Analytical Chemistry Commons^™

Purification Of Protoporphyrin Ix Using The Fplc, Ken Overway, Laura Narby

Honors Projects

Protoporphyrin IX (PPIX) is the main pigment in brown eggshells, and it is embedded in the shell gland of hens during the final stages of the egg-making process. This natural dye can be used as a substitute for organic sensitizers in dye-sensitized solar cells (DSSCs). One benefit of PPIX is that it is a natural resource and has a high absorption coefficient in the visible and near-infrared region (NIR). Purified PPIX is extremely helpful in dye-sensitized solar cells because it improves electron injection efficiency, can be chemically modified to improve its absorption efficiency, and can be mixed with nanomaterials such …

Photochemistry At The Air-Aerosol Interface, Yi Rao

Funded Research Records

No abstract provided.

Addressing Knowledge And Data Gaps That Limit Pesticide Risk Assessment For Managed Solitary Bees Used For Alfalfa Pollination, Kimberly J. Hageman

Funded Research Records

No abstract provided.

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 Extraction And Chemical Characterization Of The Avian Pigments Turacin And Turacoverdin, Sarah R. Bekkali

Honors Scholar Theses

Bird coloration is a trait that extends beyond mere aesthetics as it has an extensive range of biological significance. Plumage patterns and hues can influence camouflage, mate choice, social dominance, and physiological performance. Bird fitness, their ability to survive and reproduce, is greatly dependent on color. Melanins, carotenoids, and pterins are well-studied pigment systems that are commonly found across many avian species’. Alternatively, porphyrin-based pigments are rare and less-studied as they only found in turacos a sub-Saharan African bird belonging to the family Musophagidae. This thesis focuses on two pigments of interest: turacin, the deep crimson-red pigment found in …

Tissue-Specific Heavy Metal Accumulation And Sediment–Mangrove Dynamics In Port Everglades, Florida, Dimitrios Giarikos, Amy Hirons, Jason Gershman, Sophie Welch

SECLER Data

Coastal wetlands near industrialized waterways face increasing heavy metal contamination, yet the role of mangroves as biogeochemical buffers remains poorly understood. This study quantified 16 heavy metals in sediments and red mangrove (Rhizophora mangle) tissues (roots, branches, and leaves) across four sites near Port Everglades, Florida, examining tissue-specific partitioning, contamination patterns, and sediment-to-plant transfer. The South Turning Basin (STB) was the principal contamination hotspot, with geometric mean (GM) concentrations of arsenic (As; 27.8 µg/g) and zinc (Zn; 203 µg/g) exceeding threshold effect levels, while Cu exceeded its probable effect level (PEL; 193 µg/g). Mercury (Hg) exceeded its PEL …

Chemometric Analysis Of Dissolved Organic Matter Using Fluorescence, Dani Fellner, Ken Overway

Honors Projects

Univariate spectroscopic techniques have been utilized to measure dissolved organic matter (DOM), but challenges arise in the separation and characterization due to similarities in chemical structures and spectral overlap. Multivariate techniques utilize a combination of known analytes with their unique excitation and emission spectra from fluorescence measurements to quantify amount of each analyte present in the mixture using parallel factor analysis. Tryptophan, tyrosine, and phenylalanine are common amino acids found in environmental samples and can be quantified due to their intrinsic fluorescence qualities. These amino acids can be utilized to estimate the amount of DOM in a sample since proteins …

Limit Of Detection Variations In Polyphenol Mixtures Using Parafac-Feem Spectroscopy, Ken Overway, Brockton Zorn

Honors Projects

Polyphenols are chemical compounds commonly found in food products like olive oil and red wine. Research suggests that their presence in such foods conveys positive cardiovascular and cognitive health benefits. This group of compounds is often difficult to quantify in such samples due to an overlap in the chemical signals and the presence of interferences, such as coloring, found naturally in the food. Use of 3D Fluorescence Excitation Emission Matrix (EEM) measurements combined with pH sensitivity could establish a method in which polyphenols are identified more easily in mixtures. Binary and ternary mixtures of polyphenols were analyzed without the additional …

Multiplexing Reductive Alkylation Of Peptides For Quantitative Proteomics, Kevin C. Souza

Honors Scholar Theses

Reductive alkylation is a robust and commonly used labeling technique for quantifying proteins and peptides in complex samples using mass spectrometry. This technique involves the attachment of alkyl groups to an amino group at the N-terminus and lysine residues of a peptide, causing a mass shift that is detectable using mass spectrometry. This work aims to explore the application of reductive alkyl labeling in multiplexed quantitative proteomics. The first part of the study investigates the effectiveness of the labeling of peptides using a variety of aldehydes via reductive alkylation. The aldehydes were chosen, such that they provided various degrees of …

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 …

Peruvian Pinniped Teeth Trace Element Data-Tracking Ecosystem Variabilites Through Trace Element Record Found In Peruvian Pinniped Dentin, Dimitrios Giarikos, Amy Hirons, Ally E. Sheehan, Radleigh Santos

SECLER Data

The South American sea lion (Otaria byronia; SASL) and the Peruvian fur seal (Arctocephalus australis; PFS) are apex predators within the Humboldt Current ecosystem, where population dynamics respond to both natural variability and anthropogenic pressures, including El Niño–Southern Oscillation (ENSO) events and coastal mining. This study quantified 18 trace elements (TEs) in canine dentin from both species collected at Punta San Juan, Peru using laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) to evaluate long-term environmental exposure. Because dentin is deposited incrementally, it preserves a chronological chemical archive reflecting ontogenetic shifts in diet and habitat use. Overall, TE concentrations were broadly similar …

Comparison Of Analytical Techniques From The Extraction Of Bioactive Compounds From Kratom, Curry, Ginger, And Turmeric, Riley Bruno

Honors Program: Senior Projects (Public)

Plants, herbs, and spices have been used as medicines for thousands of years. Early civilizations often attributed healing properties of plants to magical or divine forces. However, as chemistry and analytical technology advanced between the 16th and 18th centuries, scientists began to understand that bioactive compounds within the plants actually caused these effects. Today, natural products remain extremely important in drug discovery. As the number of newly developed synthetic drugs declines, there has been renewed interest in identifying biologically active molecules from plants. Bioactive molecules are a group of diverse chemical compounds that stimulate a response in living tissues. The …

An Undergraduate Chemistry Experiment Integrating Theoretical And Practical Aspects Of Hypervalent Iodine(I) Compounds, Vladimir L. Kolesnichenko, Galina Z. Goloverda

Faculty and Staff Publications

A simple reaction sequence has been developed to produce iodine chloride-pyridine (PyICl) and pyridinium dichloroiodate (PyHICl2), convenient iodinating agents, in a high yield. Our approach is safe and simple to handle, avoiding the use of elemental chlorine or hazardous manipulations. Designed for an upper-level undergraduate hybrid lecture/lab chemistry course, the experiment integrates key concepts from both inorganic and organic chemistry. The pre-experiment lecture explains the connections between molecular structure, reactivity trends, and reaction types. Over three 4 h lab sessions, students carry out a sequence of quantitative transformations and characterize each intermediate and the final product using ESI mass spectrometry, …

Application Of Organic Geochemistry To The Characterization Of Hydrochar And Biochar: Insights Into Composition And Optimization, Michael A. Kruge, Teresa A. Centeno, Alvaro Amado-Fierro, José Manuel González-Lafuente, Rubén Forján, José Luis Gallego

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

Hydrothermal carbonization has garnered significant attention in recent studies due to potential applications of the hydrochar produced, which overlap with those of torrefied biochar, including soil improvement, carbon sequestration, and energy production. However, unlike the relatively uniform properties of biochar, hydrochar characteristics can vary greatly depending on the feedstock used. Advanced characterization techniques are essential to better understand these materials and enhance their practical applications. Research on hydrochar requires a multi-faceted approach, including molecular-level studies, to optimize production processes and identify specific applications.

In this regard, analytical methods commonly used in organic geochemistry could play a crucial role in deepening …

Photoflow Synthesis And Characterization Of Cis- And Trans-N-Isohumulone, Gregory M. Giovine, Bradley Gallow, Trevor Smith, Bruce Hamper

Undergraduate Research Symposium

Previously published efforts by the Hamper group demonstrated the viability of photochemistry in the isomerization of n-humulone to n-isohumulone. Photochemical isomerization reactions of n-humulone performed under 400nm light over 8 hours resulted in high yields (84% reported) of largely trans-n-isohumulone (>95%). These promising results invited further examination of the photochemical process and the application of photoflow procedure. Herein we report the beginnings of a comprehensive slate of n-humulone isomerization reactions performed under iterative photoflow conditions.

Day-Night Shifts In Water-Soluble Ions Of Size-Resolved Aerosols Before And After The Covid-19 Lockdown In A Coastal Megacity: Metro Manila, Philippines, Grace Betito, Paola Angela Bañaga, Rachel A. Braun, Maria Obiminda Cambaliza, Melliza Templonuevo Cruz, Alexander B. Macdonald, James Bernard Simpas, Connor Stahl, Armin Sooroshian

SOSE Affiliate: Manila Observatory

The COVID-19 pandemic-driven lockdowns offer a unique opportunity to examine how reductions in anthropogenic emissions impacted atmospheric aerosol composition in urban environments. This study investigates the day-night variability of size-resolved water-soluble ions in ambient particulate matter (PM) collected in Metro Manila before (November 2019–February 2020) and after (November 2020–February 2021) lockdown implementation. Using tandem Micro-Orifice Uniform Deposit Impactors (MOUDIs), aerosol samples were collected during daytime (06:00–18:00) and nighttime (18:00–06:00) periods and analyzed for key ionic species (sulfate, ammonium, nitrate, oxalate, sodium, chloride, calcium, and magnesium) via ion chromatography. Submicrometer water-soluble mass declined post-lockdown, particularly during daytime, reflecting suppressed secondary formation …

Simulating Chemiluminescence Spectra Of Oh Radical Using Quantum Dynamical Simulations, Triet M. Cao

Research from the Berry Summer Thesis Institute, 2025

Chemiluminescence is a phenomenon of light emission that occurs when molecules transition from an excited state to the ground state. This phenomenon is widely utilized in applications ranging from quantifying product yields in chemical reactions to biological imaging and atmospheric chemistry studies. It has also been used in many crucial applications in the scarce conditions of heat and electricity, such as light sources for astronomy discovery or deep-sea diving. A notable example of such reactions is combustion, where highly reactive hydroxyl radicals (OH) are products. These radicals exhibit a chemiluminescence spectrum because of the interaction between their ground state and …

Visceral, Neural, And Immunotoxicity Of Per- And Polyfluoroalkyl Substances: A Mini Review, Pietro Martano, Samira Mahdi, Tong Zhou, Yasmin Barazandegan, Rebecca Iha, Hannah Do, Joel Burken, Paul Ki-Souk Nam, Qingbo Yang, Ruipu Mu

Chemistry Faculty Research & Creative Works

Per- and polyfluoroalkyl substances (PFASs) have gained significant attention due to their widespread distribution in the environment and potential adverse health effects. While ingestion, especially through contaminated drinking water, is considered the primary route of human exposure, recent research suggests that other pathways, such as inhalation and dermal absorption, also play a significant role. This review provides a concise overview of the toxicological impacts of both legacy and emerging PFASs, such as GenX and perfluoro butane sulfonic acid (PFBS), with a particular focus on their effects on the liver, kidneys, and immune and nervous systems, based on findings from recent …

Highly Contaminated Sediments From The Gowanus Canal (New York) Superfund Site: An Environmental Forensic Approach, Michael A. Kruge, Kevin K. Olsen, Eric A Stern, Maria Mastalerz, Albert Permanyer

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

The 2.5 km long Gowanus Canal (Brooklyn, NY, USA) is a severely contaminated urban waterway dating from the mid-19th century, listed as a US Environmental Protection Agency (USEPA) Superfund site since 2010. Applying an environmental forensics approach to the extensive USEPA data set, we detect systematic variations in parent PAH ring number distributions in the canal sediments, as well as an extraordinary enrichment in organic carbon. We subjected a supplemental sample set to a more detailed analysis by quantitative pyrolysis-GC-MS, Rock-Eval pyrolysis, and organic petrology. With these sensitive methods, we can confirm the alkyl-PAH fingerprint of coal tar (a legacy …

Signal And Noise Analysis In An Undergraduate Instrumental Analysis Laboratory, Ken Overway

Chemistry Faculty Scholarship

Understanding the difference between signal and noise in a measurement is fundamental to analytical chemists. The typical instruments found in an undergraduate chemistry department can be used to teach this concept, as well as signal averaging, by giving students hands-on experience with measurements and data processing. This work presents an undergraduate laboratory module (homework and experiment) that provides specific instructions for using gas chromatographs, fluorometers, a nuclear magnetic resonance spectrometer, an atomic absorption spectrophotometer, and an infrared spectrometer to collect replicate measurements and a framework for calculating the noise level, baseline, signal level, signal-to-noise ratio (SNR), and the signal thresholds …

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 …

Application Of Analytical Methodologies To The Analysis Of Food Flavoring Agents: Part Ii, James Daniel, Kexin Li, Anaaya Monroe, Melissa C. Rhoten

Spring Showcase for Research and Creative Inquiry

No abstract provided.

Application Of Analytical Methodologies To The Analysis Of Food Flavoring Agents: Part Iii, Samantha Ruano, Bryant Corbin, Moorea Whitfield, Melissa C. Rhoten

Spring Showcase for Research and Creative Inquiry

No abstract provided.

Application Of Analytical Methodologies To The Analysis Of Food Flavoring Agents: Part Iv, Tyler Witt, Anna Wallace, Melissa C. Rhoten

Spring Showcase for Research and Creative Inquiry

No abstract provided.

Per- And Polyfluoroalkyl Substance (Pfas) Degradation In Water And Soil Using Cold Atmospheric Plasma (Cap): A Review, Victor Somtochukwu Mbanugo, Boluwatife Stephen Ojo, Ta Chun Lin, Yue-Wern Huang, Marek Locmelis, Daoru Han

Biological Sciences Faculty Research & Creative Works

Per- and polyfluoroalkyl substances (PFASs) are persistent organic chemicals found in numerous industrial applications and everyday products. The excessive amounts of PFASs in water and soil, together with their link to severe health issues, have prompted substantial public concerns, making their removal from the environment a necessity. Existing degradation techniques are frequently lacking due to their low efficiency, cost-effectiveness, and potential for secondary contamination. Cold Atmospheric Plasma (CAP) technology has emerged as a promising alternative, utilizing energized reactive species to break down PFASs under ambient conditions. Therefore, this review examines the efficacy and effectiveness of CAP in degrading PFASs by …

Facile Synthesis Of Tetraaryl Phosphonium Ionic Liquids, Stephanie C. Jones, Devin J. Schwaibold, Grant Meadows, Brennan Shuler, Richard E. Sykora, Frank Rolf Fronczék, James H. Davis, Benjamin Wicker

EKU Faculty and Staff Scholarship

The syntheses of triphenyl-2-pyridylphosphonium salts, [Mopyphos]A, where A-= BF4-, B(C6H5)4-, (CF3SO2)2N-, Sac-, and Ace-. (Sac-= saccharinate, Ace-= acesulfamate) are described. These salts can be synthesized on a multi-gram scale with good yields and have been characterized by NMR, single crystal XRD, and HRMS. Thermal analyses indicate that the bistriflimide (Tf2N-= (CF3SO2)2N-) salts are especially amenable towards high-temperature ionic liquid (IL) applications with decomposition temperatures above 450 degrees C. The synthetic methods described herein can be utilized to generate several phosphonium bistriflimide ILs of the general formula [(C6H5)3P-Ar]Tf2N, where Ar = N-heteroaryl).

Salmon As An Ecological Pathway Of Contaminants Into Alaskan Food Webs, Miranda Brohman, Gretchen Roffler, Dimitri G. Giarikos, David Kerstetter, Amy C. Hirons

SECLER Data

Salmon are important fish taxa for humans and animals in hemiboreal and subarctic ecosystems. Trace elements and their marine food web bioaccumulation raises biomagnification and potential human health risk concerns. Sixteen trace element concentrations and their health risk assessments were determined in seven different tissues of two Southeast Alaska salmon species (chum, Oncorhynchus keta and pink, Oncorhynchus gorbuscha). Chum tissues had overall higher trace element concentrations compared to pink, which may be attributed to a difference of diets, generally longer-lived and spending more time in the open ocean. All kidney and liver samples exceeded the tolerable daily intake for …

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 …

Refining Chlorosulfonation Methods For The Synthesis Of A Perfluoroalkyl Arylsulfonimide (Pfsi) Monomer, Ainsley P. Foster, Ben Varney, Hua Mei

SPARK Symposium Presentations

Proton-exchange membrane (PEM) fuel cells are sources of energy that are clean, quiet, and highly responsive to changes in power needs, making them promising for use in automobiles and other portable power devices. The electrolyte of a PEM cell–the layer responsible for conductivity–is a polymer membrane, commonly consisting of perfluoroalkyl sulfonic acid (PFSA) polymers. In place of the PFSA polymers, perfluoroalkyl arylsulfonimide (PFSI) polymers are expected to improve the efficiency of PEM fuel cells with better stability and proton conductivity. The trifluovinylether (TFVE) aryl perfluorosulfonamide monomer is a new PFSI monomer proposed to fulfill these benefits once polymerized. The previous …

In Memoriam - Nora Sabelli: Master Orchestrator Of Grant Programs And Mentor For Advancing The Interdisciplinary Learning Sciences Field, Eric Hamilton, Jeremy Roschelle, Roy Pea, Barbara Means, Louis Gomez, Kim Gomez, Nancy Butler Songer

Education Division Scholarship

On Friday, September 6, 2024, the learning sciences field lost a giant in Dr. Nora Sabelli, 87 years old, a personal mentor to many researchers and an inspiration to so many learning scientists and STEM leaders. Nora’s first professional career was as a computational chemist, and later she became a passionate leader in research for improving STEM education. Nora’s time as a senior program officer at the National Science Foundation’s (NSF) Education and Human Resources (EHR) directorate was legendary; she was a force of nature who reshaped funding priorities for stronger science and a stronger connection of science to education …