Analytical Chemistry Commons^™

Refining A Flow Injection Analysis Method For Trace Concentrations Of Iron In Seawater, Brooke I. Stafford, Liam W. Hodgson, Noah S. Schuhmann, Elijah J. Vestal, Claire P. Till

IdeaFest: Interdisciplinary Journal of Creative Works and Research from Cal Poly Humboldt

Iron is an essential micronutrient required for the growth of phytoplankton, the base of the oceanic food chain. Iron exists in the ocean in extremely low concentrations, limiting primary productivity in ~⅓ of the surface ocean, and can be affected by physical processes such as upwelling of water masses, and by biological and chemical processes within the water. In order to further our understanding of iron availability in the ocean, here we refine and improve our understanding of an analytical method to measure nanomolar iron in seawater. The method used is an adaptation of Lohan et al. (2006), a flow …

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 …

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 …

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 …

The Chemical Nature Of Colors, Bryant Corbin, Bryant Corbin

Longwood Senior Thesis Proposal

No abstract provided.

Development Of Fast And Comprehensive Approaches For Gunshot Residue Interpretation Using Ambient Ionization, Mass Spectrometry, And Microparticle Sampling Studies, Thomas Dimmey Ledergerber

Graduate Theses, Dissertations, and Problem Reports (ETD)

The information derived from the forensic examination of gunshot residue (GSR) can be critical during the investigative and trial stages in the criminal justice system. However, the complexity of the GSR deposition, transfer, and persistence mechanisms calls for meticulous handling and identification processes. Novel advances in evidence interpretation and analysis via instrumental methods are current areas of growing interest that must be pushed along the chain from research to practice in a timely manner. Therefore, this research focuses on developing both rapid and comprehensive methods for detecting gunshot residue evidence and effectively communicating its significance to the investigators or trier …

Making And Breaking Bonds: Studying Intrinsic Chemistry In The Gas-Phase, Luke Metzler

Electronic Theses and Dissertations

The nature of chemical interactions can be difficult to ascertain in the condensed phase; chemistry can be observed, but with the plethora of variables such as solvation, mixes of counter-ions, and complex equilibria, the true intrinsic chemical properties of a given chemical species may be obfuscated. By conducting research in the gas-phase, many of these variables can be reduced, if not eliminated entirely, which can allow for the careful observation of the true physical phenomena driving chemical reactivity.

The research presented herein focuses on the use of ion-trapping (specifically in a linear ion trap) as a method for unveiling the …

Turning Trash Into Treasure: Using Old Optical Spectrometers As Learning Tools In Instrumental Analysis, Ken Overway

Chemistry Faculty Scholarship

Chemical instrumentation is complex and expensive. When an instrument becomes nonfunctional, its pedagogical value remains despite its inability to make measurements. This work presents a laboratory experiment which gives new purpose to old optical spectrometers while building knowledge and confidence of students in their understanding of chemical instrumentation. Students are given a guided tour of spectroscopic instruments, starting from the simplest, and are asked to identify components and draw the optical path of each instrument. Allowing students to look inside of decommissioned instruments gives students a chance to see the differences and similarities of optical spectrometers while reinforcing the form …

Solution Combustion Synthesis And Characterization Of Fumarolic Mineral Dolerophanite, Copper (Ii) Oxide Sulfate, Eric J. Cyganowski

Chemistry & Biochemistry Theses - Archive

Dolerophanite Cu₂OSO₄ is a rare mineral found almost exclusively in the fumaroles of volcano systems and is sensitive to temperature and humidity conditions. It has a monoclinic C2/m crystal structure characterized by two-dimensional layers composed of sulfate anions dispersed amongst copper (II) oxide backbones. There has been recent interest in dolerophanite due to the magnetic properties of its Kagome-like lattice as well as its potential use as a photocatalyst or Li-ion battery electrode. Literature on the material however has been limited by the available synthesis strategies. As such, this thesis work presents a novel strategy …

Differentiation Of Human, Dog, And Cat Hair Fibers Using Dart Tofms And Machine Learning, Laura Ahumada, Erin R. Mcclure-Price, Chad Kwong, Edgard O. Espinoza, John Santerre

SMU Data Science Review

Hair is found in over 90% of crime scenes and has long been analyzed as trace evidence. However, recent reviews of traditional hair fiber analysis techniques, primarily morphological examination, have cast doubt on its reliability. To address these concerns, this study employed machine learning algorithms, specifically Linear Discriminant Analysis (LDA) and Random Forest, on Direct Analysis in Real Time time-of-flight mass spectra collected from human, cat, and dog hair samples. The objective was to develop a chemistry- and statistics-based classification method for unbiased taxonomic identification of hair. The results of the study showed that LDA and Random Forest were highly …

Quantitative Analysis Of The Proteomic Selectivity Of Acidic Reductive Alkylation Of Peptides, Connor Jewell

Honors Scholar Theses

Proteome quantification is a complicated process which takes on many methods, usually involving peptide derivatization and complex mass spectral analysis. Scores of techniques have been utilized to address issues of incomplete quantification. The implementation of IPTL labeling, or isobaric peptide terminal labeling, is a recent addition to the literature, which exploits the supposedly selective labeling of N-termini of tryptic peptides from the C-termini of lysine residues due to differences in basicity. This method has been shown to improve quantitation by reducing spectral complexity and provide more accurate and reproducible results on peptide abundance. Investigations into the selectivity of terminal derivatization …

The Concentration Of Heavy Metals In Lincoln Nebraska's Tap Water, Evan Neuhaus

Honors Program: Senior Projects (Public)

Heavy metals are commonplace in nature, and are typically found in scarce quantities in all drinking sources. However, in high enough concentrations, they can have a myriad of negative health effects. This study seeks to find the concentrations of such metals in the Lincoln water supply utilizing the resources of the Water Center at the University of Nebraska at Lincoln. To test for discrete concentrations of trace elements, a method of using Inductively Coupled Plasma Mass Spectrometry (ICP-MS) was implemented. ICP-MS uses plasma to ionize and atomize a sample which is then filtered into a series of cones into a …

Organic Gunshot Residue : Detection, Identification, And Characterization For Forensic Purposes, Shelby R. Khandasammy

Legacy Theses & Dissertations (2009 - 2024)

The major focus of this thesis was to explore methods for the detection, identification, and characterization of organic gunshot residues (OGSRs) for forensic purposes using various spectroscopic techniques. There are four major projects detailed in this thesis. The first project details the development of a novel-two step method for the detection and identification of organic gunshot residues using fluorescence spectroscopy for detection and Raman spectroscopy as a confirmatory step. The second chapter builds upon the study conducted in the first chapter by applying the novel-two step method covered in the first chapter to OGSRs directly fired into cloth substrates. This …

Fast Photochemical Oxidation And Footprinting Of Proteins Via Trifluoromethyl Radical Chemistry, Elaine Morrow

Honors Theses

Fast photochemical oxidation of proteins (FPOP) is a useful tool in proteomics because of the ability for modifications to occur on the scale of microseconds which reduces the modifications to tertiary and quaternary structure allowing for more accurate labeling of the protein. Labels for FPOP are generated from various radicals in our experiments which include hydroxyl radicals and trifluoromethyl radicals. Hydroxyl radicals are easily generated by using an excimer laser (KrF laser, 248 nm) or a UV flash lamp (as a part of the Fox™ System) by the photolysis of hydrogen peroxide. Trifluoromethyl radicals, however, need hydroxyl radicals to be …

Development And Applications Of Touch Chemistry Biometrics Analysis Of Latent Fingermarks By Maldi-Ms, Cameron M. Longo

Legacy Theses & Dissertations (2009 - 2024)

Fingerprint evidence has long been a pillar of forensic science and has been used for over a century as a means of identifying an individual. This is accomplished through the comparison of friction ridge patterns, which are inherently unique to each individual, and the practice of visualizing fingerprints and comparing them has become a well-studied field. While these techniques have been optimized and improved over time, they generally rely only on the physical pattern to provide information about the donor, and not the content of the fingerprint material itself. In the modern era, steps have been made to extract from …

Gas-Phase Acid-Base Properties And Conformations Of Oligopeptides Through Mass Spectrometry And Computational Studies, Yuntao Zhang

University of the Pacific Theses and Dissertations

This dissertation presents a comprehensive study of the peptides of interest to deeper understand the gas-phase acid-base properties in relation to their conformations and chirality. In the first part of the study, two pairs of alanine (A)-based isomeric peptides consisting of a basic probe, lysine (Lys) or 2,3-diaminopropionic acid (Dap), were investigated to understand the nature of the enhanced basicity when the basic probe was moved from the N-terminus to the C-terminus. In the second part of the study, alanine-based peptides containing a cysteine (C) as the acidic probe were investigated to understand the chirality effects on the gas-phase acidity …

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

Chemistry Theses and Dissertations

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

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

Legacy Theses & Dissertations (2009 - 2024)

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

The Detection And Identification Of Blood On Interfering Substrates Using Raman Spectroscopy And Hamand For Forensic Purposes, Jalissa M. Thomas

Legacy Theses & Dissertations (2009 - 2024)

Body fluids, such as blood and semen, can provide invaluable information to a criminal investigation. As such, it is imperative that body fluid evidence is properly detected and identified. Our laboratory has developed a methodology to universally detect and identify body fluids using Raman spectroscopy and chemometrics. This methodology was developed under ideal conditions, which are rare in the field. Body fluid evidence can be found on substrates that produce a large Raman signal that can hinder detection of body fluid traces, which produce a weak signal. This project proposes the use of a statistical program called HAMAND (Hypothetical Addition …

Mass Spectral And Chemometric Analysis For The Detection And Identification Of Forensically Relevant Materials, Meghan Grace Appley

Legacy Theses & Dissertations (2009 - 2024)

Forensic science is the application of science to the law which in and of itself covers a substantial number of disciplines. Many of these involve the detection and identification of materials using analytical techniques. Traditional analysis methods include microscopy, spectroscopy and mass spectrometry. The materials encountered by forensic practitioners are ever evolving, resulting in the need to develop new methods to complement conventional techniques to enhance the evidentiary value of the samples. The research presented here shows that novel methods including direct analysis in real time–high-resolution mass spectrometry (DART-HRMS), thermal desorption coupled with gas chromatography-mass spectrometry (TD-GC-MS), solid-phase microextraction (SPME) …

The Potential For Remote Sensing Measurement Of Dissolved Organic Carbon As A Tool For Metal Risk Assessments, Mickey Nielsen

Theses and Dissertations (Comprehensive)

The biotic ligand model (BLM) is a tool used to quantitatively evaluate how receiving water chemistry affects the bioavailability of metals. Sensitivity testing can be used to understand how the model outputs vary in response to systematic changes in water chemistry inputs. This will allow users of such models to understand how accurate their input parameters must be for a specified level of confidence in the output. Our focus was on dissolved organic carbon (DOC), which is often the most limiting data for application of BLM approaches to metals risk management. To potentially address DOC data limitations remote sensing can …

Electrostatic Denaturation Of Dna-Cisplatin Adducts, Eddie Madrigal

Master's Theses

In this thesis, electrochemical approaches are used to determine the properties of deoxyribonucleic acid (DNA) by electrostatic denaturation. The electrochemical routine involves an application of a destabilization potential, an equilibration potential, and a square wave voltammogram (SWV) to monitor the extent of melting. Our method uses a monolayer consisting of thiol modified DNA and mercaptohexanol on a gold electrode. These electrodes are then incubated in a complementary sequence tagged with methylene blue. By using our electrostatic denaturation technique, different parameters are explored, such as surface densities, surface coverages, and ionic strengths. As proof of concept, these techniques were applied toward …

Visualization Without Vision – How Blind And Visually Impaired Students And Researchers Engage With Molecular Structures, Croix J. Laconsay, Henry B. Wedler, Dean J. Tantillo

Journal of Science Education for Students with Disabilities

This article examines the tools and techniques currently available that enable blind and visually impaired (BVI) individuals to visualize three-dimensional objects used in learning chemistry concepts. How BVI individuals engage with and visualize molecular structure is discussed and recent tactile (or haptic) and auditory methods for visualization of various chemistry concepts are summarized. Remaining challenges for chemistry education researchers are described with the aim of highlighting the potential value of educational research in further enabling BVI students to pursue careers in science, technology, engineering, and mathematics (STEM) fields.

Evaluation Of The Mechanisms And Effectiveness Of Nano-Hydroxides, Wood And Dairy Manure-Derived Biochars To Remove Fluoride And Heavy Metals From Water, Anna Rose Wallace, Wenjie Sun Dr, Chunming Su Dr

Civil and Environmental Engineering Theses and Dissertations

The development of effective treatment processes for the removal contaminants, such as fluoride and heavy metals, from polluted water have been urgently needed due to serious environmental health and safety concerns. In this dissertation, a variety of materials including various (hydro)oxide nanomaterials, biochars and surface modified biochar were studied to evaluate their effectiveness and mechanism on removing fluoride or mixed heavy metals from water.

In the Chapter 2, this study investigated the adsorptive removal of fluoride from water using various (hydro)oxide nanomaterials, focusing on ferrihydrite, hydroxyapatite (HAP) and brucite, which have the potential to be used as sorbents for surface …

Hypervalent Iodine Compounds With Carboxylate And Tetrazolate Ligands, Avichal Vaish

Chemistry Theses and Dissertations

In modern organic chemistry, hypervalent (HV) iodine(III) compounds are frequently used as oxidizing agents but application of λ³-iodanes in polymer and material chemistry is still underexplored. This dissertation describes the preparation of dynamic and self-healing materials by employing ligand exchange reactions involving HV iodine(III) compounds of the type ArIL₂ (Ar = Aryl, L = ligand, e.g., carboxylate or (pseudo)halide). These compounds can undergo ligand exchange reactions in presence of nucleophiles (Nu^-) to form ArINu₂. Diacetoxyiodo benzene was successfully employed as a crosslinker to prepare dynamic and self-healing gels derived from carboxylate-containing polymers. Furthermore, …

Studying Carbon Dioxide Solvent Properties By Microwave Spectroscopic Investigations Of Vinyl Fluoride/Carbon Dioxide Clusters And Developing New Approaches To Decode Rotational Spectra, Prashansa Kannangara

Masters Theses

Supercritical carbon dioxide (sc-C0₂) is an excellent green solvent, but its properties are not thoroughly understood. For example, fluorinated compounds have higher than expected solubility in sc-C0₂. Microwave spectroscopy is one way to learn more about sc-C0₂ because it can be used to determine detailed structures of small clusters of molecules. The purpose of this investigation was to study weak hydrogen bonding interactions in complexes of fluorinated ethylene (solute) with carbon dioxide (C0₂, solvent). Investigations on dimers with one C0₂ molecule and fluorinated ethylene were carried out previously and found two different …

Characterizing Body Fluids With Raman Spectroscopy : Towards Real World Application, Marisia Ann Fikiet

Legacy Theses & Dissertations (2009 - 2024)

This project continues the research on a new method of body fluid identification and furthers its field capabilities. This method of identification uses Raman spectroscopy and advanced chemometrics to distinguish between body fluids. It is an improvement on current methods because it is confirmatory, non-destructive, and has simple sample preparation. The first objective of this research is to create a model for differentiating body fluids for a new desktop instrument. It was determined that due to resolution differences from a research grade instrument, a new model needed to be made for this the desktop instrument. This model will be able …

Roaming Transition States And Highly Accurate Thermochemistry: A Pepico Study Of Two Small Combustion Systems, Kyle John Covert

University of the Pacific Theses and Dissertations

Two small combustion systems, methyl hydroperoxide (CH₃OOH) and 2-propanol ((CH₃)₂CHOH), were studied using imaging photoelectron photoion coincidence spectroscopy (iPEPICO), which combines photoelectron spectroscopy and photoionization mass spectrometry to detect coincident photoelectron-photoion pairs. In the photon energy range of 11.4–14.0 eV, energy selected CH₃OOH⁺ ions dissociate into CH₂OOH⁺, HCO⁺, CH₃⁺, and H₃O⁺ ions. The lowest-energy dissociation channel is the formation of the cation of the smallest “QOOH” radical, CH₂OOH⁺. A statistical rate model fitted to the …

Steric Effects Of Alkyl Ammonium Salts On The Combustion Of Exchanged Smectite Clays, Celeste A. Keith

Electronic Theses and Dissertations

Bomb calorimetry was explored as a new method for determining the cation exchange capacity (CEC) of clays. Smectite clays were modified with several alkyl ammonium salts varying in number of carbons and the spatial orientation of the carbons about the central nitrogen atom. The clays used, standards purchased from the Source Clay Repository, have CECs of 44, 80, 88, and 120 meq/100 g. Theoretically, the combustion energy of the organo-clays should be approximately the same for each salt. Any differences in energy would be due to the different structures of the salts and how they are oriented in the interlamellar …

Removal Of Pb2+ Ions From Consuming Water Using A Fabricated Water Filter For Home Use, Pantaree Sodkhoksoong, Papidchaya Chanpong, Thunyarus Rodsawatchuchoke

The International Student Science Fair 2018

Lead contamination in water is one of the worldwide concerned environmental problems. For example, lead leaking from pipe corrosion and solder has been found contaminated in consuming water in many U.S. areas. The uncontrolled release of effluents containing lead from various industries has also caused lead-contaminated water in Thailand. Exposing to lead-contaminated water can lead to serious symptoms (e.g. fatigue, headaches, abdominal pain, irritability, depression, and seizures) or even death. Therefore, the elimination of lead ions (Pb²⁺) from consuming water or from effluents before releasing into the environment is necessary. The selection of adsorbents and the fabrication of …