Analytical Chemistry Commons^™

Photochemistry Of Polycyclic Aromatic Hydrocarbons With Environmentally Relevant Metals, John P. Haynes

Electronic Theses and Dissertations

The details of the work presented in this dissertation focus on simulated reactions in the atmosphere and water systems between persistent aromatic compounds and varying species of metals with an emphasis on iron. Bulk water suspensions of a standard soil and polycyclic aromatic hydrocarbons (PAH) were analyzed for soluble iron by inductively-coupled plasma mass spectroscopy (ICP-MS) following a 16 hour reaction period using simulated sunlight. Significant increases in soluble iron were only seen with 2-3 ring linear PAH and carboxylic acids.

A two-stage study was conducted to investigate the potential for and possible mechanisms involving the photo-oxidation of PAH into …

Environmental Forensics Study Of Crude Oil And Petroleum Product Spills In Coastal And Oilfield Settings: Combined Insights From Conventional Gc-Ms, Thermodesorption-Gc-Ms And Pyrolysis-Gc-Ms, Michael A. Kruge, José Luis Gallego, Azucena Lara-Gonzalo, Noemi Esquinas

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

A representative set of five oil spill samples from four different regions displayed different product characteristics and different levels of weathering. Three of them were taken along shorelines affected by marine oil spill events, viz., Aboño and Prestige (Spain) and Deepwater Horizon (USA) and the other two were taken at inland oil spill sites (Angola and Kuwait). A multi-faceted environmental forensics approach revealed key molecular features. In addition to the conventional GC/MS analysis of saturated and aromatic fractions, the polar fractions also were analyzed, revealing a complex series of linear alkanones in those oil samples particularly enriched in aliphatics. Thermodesorption-GC-MS …

Determination Of The Oxidative Capacity Of Soot Toward Gsh And Characterization Of Soot Physicochemical Properties, Kaylee Troth

All Master's Theses

Fine atmospheric particulate matter (PM_2.5) emitted during the combustion of fossil and biomass fuels is known to adversely affect human health. While the underlying mechanisms are thought to be driven by the generation of reactive oxygen species (ROS), specific particle characteristics responsible for this detrimental effect are not well understood. In this research, the quantitative determination of the biologically relevant antioxidant, glutathione (GSH), was optimized for use as an indicator of oxidative stress to shed light on relevant particle characteristics. This was accomplished via fluorescent spectroscopy for GSH determination by way of reaction with o-phthalaldehyde (OPA), a …

The Study Of The Degradation Of Hexabromocyclododecane In A Heterogeneous System Containing Fe(Ii) Adsorbed To The Iron Oxide Hematite., Kristian K. Roopnarine

Dissertations and Theses

The reaction of hexabromocyclododecane (HBCDD), a widely used brominated flame retardant, was studied in a heterogenous mixture containing reactive Fe(II) adsorbed to the iron oxide hematite. The adsorbed Fe(II)/iron oxide system has shown to be a potent reductant in the transformation of organic contaminants with relatively water soluble organic contaminants. There currently aren’t many studies involving hydrophobic organic contaminants, such as HBCDD, in this reducing Fe(II)/iron oxide system. The results indicate that across the pHs 6.86, 6.95, 7.15 and 7.35 γ and β-HBCDD are degraded within a couple days. The pseudo-first order rate constants at pH 6.95 are 0.049 hr …

The Development Of A Simplified Alkalinity Titration Analyzer, Reba Van Beusekom

Graduate Student Theses, Dissertations, & Professional Papers

Alkalinity is the acid neutralizing capacity for water, meaning alkalinity measures how sensitive an aquatic system is to acidic inputs. Currently, there are various measuring systems for alkalinity available including chemical test kits, potentiometric techniques, and colorimetric methods. Commercially available products lack the ease of use combined with precision and accuracy desired for on-line process and environmental monitoring. The goal of this project is to develop a simplified alkalinity titration analyzer, called the easyTMT, to measure alkalinity with precision and accuracy comparable to the best conventional methods. The system, under development, uses the Tracer Monitored Titration (TMT) technique. TMT …

Aqueous Photochemistry Of 2-Oxocarboxylic Acids, Alexis Eugene

Theses and Dissertations--Chemistry

Atmospheric aerosols affect climate change by altering the energy balance of the atmosphere, and public health due to their variable chemical composition, size, and shape. While the formation of secondary organic aerosol (SOA) from gas phase precursors is relatively well understood, it does not account for the abundance of SOA observed during field measurements. Recently it has become apparent that in-aerosol aqueous chemical reactions likely provide some of the missing sources of SOA production, and many studies of aqueous phase processes are underway.

This work explores the fates of the simplest 2-oxocarboxylic acids, glyoxylic acid (GA) and pyruvic acid (PA), …

Evaluation Of Autonomously Measured Alkalinity, Ph, And Pco2 Variability On A Coral Reef, Brittany Peterson

Graduate Student Theses, Dissertations, & Professional Papers

Currently, our understanding of alkalinity (A_T) variability in highly dynamic environments such as coral reefs is limited by the dearth of A_T measurements. In order to better characterize these environments, high temporal resolution A_T data are needed. This work employed the newly developed Submersible Autonomous Moored Instrument for Alkalinity (SAMI-alk), a fully autonomous in situ A_T analyzer, to study seawater A_T variability. The main goals of this research were to evaluate the utility of combining the SAMI-alk data with currently available in situ measurements of pH and partial pressure of carbon dioxide (p …

Testing The Underlying Chemical Principles Of The Biotic Ligand Model (Blm) To Marine Copper Systems: Measuring Copper Speciation Using Fluorescence Quenching, Tara N. Tait, James C. Mcgeer, Scott Smith

Chemistry Faculty Publications

Speciation of copper in marine systems strongly influences the ability of copper to cause toxicity. Natural organic matter (NOM) contains many binding sites which provides a protective effect on copper toxicity. The purpose of this study was to characterize copper binding with NOM using fluorescence quenching techniques. Fluorescence quenching of NOM with copper was performed on nine sea water samples. The resulting stability con- stants and binding capacities were consistent with literature values of marine NOM, show- ing strong binding with log K values from 7.64 to 10.2 and binding capacities ranging from 15 to 3110 nmole mg C ^{−1 …}

Multivariate Statistical Analyses Of Air Pollutants And Meteorology In Chicago During Summers 2010–2012, Katrina Binaku, Martina Schmeling

Chemistry: Faculty Publications and Other Works

Aerosol, trace gas, and meteorological data were collected in Chicago, Illinois during 2010–2012 summer air studies. Ozone, nitrogen oxides, acetate, formate, chloride, nitrate, sulfate, and oxalate concentrations as well as temperature, wind speed, wind direction, and humidity data were explored by both principal component analysis (PCA) and canonical correlation analysis (CCA). Multivariate statistical techniques were applied to uncover existing relationships between meteorology and air pollutant concentrations and also reduce data dimensions.

In PCA, principal components (PC) revealed a relationship of ozone and nitrate concentrations with respect to temperature and humidity, coupled with transport of species from the south in relation …

Unmanned Aerial Systems For Monitoring Trace Tropospheric Gases, Travis J. Schuyler, Marcelo I. Guzman

Chemistry Faculty Publications

The emission of greenhouse gases (GHGs) has changed the composition of the atmosphere during the Anthropocene. Accurately documenting the sources and magnitude of GHGs emission is an important undertaking for discriminating the contributions of different processes to radiative forcing. Currently there is no mobile platform that is able to quantify trace gases at altitudes(UASs) can be deployed on-site in minutes and can support the payloads necessary to quantify trace gases. Therefore, current efforts combine the use of UASs available on the civilian market with inexpensively designed analytical systems for monitoring atmospheric trace gases. In this context, this perspective introduces the …

Geochemical Fractionation, Speciation, And Bioavailability Of Heavy Metals In Stream Sediments In Aurora, Mo, Miles Pearson

Graduate Theses/Dissertations

Stream sediments from Chat Creek in Aurora, MO, part of the former Tristate Mining District, were digested via a sequential extraction procedure modeled after the Tessier method. Prior sampling had shown elevated levels of zinc, lead, and cadmium in sediments located near former chat piles. Metals in sediments were divided into four geochemical fractions: 1) easily exchangeable, 2) carbonate-bound, 3) iron-manganese oxides-bound, and 4) organic matter-bound. The distribution of the metals within these fractions can help predict the bioavailability and speciation of said metals. The majority of metals were contained in the third and to a lesser extent the fourth …

Evaluation Of A Filtration Sorbent For Remediation Of Arsenic In Groundwater, Clement Do

Electronic Theses, Projects, and Dissertations

A commercially available product, PURA PhosLock, was identified and evaluated for use as a sorbent to remove dissolved arsenic (As) from drinking water. Although marketed as a product to remove phosphate in aquaria, it is composed of iron oxide hydroxide (i.e., FeO(OH)), which is also known to adsorb dissolved As species from water. Arsenic was measured using standard methods and Graphite Furnace Atomic Absorption Spectroscopy. A first rough filtration test was performed to see if the PhosLock adsorbed As well. About 50 g of PhosLock was used to filter 10 L of tap water containing 100 ppb As. No detectable …

Phosphomolybdic Acid Catalysis Of Cellulose Hydrolysis, Troy R. Dolmetsch

Undergraduate Honors Theses

Renewable sources such as cellulose derived biofuels are sought after in order to replace fossil fuel sources that are currently used to meet energy demands. Cellulose is a biological polymer composed of a chain of glucose molecules. Hydrolysis of cellulosic materials then has potential to serve as a source of renewable energy in the form of biofuels. The crystalline structure of cellulose is very stable, and current methods of catalyzed hydrolysis are inefficient for industrial application. This project explores the use of phosphomolybdic acid (PMA) in water to catalyze hydrolysis of microcrystalline cellulose. Temperature of hydrolysis was varied from 40 …

Homogeneous Ligand-Centered Hydrogen Evolution And Hydrogen Oxidation : Exploiting Redox Non-Innocence To Drive Catalysis., Andrew Z. Haddad

Electronic Theses and Dissertations

Hydrogen is a promising carbon-free fuel / energy carrier and is an essential building block for many industrial and agricultural processes. Rising energy demands have ignited interest in the development of carbon-free and carbon neutral energy sources. In this context, hydrogen is an attractive candidate—being energy-dense, carbon-free—and easily accessible through a two-electron reduction of water. Accordingly, many electrochemical homogeneous catalyst systems have been studied, with a focus on understanding the mechanism of hydrogen evolution proceeding through metal-hydride intermediates. However, there has been a renaissance in hydrogen evolution reaction (HER) catalyst design, with many groups implicating ligand redox non-innocence as a …

Functionalized Silica Gel For Adsorption Of Cesium From Solution, Kenneth Marshall Seaton Iii

Electronic Theses and Dissertations

Mesoporous silica gel containing embedded phosphotungstic acid (PTA) was synthesized by sol-gel co-condensation of tetraethyl orthosilicate with PTA in acidic media. The obtained material had high Brunauer-Emmett-Teller Theory (BET) surface area and pore volume. A characteristic band of the Keggin structure of PTA was present in its FT-IR spectrum while its X-ray diffraction patterns were absent. This proved the embedding of PTA on a sub-molecular level and not as a second phase. Acidic sites were determined by neutralization with base in aprotic solvent, followed by titration of the remaining base with an acid. The material demonstrated high adsorption capacity of …

Oxidation Of Substituted Catechols At The Air-Water Interface: Production Of Carboxylic Acids, Quinones, And Polyphenols, Elizabeth A. Pillar, Marcelo I. Guzman

Chemistry Faculty Publications

Anthropogenic activities contribute benzene, toluene, and anisole to the environment, which in the atmosphere are converted into the respective phenols, cresols, and methoxyphenols by fast gas-phase reaction with hydroxyl radicals (HO(•)). Further processing of the latter species by HO(•) decreases their vapor pressure as a second hydroxyl group is incorporated to accelerate their oxidative aging at interfaces and in aqueous particles. This work shows how catechol, pyrogallol, 3-methylcatechol, 4-methylcatechol, and 3-methoxycatechol (all proxies for oxygenated aromatics derived from benzene, toluene, and anisole) react at the air-water interface with increasing O3(g) during τc ≈ 1 μs contact time and contrasts their …

Spectrofluorometric Analysis Of Bisphenol-A In Drinking Water Bottles, Jeff Brochetti

Student Scholar Showcase

Spectrofluorometric Analysis of Bisphenol-A in Drinking Water Bottles

Bisphenol-A (BPA) is of environmental concern due to its ability to act as an endocrine disruptor in humans and many other animals. In the food industry, BPA is widely used in the production of plastic bottles and plastic liners in aluminum cans. Over time, trace amounts of BPA can leach from the container and into the contents inside. A new method of testing for trace amount of BPA involved the formation of an inclusion complex with ß-Cyclodextrin. With the formation of the inclusion complex, it becomes much easier to analyze low concentrations …

Reactivity Of Ketyl And Acetyl Radicals From Direct Solar Actinic Photolysis Of Aqueous Pyruvic Acid, Alexis J. Eugene, Marcelo I. Guzman

Chemistry Faculty Publications

The variable composition of secondary organic aerosols (SOA) contributes to the large uncertainty for predicting radiative forcing. A better understanding of the reaction mechanisms leading to aerosol formation such as for the photochemical reaction of aqueous pyruvic acid (PA) at λ ≥ 305 nm can contribute to constrain these uncertainties. Herein, the photochemistry of aqueous PA (5-300 mM) continuously sparged with air is re-examined in the laboratory under comparable irradiance at 38° N at noon on a summer day. Several analytical methods are employed to monitor the time series of the reaction, including (1) the derivatization of carbonyl (C═O) functional …

Assessment Of Four Solvents For Extraction And Analysis Of The Chemical Composition Of Sansevieria Extrafoliar Nectar Drops By Gas Chromatography-Mass Spectrometry, Hope L. Juntunen, Patrick Videau, Donna Hazelwood, Michael Gaylor

Research & Publications

In the latter part of the 20th century, much effort was devoted to elucidating the chemical constituents of floral and extrafloral nectar secretions, with the primary aim of understanding their ecological roles, especially in regards to attracting pollinators. But, nearly all these studies focused on determining sugar and amino acid constituents. Only a few studies have reported more comprehensive assessments of the organic chemical constituents of plants, with none of those reporting such efforts for Sansevieria taxa (common houseplants known to purify air by bioaccumulating pollutants). To address this knowledge gap, we evaluated the efficacy of four organic solvents with …

Phthalate And Non-Phthalate Plasticizers In Indoor Dust From Childcare Facilities, Salons, And Homes Across The Usa, Bikram Subedi, Kenneth D. Sullivan, Birendra Dhungana

Faculty & Staff Research and Creative Activity

The quality of indoor environment has received considerable attention owing to the declining outdoor human activities and the associated public health issues. The prolonged exposure of children in childcare facilities or the occupational exposure of adults to indoor environmental triggers can be a culprit of the pathophysiology of several commonly observed idiopathic syndromes. In this study, concentrations of potentially toxic plasticizers (phthalates as well as non-phthalates) were investigated in 28 dust samples collected from three different indoor environments across the USA. The mean concentrations of non-phthalate plasticizers [acetyl tri-n-butyl citrate (ATBC), di-(2-ethylhexyl) adipate (DEHA), and diisobutyl adipate (DIBA)] were found …

Mass Loading And Removal Of Pharmaceuticals And Personal Care Products Including Psychoactives, Antihypertensives, And Antibiotics In Two Sewage Treatment Plants In Southern India, Bikram Subedi, Keshava Balakrishna, Derrick Ian Joshua, Kurunthachalam Kannan

Faculty & Staff Research and Creative Activity

Environmental contamination by pharmaceuticals and personal care products (PPCPs) is barely studied in India despite being one of the largest global producers and consumers of pharmaceuticals. In this study, 29 pharmaceuticals and six metabolites were determined in sewage treatment plants (STPs) in Udupi (STP_U: population served ~150,000) and Mangalore (STP_M: population served ~450,000); the measured mean concentrations ranged from 12 to 61,000 ng/L and 5.0 to 31,000 ng/L, respectively. Atorvastatin (the most prescribed antihypercholesterolemic in India), mefenamic acid, and paraxanthine were found for the first time in wastewater in India at the mean concentrations of 395 …

Assessment Of Surface Water Contamination From Coalbed Methane Fracturing-Derived Volatile Contaminants In Sullivan County, Indiana, Usa, Nicholas Meszaros, Bikram Subedi, Tristan Stamets, Naima Shifa

Faculty & Staff Research and Creative Activity

There is a growing concern over the contamination of surface water and the associated environmental and public health consequences from the recent proliferation in hydraulic fracturing in the USA. Petroleum hydrocarbon-derived contaminants of concern [benzene, toluene, ethylbenzene, and xylene (BTEX)] and various dissolved cations and anions were spatially determined in surface waters around 14 coalbed methane fracking wells in Sullivan County, IN, USA. At least one BTEX was detected in 69% of sampling sites (n=13) and 23% of sampling sites were found to be contaminated with all of the BTEX. Toluene was the most common BTEX compound detected across all …

A Novel Method For Determination Of Ammonium Isotope Ratios With Electrospray Ionization Mass Spectrometry, Rebecca J. Chmiel

Honors Theses

Nitrogen (¹⁵N) isotope tracer studies are an invaluable tool for understanding the rate of N transformations in the environment. A mechanistic understanding of N cycling is critical to management of excess N availability in freshwater and marine ecosystems. Conventional methods for measuring ¹⁵N:¹⁴N of dissolved inorganic nitrogen species are time consuming and require large sample volumes. Here, we present a technique for measuring ¹⁵N:¹⁴N in ammonium (NH₄⁺) using electrospray ionization mass spectrometry (ESI-MS). NH₄⁺ present in small volumes of sample (3 ml) is complexed with phenol via …

Choline Chloride Eutectics: Low Temperature Applications, Kaila M. Kuehn, Camille M. Massmann, Natalie R. Sovell

The Journal of Undergraduate Research

Deep eutectic solvents (DESs) have a lower melting point than each of their individual components due to ion dipole interactions or hydrogen bonding. Traditionally, DES are used for processing metals through plating and have many synthesis applications. DES are able to be substituted for hazardous solvents that are traditionally used for metal plating and synthesis. This, along with many other advantageous properties, appear promising for the use of DESs as solvents or for use in electrochemical systems, particularly at low temperatures. Choline chloride:propylene glycol was a novel DES synthesized and analyzed for its properties, including melting point, viscosity, conductivity, heat …

Caffeine Used As A Tracer Of Wastewater Contamination In South Florida, Stephanie Spence

Honors Program Theses

In this study, a method was developed to analyze caffeine levels of water samples collected in Miami, Florida. The method was used to determine caffeine concentrations in reclaimed water samples and environmental water samples using on-line solid phase extraction (SPE) high pressure liquid chromatography (HPLC) high resolution mass spectrometry (HRMS). The rising use and disposal of pharmaceuticals and personal care products are becoming a concern as contaminants increasingly enter lakes, streams, and rivers without proper removal by traditional wastewater treatment processes. Caffeine may be used as a chemical tracer to indicate the presence of contamination in water samples and to …

Mechanisms Of Heterogeneous Oxidations At Model Aerosol Interfaces By Ozone And Hydroxyl Radicals, Elizabeth A. Pillar-Little

Theses and Dissertations--Chemistry

Atmospheric aerosols play an important role in climate by scattering and absorbing radiation and by serving as cloud condensation nuclei. An aerosol’s optical or nucleation properties are driven by its chemical composition. Chemical aging of aerosols by atmospheric oxidants, such as ozone, alters the physiochemical properties of aerosol to become more hygroscopic, light absorbing, and viscous during transport. However the mechanism of these transformations is poorly understood. While ozone is a protective and beneficial atmospheric gas in the stratosphere, it is a potent greenhouse gas in the troposphere that traps heat near the Earth’s surface. It also impacts human heath …

Heterogeneous Base Metal Catalyzed Oxidative Depolymerization Of Lignin And Lignin Model Compounds, John Adam Jennings

Theses and Dissertations--Chemistry

With the dwindling availability of petroleum, focus has shifted to renewable energy sources such as lignocellulosic biomass. Lignocellulosic biomass is composed of three main constituents, lignin, cellulose and hemicellulose. Due to the low value of cellulosic ethanol, utilization of the lignin component is necessary for the realization of an economically sustainable biorefinery model. Once depolymerized, lignin has the potential to replace petroleum-derived molecules used as bulk and specialty aromatic chemicals. Numerous lignin depolymerization strategies focus on cleavage of β-aryl ether linkages, usually at high temperatures and under reductive conditions.

Alternatively, selective benzylic oxidation strategies have recently been explored for …

Drinking Water Disinfection By-Products Detection, Formation And The Precursors Removal Study, Runmiao Xue

Doctoral Dissertations

"Haloacetic acids (HAAs) and trihalomethanes (THMs) are two groups of commonly found disinfection by-products (DBPs). Iodinated THMs and HAAs were observed after disinfection of water containing high level of iodide and are proved to be more toxic than their corresponding chlorinated and brominated species. In the presented dissertation, a novel rapid and sensitive high performance ion chromatography-tandem mass spectrometry (HPIC-MS/MS) method has been developed for simultaneous analysis of all these HAAs, bromate, bromide, iodide, and iodate, seventeen compounds in total, without any tedious sample preparation. Besides an efficient analytical method for the detection of DBPs, seeking for a green disinfectant …

Bioavailable Iron In Equatorial Pacific Ocean Aerosol Samples, Hsiang T Teng

All Master's Theses

Oceanic iron (Fe) fertilization experiments performed in remote regions have established that Fe additions draw carbon into the ocean, at least over the months-long time frame of the experiments. However, the mechanisms that control Fe speciation in atmospheric aerosol particles before and after deposition into the surface ocean remain largely unknown. This is in part due to the analytical challenge of quantifying Fe at environmentally significant sub-nano molar levels. The flow injection analysis method combined with the luminol chemiluminescence analytical system allows us to explore the near-real time determination of pico-molar levels of both Fe(II) and H₂O_{2 …}

Natural Organic Matter Characterization And Lead Speciation As Indicators Of Potential Lead Bioavailability In Aquatic Environments, Giselle Cimprich

Theses and Dissertations (Comprehensive)

Trace metals and natural organic matter (NOM) are ubiquitous in aquatic environments. Some trace metals are essential for aquatic life, while other non-essential metals (like lead) can be toxic if present in great enough concentrations. Natural waters contain a combination of inorganic, and organic ligands capable of binding metals. While the chemistry of inorganic Pb species is well understood, and National Institute of Standards and Technology (NIST) certified K values are readily available, the interactions between metals and organic matter is not so clearly defined. It is important to understand how NOM interacts with metals in the environment, as the …