.0 °C. UAE studies were performed to investigate the effects of residence time, flow rate, and column configuration on the measured apparent free fraction of warfarin and on the calculated apparent binding parameters. The results showed that the measured apparent free fraction …

The Influence Of Fermentation Duration And Secondary Fermentation Conditions On The Bioactive Compound Profile Of Kombucha, Jordan Vereen

Honors Theses

Kombucha is a fermented sweet tea produced using a symbiotic culture of bacteria and yeast (SCOBY) and has gained widespread popularity due to its proposed health benefits. Kombucha has been studied to understand these advantages in cardiovascular support, improved metabolism, increased antioxidant effects, enhanced antimicrobial properties, and even potentially slowing the progression of certain diseases. Despite its increasing popularity, the way in which the specific bioactive compounds responsible for these effects and the fermentation conditions that influence their production remain unclear. The present study, conducted in collaboration with Dr. Budner, focuses on quantifying bioactive compounds in kombucha to better understand …

Interview With Orca Award Winner David Hage, Unl Chemistry; Drug-Protein Interactions, Mark Griep, David Hage

UNL ORCA Interview Series

Prof. David Hage was awarded the ORCA in 2018. He was born in La Crosse, Wisconsin, and earned a bachelor’s in chemistry at the University of Wisconsin in La Crosse. Next, he earned a doctorate from Iowa State University and did postdoctoral work at the Mayo Clinic in Rochester, Minnesota. In 1989, he joined UNL as an assistant professor of chemistry and quickly rose through the ranks. He has won many awards and, for the past 13 years, has been the James Hewet University Professor of Chemistry. Allow me to share some remarkable facts about Dave before we get into …

Monosaccharide Binding To Synthetic Carbohydrate Receptor Microarrays, Milan A. Shlain

Dissertations, Theses, and Capstone Projects

Chapter 1: A glycan detection platform comprised of synthetic carbohydrate receptors (SCRs) immobilized onto polymer brushes was prepared. SCR043, an alkene-containing SCR, was incorporated into grafted-from polymer brushes using hypersurface photolithography, resulting in microarrays of SCR043-functionalized polymer brushes, where brush height (h) and SCR grafting density (Γ) is controlled precisely at each feature in the array. The influence of h and Γ on the binding to five fluorescently labelled monosaccharides – α-glucose (α-Gluc-FL), α-galactose (α-Gal-FL), α-mannose (α-Man-FL), β-glucose (β-Gluc-FL), and β-galactose (β-Gal-FL) – in aqueous buffer …

Absolute Quantification And Identification Of Rna From Rna-Lipid Nanoparticles Using High Resolution Mass Spectrometry, Jason C. Funderburk

Theses and Dissertations

RNA therapeutics are a rising drug category with potential use for a range of conditions encompassing infectious diseases to therapies for cancer, diseases, and genetic disorders. RNA-lipid nanoparticles (RNA-LNPs) are the prominent delivery method for these therapeutics approved products include mRNA vaccines and polyneuropathy treatments. The emergency use authorizations and orphan drug status of current RNA-LNP drugs has allowed approval without finalization of the regulatory analytical procedures for quality monitoring. The objective of the study was to develop an LC-MS assay to simultaneously measure identity and concentration of two therapeutically relevant intact RNA constructs extracted from RNA-LNPs to enhance quality …

Photo And Spatial Control Of Rna Structures And Functions: Exploring Positional Effects And Photo-Responsiveness Of Azobenzene Modified Nucleotides, Jinxi Du

Electronic Theses & Dissertations (2024 - present)

RNA molecules perform many important biological functions by forming complex three-dimensional structures stabilized by base pairing, tertiary interactions, and metal ion coordination. Because RNA function depends strongly on its structure, methods that allow reversible control of RNA conformation and activity are important for understanding RNA behavior and for potential therapeutic applications. However, achieving reversible and site-specific control of RNA structure, especially at the single-nucleotide level, remains challenging. In this dissertation, I developed and applied azobenzene-modified nucleotides as a chemical tool to enable optical and spatial control of RNA structure and function.

The first part of this dissertation focuses on establishing …

Physicochemical, Pharmacognostic Standardisation And Phytochemical Analyses Of The Homoeopathic Drug Justicia Adhatoda, Bibaswan Biswas, Satish Patel, Digvijay Verma, Satyajit Maity, Shilpi Singh, Paulami Majumdar, Narasimha Kumar Gv

Indian Journal of Research in Homoeopathy

Background: Justicia adhatoda (J. adhatoda), also well known as Vasaka in India is a medicinal plant chiefly used to treat respiratory ailments in traditional and alternative medical systems. Objective: This study aimed to establish the physicochemical, pharmacognostic, and phytochemical standardisation parameters of the drug. The study involved the measurement of physicochemical parameters and chemical profiling of the raw drug. The chemical characteristics of the in-house mother tincture (prepared from in-house raw drug) and commercial mother tinctures available in India were also evaluated to assess the quality of commercially available mother tinctures. Materials and Methods: The present study …

Suitability Of Mobile Phase Recycling For Methylxanthine Quantification In Coffee Samples Using Hplc, Kaitlin O’Keeffe, Marcos Mariano, Brian Murphy

SURE Journal: Science Undergraduate Research Experience Journal

Caffeine, theobromine and theophylline fall under a drug class known as methylxanthines. These three compounds are of major interest in the food industry due to their presence in popular foods and beverages such as tea, coffee, and chocolate. As these compounds can cause physical and mental stress at high dosages, their quantification is essential to ensure product safety and quality. Here, we describe an eco-friendly HPLC method developed to quantify the amount of these analytes in coffee samples sourced across the SETU Waterford, Cork Road campus. Using an isocratic mixture of water and methanol, a mobile phase recycling approach was …

Spilling The Tea: Effects Of Uv Disinfection On Bioactive Compounds In South African Rooibos Tea, Sora Ghanem, Leah Ankiah, Yusra Ahmed

Student Scholar Symposium

This study investigated the effects of ultraviolet (UV) light disinfection on key bioactive flavonoid compounds in rooibos tea (Aspalathus linearis). There is an interest in non-thermal food preservation technologies, and UV treatment offers potential advantages for beverage processing. However, concerns exist regarding possible degradation of health-promoting compounds during treatment. Rooibos tea samples were subjected to five UV exposure intensities (0, 25, 50, 75, and 100 mJ/cm²), and concentrations of four major flavonoids (aspalathin, orientin, vitexin, and rutin) were measured using high performance liquid chromatography (HPLC). Surprisingly, most flavonoids showed stability or slight concentration increases at higher UV doses. Aspalathin concentrations …

Unveiling Hidden Hazards: A Complementary Approach To Affordable Non-Destructive Heavy Metal Detection, Mario Faragalla, Gulsin Barwari, Makenzie Brinkoeter, Eimy Lozano-Fuentes, Isabelle Riera

Student Scholar Symposium

History has bestowed upon us vast treasures, with the Victorian Era offering a wealth of gifts, such as vibrant art and even secrets preserved in books of this period. However, concealed within the pigments that bring these works to life lie heavy metals. Not only do they pose significant health risks, but they can also be found within these pieces centuries later. Intrigued by the Winterthur project, Beaman librarians, Jan Cohu and Kayla Rutledge, discovered that our library housed some of these Victorian Era books. From there, the Beaman staff sent an inquiry to the chemistry department and Dr. Weinstein-Webb …

Health Implications Of Heavy Metal Contamination In Commercially Available Deodorant And Antiperspirant Products Sold In Benghazi, Libya, Maysson Yaghi, Khaled Elsherif

Al-Bahir

The extensive usage of deodorants and antiperspirants raises concerns about the potential health risks posed by heavy metal content. This study quantified the levels of five heavy metals: Aluminum, Zirconium, Lead, Cadmium, and Chromium in 22 commercial products widely used in Benghazi, Libya, and assessed the associated health risks. Samples, categorized into gel, stick, and roll-on formulations, were analyzed using iCAP TQ ICP-MS. Al and Zr showed the widest concentration ranges, reflecting their intentional use as active ingredients. Al levels ranged from trace amounts (0.032 mg/kg) up to a maximum of 99.10 mg/kg, while Zr was found exclusively in gel …

Modified 2-Quinolinones For Photocatalysis: The Fluorescence Quantum Yield (Φf) Of Novel 2-Quinolinone Derivatives, Reggina Moreno Trevino, Graham Griffin

DePaul Discoveries

The photophysical properties of novel 2-quinolinone derivatives were examined to evaluate their potential as photocatalysts using fluorescence and UV-Vis absorbance spectroscopy. The fluorescence quantum yields were determined via the relative comparative method, using target absorbance values at a specific wavelength to prepare solutions and comparing these measurements to the reference molecule carbostyril-124. Molar absorptivity values were also calculated to assess the light absorption properties for each compound. Among the derivatives, PAV-3 presented with the highest molar absorptivity and fluorescence quantum yield values (ε= 15297.3 M-1 cm-1, ΦF= 17.1%), while PAV-5 showed the lowest (ε= 4796.2 M-1 cm-1, ΦF= 2.3%). The …

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 …

Mechanistic Investigation Of Ring-Opening Polymerization Of Polycaprolactone Using Tin(Ii) Catalysts: Ligand Effects And Biomedical Applications, Eva-Larue M. Barber

Honors Scholar Theses

This research explores the mechanistic aspects of ring-opening polymerization (ROP) of ε-caprolactone (CL) to produce polycaprolactone (PCL), a biodegradable polymer widely used in biomedical applications. The study investigates how light exposure and catalyst concentration influence polymerization efficiency, using tin(II) 2-ethylhexanoate [Sn(Oct)₂] as the catalyst in a non-polar toluene solvent at 90 °C. Reactions were conducted under either ambient light or black light bulb (BLB) illumination, with monomer-to-catalyst ratios of 1:1 and 200:1.

Proton nuclear magnetic resonance (¹H NMR) spectroscopy was used to analyze conversion efficiency by tracking the disappearance of monomer signals and appearance of characteristic PCL peaks. Results revealed …

A Bland–Altman Comparison Of The Lead Care® System And Inductively Coupled Plasma Mass Spectrometry For Detecting Low-Level Lead In Child Whole Blood Samples, Christina Sobin, Tanner Schaub, Natali Parisi, Eva De La Riva

Departmental Papers (PH)

Chronic childhood lead exposure, yielding blood lead levels consistently below 10 μg/dL, remains a major public health concern. Low neurotoxic effect thresholds have not yet been established. Progress requires accurate, efficient, and cost-effective methods for testing large numbers of children. The LeadCare® System (LCS) may provide one ready option. The comparability of this system to the “gold standard” method of inductively coupled plasma mass spectrometry (ICP-MS) for the purpose of detecting blood lead levels below 10 μg/dL has not yet been examined. Paired blood samples from 177 children ages 5.2–12.8 years were tested with LCS and ICP-MS. Triplicate repeat tests …

Rwanda's Natural Remedies: A Fresh Look At The Fight Against Malaria, Leandre Nsabimana Ndisanze

Pomona Senior Theses

Malaria remains one of the most devastating parasitic diseases globally, disproportionately affecting sub-Saharan Africa, where Rwanda continues to face high transmission rates and rising resistance to conventional interventions. Despite decades of control efforts, the emergence of drug-resistant Plasmodium falciparum and insecticide-resistant Anopheles mosquitoes threatens to reverse recent gains. This research responds to the urgent need for sustainable and culturally relevant alternatives by exploring the therapeutic potential of Rwandan traditional medicinal plants. These indigenous remedies, long used by local healers, offer an underexplored reservoir of bioactive compounds that may provide the basis for novel antimalarial drugs.

The central hypothesis of this …

Insights Into Factors Influencing Radical Coupling Chemistry Of Monolignols During Lignification And Induced Changes In Plant Secondary Metabolism, Rachel Poornima Sutherland

Theses and Dissertations--Chemistry

Lignin is a complex aromatic biopolymer and an important constituent in plant cell walls. The process of lignin biosynthesis, known as lignification, is poorly understood and challenging to study but has important implications in a variety of fields including sustainable energy, bioengineering, and materials science and is therefore of interest to pursue. In the final stage of lignification, H-, G-, and S-monolignols are oxidized by laccase and peroxidase enzymes to generate radical species that couple to form dimers and further oligomeric species to ultimately produce the lignin polymer. Biomimetic lignin model systems utilize in vitro oxidative coupling reactions as an …

Towards Developing Glut2 Specific Probes For Biochemical And Biomedical Applications, Abdelrahman Ismail

Dissertations, Master's Theses and Master's Reports

Facilitated Glucose transporters (GLUTs) are membrane proteins responsible for the uptake of simple sugars and other structurally similar metabolites in all mammalian cells. One of the hallmarks of cancer is dysfunctional sugar metabolism, known as the Warburg effect, and one of the manifestations of that effect is abnormal GLUT expression. There are 14 known GLUT proteins with different expression patterns in different tissues, and tumors tend to express certain GLUTs that are not present in surrounding healthy tissue. Therefore, selective targeting of GLUTs presents a potentially powerful tool for diagnostics and treatment of cancer and other diseases. This has been …

Characterization Of Aromatic Stationary Phases For Uses In High Performance Liquid Chromatography, Anastasia Davis

Honors Theses

High Performance Liquid Chromatography (HPLC) is an analytical chemist technique used to separate a sample into its components to characterize and study a specific molecule or compound. Traditionally, High-Performance Liquid Chromatography in different industries, such as the environmental and pharmaceutical fields, uses stationary phases that are already well characterized, such as the C18 stationary phase for separation. However, aromatic stationary phases have recently been produced, which have phenyl groups bonded to the interior surface of the column. Still, they have not been well characterized because of how modern they are. This project characterized several aromatic stationary phases (Biphenyl, pentafluorophenyl, and …

Microfiltration Membrane Pore Functionalization With Primary And Quaternary Amines For Pfas Remediation: Capture, Regeneration, And Reuse, Sam Thompson, Angela Gutierrez, Jennifer Bukowski, Dibakar Bhattacharyya

UK CARES Faculty Publications

The widespread production and use of multi-fluorinated carbon-based substances for a variety of purposes has contributed to the contamination of the global water supply in recent decades. Conventional wastewater treatment can reduce contaminants to acceptable levels, but the concen- trated retentate stream is still a burden to the environment. A selective anion-exchange membrane capable of capture and controlled release could further concentrate necessary contaminants, mak- ing their eventual degradation or long-term storage easier. To this end, commercial microfiltration membranes were modified using pore functionalization to incorporate an anion-exchange moiety within the membrane matrix. This functionalization was performed with primary and …

Amperometric Bio-Sensing Of Lactate And Oxygen Concurrently With Local Field Potentials During Status Epilepticus, Eliana Fernandes, Ana Ledo, Greg A. Gerhardt, Rui M. Barbosa

Neurology Faculty Publications

Epilepsy is a prevalent neurological disorder with a complex pathogenesis and unpredictable nature, presenting limited treatment options in >30 % of affected individuals. Neurometabolic abnormalities have been observed in epilepsy patients, suggesting a disruption in the coupling between neural activity and energy metabolism in the brain. In this study, we employed amperometric biosensors based on a modified carbon fiber microelectrode platform to directly and continuously measure lactate and oxygen dynamics in the brain extracellular space. These biosensors demonstrated high sensitivity, selectivity, and rapid response time, enabling in vivo measurements with high temporal and spatial resolution. In vivo recordings in the …

Inhaling The Unseen: Exploring The Presence Of Microplastics In The Human Respiratory Tract, Kara Coffman-Rea

Graduate Research Theses & Dissertations

Microplastics (plastic pieces less than 5 mm) have emerged as a pervasive form of pollution acknowledged as a universal threat to both environmental and human health. Their small size and widespread distribution pose significant risks to marine life, terrestrial ecosystems, and ultimately human health. Microplastics have been reported in food and drink items designated for human consumption, in cosmetics and consumer goods designed for human use, and within the air we breathe, each providing an entry route for microplastics to enter the human body. Recently, microplastic particles have been detected in a variety of human tissue samples (e.g., lung tissue). …