Analytical Chemistry Commons^™

Characterization Of Nanoparticles Using Inductively-Coupled Plasma Mass Spectrometry, Jabez D. Campbell

Graduate Theses/Dissertations

Nanomaterials are a relatively new class of materials that have many applications which span a wide host of fields from medical products to consumer products. The possible compositions and forms of nanomaterials are just as varied as the applications. Therefore, a versatile characterization method is needed for researchers and regulators alike to ensure nanomaterials are properly used. Single Particle Inductively Coupled Plasma Mass Spectrometry (SP-ICP-MS) is a functional method that could fill the characterization need in the nanomaterial research field. Using data from both SP-ICP-MS tests and data from literature established characterization methods, the viability of making SP-ICP-MS the standard …

Development Of A New Spe Uplc–Ms/Ms Method For Extraction And Quantitation Of Toluene Diamine On Gloves Following Toluene Diisocyanate Exposure, Asma Daoud, Pierre-Luc Cloutier, Sébastien Gagné, Livain Breau, Jacques Lesage

Études primaires

Rationale

Toluene diisocyanate (TDI) is a highly reactive isocyanate commonly used as a mixture of 2,4- and 2,6- isomers in the production of flexible foams. Exposure to TDI occurs primarily through vapour inhalation in workplaces where TDI is produced or used, but dermal exposure is also possible during some tasks. To ensure workplace safety, accurate monitoring of TDI and toluene diamine (TDA) levels is required. Methods of quantifying field effectiveness of gloves in preventing dermal exposure have not been established. Therefore, there is a need to develop a new practical method for assessing glove effectiveness for TDI/TDA.

Method

A new …

Effects Of Localized Oxygen Production By Electrolysis On The First-Generation Glucose Sensor Response, Nandita Halder

Graduate Theses and Dissertations

Glucose sensors are very important for detecting blood glucose both in vitro and in vivo. First-generation glucose biosensors were based on the glucose oxidase (GOx) enzyme using molecular oxygen as the electron acceptor and therefore oxygen dependent. Unfortunately for in-vivo work, oxygen in the body is variable and limited. Alternative approaches to overcome the oxygen dependency came with their own limitations. The widely used and commercially available ex-vivo glucose test strip uses a mediator in place of oxygen to free it from oxygen dependency. The mediator-based technology, in most cases cannot be transferred to in vivo applications due to the …

Quantifying Phosphatidylethanol From Blood Samples, James V. Defrancesco, Majid Afshar

Chemistry: Faculty Publications and Other Works

Disclosed herein is a method for quantifying phosphatidylethanol (“ PEth ”), direct ethanol biomarker, from a blood sample using gas chromatography mass spectrometry. The method disclosed herein is useful for diagnosing acute and chronic alcohol abuse.

Advancing The Preclinical Development Of Secondary Metabolites From Cacospongia Mycofijiensis For The Treatment Of Cancer, Joseph Morris

Natural Sciences and Mathematics | Biological Sciences Master's Theses

The marine sponge Cacospongia mycofijiensis from the Indo-Pacific has proven to be a source of structurally diverse secondary metabolites that are biologically active against a variety of distinct targets. Current interest in the secondary metabolites of C. mycofijiensis largely stems from a) their potent and preferential cytotoxicity for cancer cell lines versus normal cells, making many of them promising leads as cancer therapeutics and b) the novel mechanisms of action responsible for their impressive cytotoxicity. However, limited compound availability has resulted in a paucity of studies aimed at advancing the preclinical development of these secondary metabolites from C. mycofijiensis for …

Heavy Metals In Ends Liquids: A Comparative Analysis Of Products From The United States, England, Canada, And Australia, Ashleigh Coggins-Block

Forensic Science Theses

The International Tobacco Control (ITC) Policy Evaluation Project 4-Country Survey, which this thesis is a part of, aims to compare policies and electronic nicotine delivery system (ENDS) products between the United States, England, Canada, and Australia. Since they can pose many serious health risks, this thesis investigated the presence of and source of heavy metals, including lead, nickel, chromium, and cadmium, in ENDS e-liquids. The source of these metals in ENDS e-liquids has been disputed between cultivated tobacco used to derive nicotine and the metal parts of ENDS devices. ENDS purchased in 2017 from each of the four countries of …

Developing A Microdialysis Sampling-Based Biofilm/Macrophage Co-Culture Model, Alda Diaz Perez

Graduate Theses and Dissertations

The host immune system and bacterial cells are known to interact during the human lifetime. Bacteria secrete a wide variety of signaling molecules, known as quorum sensing (QSC) molecules, that modulate the host immune system. While immune-biofilm interactions involve this chemical signaling network, the mechanisms through which this occurs are not well understood. This work aimed to develop a new method that can be used not only in vitro settings but also in vivo. The microdialysis sampling technique has widely been used in in vitro and in vivo settings in humans, mice, and rats for the collection of neuropeptides, cytokines, …

Development Of A Rapid Drug Detection Method For Insects Using Paper Spray Ionization Mass Spectrometry (Psi-Ms), Alexandria Plyler

Undergraduate Research and Scholarship Symposium

Insects have the ability to reflect the chemical environment that they have developed in. Thus, necrogenous insects can reflect the chemical environment of cadavers they have fed on. Forensic scientists can potentially utilize insect larvae as an alternate biological matrix to detect drugs in cadavers that are skeletonized, burned, or otherwise badly damaged. Analysis of insects using paper spray ionization mass spectrometry (PSI-MS), an analytical method requiring little to no sample preparation, could prove a rapid, cost-effective, and non-destructive alternative form of toxicological analysis. Traditional tissue analysis via GC and LC-MS often require lengthy sample preparation, use expensive reagents, and …

Legacy And Emerging Per- And Polyfluoroalkyl Substances : Analysis, Environmental Distribution, And Bioconcentration, Richard Anthony Brase

Legacy Theses & Dissertations (2009 - 2024)

Per- and polyfluoroalkyl substances (PFAS) constitute a broad class of anthropogenic chemicals that have been used in numerous industrial and consumer-product applications since the late 1940s. The environmental persistence of these compounds in combination with their widespread commercial use have led PFAS to be recognized as contaminants of concern on the global scale. Despite regulatory efforts calling for the decreased use of certain perfluorocarboxylic and -sulfonic acids referred to as “legacy” PFAS, these compounds continue to be detected in both environmental and biological matrices. Moreover, manufacturers have begun to replace the legacy PFAS with emerging alternatives for which the regulations …

Harnessing Acoustic Streaming For Bioanalysis In Microfluidics, Xiaojun Li

Graduate Theses, Dissertations, and Problem Reports (ETD)

In the past few decades, microfluidic technology has been developed rapidly in both fabrication methods and multifunctionality integrations, making it a powerful tool for a wider variety of biological applications. The device fabrication method has expanded from conventional polymer-based micro devices to 3D-printed micro devices, and allows multiple functions such as electric, optic, magnetic and acoustic to be integrated on a single platform. This dissertation focuses on method development of acoustic streaming-based microfluidics in bioanalysis such as immunoassay, enzyme kinetics and DNA fragmentation analysis. In this dissertation, a micromixer was developed based on acoustic streaming generated from sharp-edge structure vibration …

Carbon Dots As Artificial Peroxidases For Analytical Applications, Shih-Chun Wei, Yang-Wei Lin, Huan-Tsung Chang

Journal of Food and Drug Analysis

Nanozymes have become attractive in analytical and biomedical fields, mainly because of their low cost, long shelf life, and less environmental sensitivity. Particularly, nanozymes formed from nanomaterials having high surface area and rich active sites are interesting since their activities can be tuned through carefully controlling their size, morphology, and surface properties. This review article focuses on preparation of carbon dots (C dots) possessing peroxidase-like activity and their analytical applications. We highlight the important roles of the oxidation states and surface residues of C dots and their nanocomposites with metal, metal oxides, or metal sulfides playing on determining their specificity …

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 …

Development Of A Method For The Detection And Quantification Of Various Benzodiazepines And Z-Drugs In Human Blood And Qualitative Identification In Urine Samples Using Liquid Chromatography Mass Spectrometry (Lc-Ms/Ms), Haley Michel

Williams Honors College, Honors Research Projects

This method developed in the toxicology department at the Cuyahoga County Medical Examiner’s Office (CCMEO) detects 40 benzodiazepines and metabolites along with several z-drugs in blood and urine by liquid chromatography tandem mass spectrometry. A sample amount of 0.5 mL was used to detect analytes in postmortem drug facilitated sexual assault and impaired driving cases. Twenty-nine analytes met criteria for quantification while the remaining 14 were used as qualitative indicators. Bias and precision results for quality controls met criteria, staying within ±15% except for clonazolam and etizolam which were within ±20%. Quantitative reporting criteria which included dilution integrity was met …

A Validated Uplc-Ms/Ms Method For The Determination Of Aliphatic And Aromatic Isocyanate Exposure In Human Urine, Maggy Lépine, Lekha Sleno, Jacques Lesage, Sébastien Gagné

Études primaires

4,4′-Methylenediphenyldiisocyanate (MDI), toluenediisocyanate (2,4-TDI and 2,6-TDI), and 1,6′-hexamethylenediisocyanate (HDI) are all commonly used in the production of polyurethane-containing materials in different application areas. Workers exposed occupationally to these compounds may develop sensitization with the potential to lead to asthma. Isocyanates are metabolized in vivo by conjugation to macromolecules and/or by acetylation prior to being eliminated in urine. The hydrolysis of urine samples releases free amine compounds from these metabolites as biomarkers of exposure, specific to each parent isocyanate: 4,4′-methylenedianiline (MDA), toluenediamine (2,4-TDA and 2,6-TDA), and hexamethylenediamine (HDA). To address the need for a validated method that could be used for …

Structure Elucidation Of A Pyrrolobenzodiazepine Alkaloid And A Biologically Active Polyketide Produced By Rhodococcus Sp. Mtm3w5.2 Via Two-Dimensional Nmr Spectroscopy, Garrett Johnson

Electronic Theses and Dissertations

As the battle against ever-increasing drug resistence bacteria rages on, novel and sometimes more complex natural products can be used to combat this. In this study, two-dimensional NMR techniques were utilized to collect a complete spectral data set for two natural products. The first structure, a synthesized Pyrrolobenzodiazepine alkaloid natural product was confirmed through these methods. The second, a strain of Rhodococcus, MTM3W5.2, produces a novel antibacterial molecule in broth cultures and the active compound was fractionated using a Sephedex LH-20 column. Chromatographic purification yielded a pure sample at 58.90 minutes, RT.58. HRMS data deduced an exact mass of …

Near Real-Time Determination Of The Prevalence Of Cannabinoids, Cathinones, And Synthetic Opioids, Catherine O'Rourke, Bikram Subedi

Scholars Week

Unregulated new psychoactive substances (NPS) in “pure” or “preparation” forms are designed to mimic the effects of controlled substances, and are introduced and reintroduced in the market as a cheap substitute of established regulated drugs in quick succession to loophole the law enforcement efforts on combating drugs. For example, carfentanil, a synthetic opioid activates the opioid receptors similar to morphine but it is astoundingly potent compared to a typical drug of abuse (100 times more potent than fentanyl and 10,000 times more powerful than morphine). Based on the cost- and time-intensive forensic analysis, National Drug Early Warning System reported the …

Determination Of Cannabinoids, Cathinones, And Synthetic Fentanyls Using Wastewater-Based Epidemiology, Catherine O'Rourke, Bikram Subedi

Posters-at-the-Capitol

Unregulated new psychoactive substances (NPS) in “pure” or “preparation” forms are designed to mimic the effects of controlled substances, and are introduced and reintroduced in the market as a cheap substitute for established regulated drugs in quick succession to loophole the law enforcement efforts on combating drugs. For example, carfentanil, a synthetic opioid activates the opioid receptors similar to morphine but it is astoundingly potent compared to a typical drug of abuse (100 times more potent than fentanyl and 10,000 times more powerful than morphine). Based on the cost- and time-intensive forensic analysis, National Drug Early Warning System reported the …

In Vitro Evaluation Of Ovarian Cancer Tumorigenesis As A Function Of Quinone Oxidoreducatse-1 And Cell Phenotype, Milcah S. Jackson

LSU Doctoral Dissertations

In vitro multicellular spheroids are attractive model systems for assessing genetic and epigenetic changes that occur in diseased tissues. Understanding how such alterations in gene and subsequent protein expression affect disease progression and metastasis, drug resistance, and recurrence is of great interest in cancer research. In this regard, examining expression and activity of proteins, such as those with cytoprotective ability that are overexpressed in cancer cells, in addition to cell phenotype (i.e., stem-like, epithelial, mesenchymal, or mixed), are two ways to evaluate genetic and epigenetic changes. Moreover, determining the impact that cytoprotective proteins and cell phenotype have on tumor formation …

Effect Of Salt Concentration On Electrochemical Detection Of Dna, Ziming Dong, Eddie Madrigal, Ryan West Dr.

Creative Activity and Research Day - CARD

Electrochemical approaches for biological sensing offer the potential advantages of facile sample preparation, fast response times, ease of parallel and multiplexed measurements, and the possibility of miniaturization (of sample sizes, electrodes, and associated electronics). All of these factors contribute towards the feasibility of electrochemical methods in biological sensing and analysis. This potential has already been achieved with the commercialization of blood glucose meters, which often rely on an electrochemical transduction mechanism. We have previously demonstrated the ability to electrochemically detect and differentiate complementary and mismatched DNA using our method of melting DNA duplexes at electrified gold surfaces, i.e. e-melting. Recently, …

Mobilization Of Calcium Across Mineralized Tissues In Yellow Perch, Perca Flavescens, Taylor Bopp

Student Scholar Showcase

Bones in many higher teleost fish, such as percids and centrarchids, lack osteocytes that function as both chemo- and mechano-sensors, and thus, are not actively involved in homeostasis of blood calcium level. Nonetheless, the vertebrae of yellow perch, Perca flavescens (P. flavescens), living in darker and low calcium (Ca) water, have demonstrated adaptive modeling and remodeling of vertebrae to be more mineralized and thus enhance transmission of the axial muscle torque into the thrust force for the C-start predator escape behavior. The prey-predator interaction is expected to occur at closer range between prey fish and predator fish in …

Hour-Level Resolution On Consumption Pattern Of Substance Abuse, Jarrett Mauk, Rhiannon Huffines, Brittney Nelson, Tara Croft, Bikram Subedi

Scholars Week

Conventional survey-based approaches of determining the consumption statistics of drugs in communities are suffered from non-response biases, and typically underestimate the actual consumption. Time and cost-intensive conventional approaches, therefore, can’t be utilized to determine high-resolution temporal variability in drug consumption. In this study, the temporal trend of consumption of 10 illicit and 26 prescribed neuropsychiatric drugs was determined at hour-level resolution utilizing wastewater-based epidemiology. The hourly composite raw wastewater (every 10 minutes) samples were collected for three consecutive days in a typical week (total of 72 samples), analyzed for target drug residues using UPLC-MS/MS, and back-calculated the consumption rate of …

Student-Faculty Collaborative Research Grant Report, 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 …

Multidimensional Mass Spectrometry Of Chemonic™ Ccg-6 Nonionic Surfactant With Separation By Polarity And Shape, Charles Johnson

Williams Honors College, Honors Research Projects

Chemonic™ CCG-6 surfactant is a water-soluble poly(ethylene glycol) (PEG) conjugated alkyl glyceride emollient. This surfactant exists as a complex mixture of a glycerol cores conjugated with poly(ethylene glycol) branches (PEGylation) that were partially esterified with caprylic (C8) and capric (C10) acids. These may be esterified on one, two, or all three arms of the glyceride. The architecture of the structures in this mixture was studied using multidimensional mass spectrometry (MS). Mass spectrometry was interfaced with ultra-performance liquid chromatography (UPLC) and ion mobility (IM) separation. The mixture was separated by reversed-phase LC, oligomers of the star-branched polymer were separated according to …

2nd Tier Assay For The Detection Of Congenital Adrenal Hyperplasia By Virginia’S Newborn Screening Laboratory: Steroid Profile By Hplc-Ms/Ms, Christopher E. Nixon

Theses and Dissertations

Congenital Adrenal Hyperplasia (CAH) encompasses several disorders related to disruptions in the adrenal steroid production pathway. These disruptions may cause virilization of the external female sex organs, incorrect gender assignment, precocious puberty, and in the most severe form, may cause life-threatening salt wasting and adrenal crisis if not detected and treated early in the newborn period.

17α-Hydroxyprogesterone (17-OHP) is the primary target for immunofluorescence detection of CAH from dried blood spots in newborn screening (NBS). Unfortunately, current immunoassay techniques for the detection of CAH suffer from high false positive rates. The primary factors contributing to false positive determinations can include …

Xflow: An Algorithm For Extracting Ion Chromatograms, Mathew M. Gutierrez, Rob Smith

Graduate Student Theses, Dissertations, & Professional Papers

Abstract: Mass spectrometry is a fundamental tool for modern proteomics. The increasing availability of mass spectrometry data paired with the increasing sensitivity and fidelity of the instruments necessitates new and more potent analytical methods. To that end, we have created and present XFlow, a feature detection algorithm for extracting ion chromatograms from MS1 LC-MS data. XFlow is a parameter-free procedurally agnostic feature detection algorithm that utilizes the latent properties of ion chromatograms to resolve them from the surrounding noise present in MS1 data. XFlow is designed to function on either profile or centroided data across different resolutions and instruments. This …

Bayesian Analytical Approaches For Metabolomics : A Novel Method For Molecular Structure-Informed Metabolite Interaction Modeling, A Novel Diagnostic Model For Differentiating Myocardial Infarction Type, And Approaches For Compound Identification Given Mass Spectrometry Data., Patrick J. Trainor

Electronic Theses and Dissertations

Metabolomics, the study of small molecules in biological systems, has enjoyed great success in enabling researchers to examine disease-associated metabolic dysregulation and has been utilized for the discovery biomarkers of disease and phenotypic states. In spite of recent technological advances in the analytical platforms utilized in metabolomics and the proliferation of tools for the analysis of metabolomics data, significant challenges in metabolomics data analyses remain. In this dissertation, we present three of these challenges and Bayesian methodological solutions for each. In the first part we develop a new methodology to serve a basis for making higher order inferences in metabolomics, …

3d-Printed Fluidic Devices And Incorporated Graphite Electrodes For Electrochemical Immunoassay Of Biomarker Proteins, Abdulhameed Alabdulwaheed

Electronic Theses and Dissertations

Biomarkers are measurable indicators of health status or disease state that can be used for diagnosis and may help guide patient treatment strategies. Enzyme-linked immunosorbent assays (ELISA) and other many clinical techniques currently used for measuring biomarker proteins lack sensitivity, demand high analysis cost, are often not well-suited for measuring multiple biomarkers in a single sample, and require long analysis times. Here, we demonstrate simple, low-cost 3D-printed flow-through devices with integrated electrodes modified with gold nanoparticles (AuNPs) for electrochemical immunoassays of S100B, a biomarker protein related to conditions like skin cancer and brain injuries. Flow-through devices are fabricated from photocurable-resin …

Designing A Calibration Set In Spectral Space For Efficient Development Of An Nir Method For Tablet Analysis, Md Anik Alam

Electronic Theses and Dissertations

Designing a calibration set is the first step in developing a spectroscopic calibration method for quantitative analysis of pharmaceutical tablets. This step is critical because successful model development depends on the suitability of the calibration data. For spectroscopic-based methods, traditional concentration based techniques for designing calibration sets are prone to have redundant information while simultaneously lacking necessary information for a successful calibration model. The traditional method also follows the same design approach for different spectroscopic techniques and different formulations, thereby lacks the optimizing capability to be technique and formulation specific.

A method for designing a calibration set in the Near …

Relationships Among Vitamin D Deficiency, Metabolic Syndrome, Smoking Behavior, And Physical Activity, Ethan Pham

Walden Dissertations and Doctoral Studies

Aging increases the risk of both vitamin D deficiency and metabolic syndrome. Vitamin D deficiency and metabolic syndrome may be related, although there are mixed findings. Furthermore, literature suggests other factors such as physical fitness activity and smoking behavior are associated with Vitamin D deficiency and the development of metabolic syndrome. A number of studies have documented associations between Vitamin D levels and physical fitness activities, while other studies found correlations between Vitamin D levels, metabolic syndrome, and smoking behavior. However, no previous study has examined the links between physical fitness activity, smoking behavior, Vitamin D levels, and the risks …

Instrumental Aspects Of Oxygen Sensing: Quantitation And Recalibration Of A Biofouled Oxygen Sensor, Marlena Patrick

Graduate Theses and Dissertations

In vivo oxygen sensing is a critical area of research for medical applications, such as ischemic stroke, but this important topic is not fully understood or resolved. In addition, the best method for calibration of in vivo sensors is as yet undetermined. For all implantable devices, biofouling, the adsorption of biological material to the device surface, is another significant problem with no clear or well-defined solution. One method employed is to apply a protective polymer membrane to the sensor surface in order to minimize the adsorption of biological material. The work described here investigates two polymers applied to a gold …