Physical Sciences and Mathematics Commons^™

Sustainable Bio-Based Solid Phase Extraction Adsorbent For The Determination Of Various Types Of Organic Compounds, Mustafa Zafer Ozel, James H. Clark, Avtar S. Matharu

Turkish Journal of Chemistry

A sustainable, bio-based, mesoporous material, Starbon A800, was explored for use as an adsorbent in solid phase extraction (SPE). A solution containing seven nitrosamines was first used as a standard to optimise conditions for extraction efficiency with Starbon A800. After optimising conditions, 25 compounds of varying polarity (terpenes, phenolics, pesticides, PAHs, amines, and nitrosamines) were extracted with SPE using either Starbon® A800, C18 or Porous Graphitic Carbon (PGC) as the adsorbent, for comparison purposes. At the same time, 3 different elution solvents (heptane, dichloromethane, and ethanol) were used for each type of adsorbent. Hansen solubility parameters can be used to …

Development Of Vacuum-Assisted Headspace High-Capacity Solid-Phase Microextraction For The Determination Of Semi-Volatile Compounds From Samples At Lower Temperatures, Shannon L. Thomas, Kevin A. Schug, Colton Myers, Jason S. Herrington, Reagan L. Miller, Anush Pabley, Frank W. Foss

Chemistry & Biochemistry Dissertations

Vacuum-assisted headspace solid-phase microextraction (Vac-HS-SPME) is a method used to increase solid-phase microextraction sampling of semi-volatile organic compounds. Three studies were conducted using Vac-HS-SPME via gas chromatography - mass spectrometry (GC-MS) methods for analysis of various sample types. First, a study was performed using Vac- HS-SPME combined with a high-capacity (HC) SPME Arrow to determine the operational fundamentals and workflow necessary to achieve optimal extraction of semi-volatile compounds from a model solid matrix (Ottawa sand). The fundamentals investigated included the seals necessary to create a leak-free sampling vial under vacuum conditions; the magnitude of the vacuum exerted, and the time …

Analysis Of Isotopic Isomers By Gas Chromatography And Molecular Rotational Resonance Spectroscopy And Enantioselective Method Development By Liquid Chromatography, Saba Aslani

Chemistry & Biochemistry Dissertations

This dissertation focuses on developing improved methods and a better understanding of gas and liquid chromatographic separation of isotopic isomers and enantiomers. The second and third chapters of this thesis discuss analytical determination of isotopic isomers using gas chromatography. Deuterated compounds have found applications in many fields. They are used in drug discovery due to increased stability and bioavailability and reduced toxicity of the deuterated drug molecules. Also, deuterated compounds are used to investigate reaction mechanisms and rate determining steps. One of the methods of synthesizing deuterated compounds is starting from lower molecular weight deuterated building blocks. Therefore, analysis and …

The Boozi Device’S Effect On Aroma Compounds In Distilled Spirits, Drew Budner, Lindsey Bell, Katherine Thompson-Witrick

Journal of the South Carolina Academy of Science

The BooZi is a commercially available flavor-modifying device that claims to remove the negative flavor agents (congeners) from a number of different types of distilled spirits and wines. SPME was utilized for the extraction of the volatile and semi-volatile compounds within each sample. The analysis of the compounds found in the samples following exposure to the BooZi device were analyzed using a GC-MS. The most significant changes regarding the aroma profile of the distilled spirits were noticeable following 96 hours of exposure. The BooZi device was shown to be effective in reducing the concentration of a number of compounds, including …

Crude Oil Characterization Using Gas Chromatography, Ion Mobility Spectrometry And Mass Spectrometry, Clement A. Olanrewaju

FIU Electronic Theses and Dissertations

The characterization of crude oils at the compositional level remains challenging due to their high chemical complexity and isomeric diversity. The present work expands the analytical separation space of chemical components in crude oils by coupling gas chromatography (GC), trapped ion mobility spectrometry (TIMS), and mass spectrometry (GC-TIMS-MS and TIMS-FT-ICR MS) for the effective separation and identification of isomeric compounds. The coupling of GC and TIMS-MS platform enhanced the peak capacity and showed complementary isomeric separation. The combination of GC-TIMS-MS and GC-EI-MS technique provided a comprehensive characterization of PAHs and similar compounds from crude oils on the basis of retention …

Using Thermodynamics To Evaluate Stationary Phase Polarity In Gas Chromatography- A New Look, Hetal R. Rana

Seton Hall University Dissertations and Theses (ETDs)

Abstract

Gas chromatography is a separation method in which the components of a sample partition between a gaseous mobile phase (carrier gas) and a solid or liquid stationary phase. The stationary phase is usually a polymer coated or chemically bonded to a solid support on the column wall and its function is to separate different components, based on their relative vapor pressure and their intermolecular interactions with the stationary phase. If the analyte polarity is similar to the stationary phase polarity, then the retention time increases because the intermolecular interactions are stronger and if the polarities are different then the …

Development Of Scent Detection And Categorization Algorithm Using Gas Chromatography And Machine Learning, Alex Driehaus

Mahurin Honors College Capstone Experience/Thesis Projects

There are many looking to connect human senses to quantifiable data. Scents are categorized by their descriptions into scent families. These include citrus, floral, and woody. Similar descriptors designate similar families, while different descriptors correlate with different families. Dravnieks compiled an Atlas of chemical descriptors [1]. Such descriptors are cinnamon, fruity, and cadaverous. By analyzing the applicability of these descriptors, the chemicals will be sorted into their scent families.

Gas chromatography generates sample-specific signals of voltage over time. Chromatograms of known scents will serve as a basis for a convolutional neural network. This algorithm will be trained on these signals …

Determination Of Formaldehyde In Textile Dye And Auxiliary Chemicals With Headspace Gas Chromatography-Flame Ionization Detector, Korel Güneş, Zi̇ya Can, Ayşem Arda

Turkish Journal of Chemistry

Formaldehyde is a chemical used in many different industrial sectors and is classified as a carcinogen as well as causing allergic reactions. Due to the health effects of formaldehyde, which is widely used in textile dyes and auxiliary chemicals, its analysis in this type of matrices becomes important. In this study, in order to meet these requirements, formaldehyde was converted to oxime derivative by derivatization with o-(2,3,4,5,6-Pentafluorobenzyl)hydroxylamine hydrochloride. This derivative was successfully sampled with the headspace technique and analyzed with a gas chromatography-flame ionization detector (GC-FID). For the developed method, derivatization and salt effect parameters were investigated. For the method, …

Development Of Standard Operating Procedure With Modified Method To Quantify Benzene And Other Volatile Organic Compounds In Air Samples Using Gas Chromatography, Heather Hall

Electronic Theses and Dissertations

Stephen F. Austin State University (SFASU) Department of Environmental Science has recently invested in a gas chromatograph which can be used to analyze air samples for volatile organic compounds (VOCs) such as benzene, toluene, ethylbenzene, and xylenes (BTEX). The goal of this project was to develop a standard operating procedure (SOP) and modify the current method for the detection of VOCs associated with oil and gas drilling activity to accommodate the equipment and capabilities of SFASU Environmental Assessment Lab. This study aims to provide the framework for future research in air quality monitoring in the Eagle Ford Shale area. An …

Targeted And Untargeted Chromatography-Mass Spectrometry Methods For Alcoholic Beverage Analysis, Hailee Elizabeth Ratcliffe

Chemistry & Biochemistry Dissertations

There has been an increased interest in the “craft” alcohol industry in recent years. Contrary to larger corporations that focus on standardizing their recipes for mass production, these small, independent businesses can experiment with ingredients and procedures to create unique and flavorful products. Beer and whiskey in particular have seen a surge in popularity, indicating the public may be interested in a deeper understanding of these beverages and their flavors on the chemical level. Brewing and distilling rely heavily on chemistry to perform the proper procedures to obtain the desired product, and to understand the interactions of the various ingredients. …

Linear Discriminant Analysis Based On Gas Chromatographic Measurements For Geographical Prediction Of Usa Medical Domestic Cannabis, Ramia Z. Al Bakain, Yahya S. Al-Degs, James V. Cizdziel, Mahmoud A. Elsohly

Faculty and Student Publications

Fifty four domestically produced cannabis samples obtained from different USA states were quantitatively assayed by GC-FID to detect 22 active components: 15 terpenoids and 7 cannabinoids. The profiles of the selected compounds were used as inputs for samples grouping to their geographical origins and for building a geographical prediction model using Linear Discriminant Analysis. The proposed sample extraction and chromatographic separation was satisfactory to select 22 active ingredients with a wide analytical range between 5.0 and 1,000 μg/mL. Analysis of GC-profiles by Principle Component Analysis retained three significant variables for grouping job (Δ9-THC, CBN, and CBC) and the modest discrimination …

The Evaluation Of Environmental Contaminants Using Static Headspace Gas Chromatography Mass Spectrometry, Vacuum Ultraviolet Detection, Emmanuel Varona -Torres

Chemistry & Biochemistry Dissertations

In analytical chemistry the term “headspace” refers to the vapor that forms above a sample (liquid or solid) in a closed container. Headspace (HS) sampling is the method to promote partition between volatile components from the sample matrix and then analyzed by gas chromatography (GC). HS is an excellent technique to introduce a “clean” vapor sample into the GC and avoids introduction of non-volatile components from the sample matrix and often used for determination of volatile organic compounds (VOCs) with minimal or no additional sample preparation. Concerns about the environmental impact of fossil fuel extraction techniques (i.e., hydraulic fracturing and …

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 Dmap-Catalyzed Acylation Of Alcohol -- A Mechanistic Study, Tania Veronica Alvarez Castro

Theses and Dissertations

The mechanistic studies of Acylation of Alcohols catalyzed by 4-(N,N- Dimethyl-amino)-pyridine (DMAP) has been heavily studied in the literature. This reaction has attracted considerable interest from the synthetic and mechanistic points of view in recent years. In this research, the acylation of alcohols is prepared from cyclohexanol and acetic anhydride that is catalyzed by DMAP using triethyl amine (NEt3) as the auxiliary base and dichloromethane (DCM) as solvent. The reaction and final product will be analyzed by using gas chromatography (GC) and reaction progress kinetic analysis (RPKA). The mechanistic insights obtained in the present study should be useful for understanding …

Novel Integrated Nano-Sensors For Analysis Of Chemical Compounds In Natural Gas Applications, Taylor Robinson

Mahurin Honors College Capstone Experience/Thesis Projects

Semiconductor sensors have been important environmental gas detectors since the 1990s, and are commonly used to detect hydrogen, oxygen, alcohol vapor, and even harmful gases such as carbon monoxide. A gas chromatography approach is a well-proven and compact separation technique to identify and quantify multiple compounds in a complex background such as a true natural gas environment. Real time field monitoring implementing classical GC and standard sensors (FID, PID, etc.) have a lot of limitations due to its bulky size, heavy weight, and high maintenance. In this study, we developed a portable instrument through the utilization of novel solid-state sensors …

Performance Of Nitrogen As A Carrier Gas In Capillary Gas Chromatography Using A Thin Film Column, Brittany A. Handzo

Seton Hall University Dissertations and Theses (ETDs)

Gas chromatography (GC) is one of the most widely used analytical techniques for the separation and analysis of volatile compounds. Solids, liquids, and gases, organic and inorganic materials, and large molecular weight compounds can all be analyzed via this technique. Gas chromatographic separations are fast, accurate, and reliable. One of the reasons why these separations are so efficient is because of the carrier gas. The purpose of the carrier gas is to carry the injected sample through the column. It is known as the mobile phase and does not interact chemically with the sample. Common carrier gases include helium, hydrogen, …

Development Of A New Analytical Method For Separation And Quantitative Determination Of Synthetic Cathinones In Urine Using Gas Chromatography Tandem Mass Spectrometry, Jasim Ali Mohamed Alzaabi

Chemistry Theses

This thesis is concerned with a new class of drugs known as synthetic cathinones, which overruns the drug markets in recent years as “legal highs” drugs, under different commercial names such as bath salts. All synthetic cathinone derivatives consist of a chiral center and usually sold out as a racemic mixture. Usually, one of the two enantiomers will have stronger central nervous system (CNS) stimulatory activity and the other one may have no significant CNS activity or addictive properties. A new sensitive and selective analytical method was developed for the simultaneous determination of ten synthetic cathinones enantiomers in spiked urine …

Non-Target Analyses Of Novel Psychoactive Substances; Inherent Variation In Gcms Relative Abundances And Gas Phase Hydrogen Deuterium Exchange Isomer Discrimination, Kristin Michelle Kelly

Graduate Theses, Dissertations, and Problem Reports

Novel psychoactive substances (NPSs) are synthetically derived compounds designed to mimic the effects of other illicit drugs. An endless cycle of NPSs continually reach the drug market due to limitations in drug legislation creating two problems: (1) non-availability of standards and (2) multiple isobars indistinguishable even to high resolution mass spectrometry. Gas chromatography-mass spectrometry (GCMS) is the most common instrument used for compound identification in non-targeted seized drug analysis. Compound identification using this technique relies on mass spectra where the percent relative abundances (%RAs) of all m/z values are compared manually or searched against a library database. Lacking standards, laboratories …

Designing Thermally Stable Ionic Liquid Stationary Phases For Gas Chromatography And Examining Their Structure-Property Relationships, Rahul A. Patil

Chemistry & Biochemistry Dissertations

Ionic liquids are popular in diverse scientific applications because of their unique physicochemical properties. The physicochemical properties of ionic liquids can be “tuned” by the modification of their structural moieties. Understanding of structure-property relationship is important if one wants to introduce a desired property in ionic liquid for a specific application. The initial part of this thesis will discuss the understanding of structure-property relationship of dicationic ionic liquids. Ionic liquids with high thermal stability are useful in many applications from simple solvents for high temperature reactions to high vacuum lubricants for space applications. This thesis presents the design, synthesis, and …

New Methods For Discovery, Fingerprinting, And Analysis Of Cannabis Sativa Natural Products, Allegra Leghissa

Chemistry & Biochemistry Dissertations

Cannabis sativa is an herbaceous annual that has always been of great interest due to its uses in the manufacturing of textiles and cordage, as well as for its medicinal properties. The two main bioactive components of C. sativa are cannabinoids and terpenes; the former confer the medicinal and pharmaceutical benefits, as well as the psycho-activity, to the plant, while the latter are largely responsible for aroma and flavor. Because of the importance of both sets of analytes, it is crucial to have a comprehensive understanding and characterization of these compounds, and different methods have been developed to address these …

Stable Bromine Isotope Signature Of Bromoform From Enzymatic And Abiotic Formation Pathways And Its Application In Identifying Sources Of Environmental Bromoform In The Damariscotta River, Chengyang Wang

Honors Theses

Bromoform is a major source of atmospheric bromine. Most bromoform is produced by marine organisms including macroalgae and phytoplankton, using the enzyme bromoperoxidase (BPO). Bromoform can also be a byproduct of industrial processes such as water disinfection. Identifying sources of environmental bromoform is still a challenge. A novel technique of using quadrupole mass spectrometry coupled to a gas chromatography (GCqMS) was developed and optimized for Br isotope analyses. The study shows that GCqMS in single ion monitoring (SIM) mode can measure 81Br with precision of around ±0.7‰ (60pmol bromoform injected). This study aims to investigate stable Br isotopes of bromoform …

Derivatization Of Small Acids To Enhance Sensitivity In Gas Chromatography Mass Spectrometry And Gas Chromatography Vacuum Ultraviolet Spectroscopy, Chih-Hao Wang

Chemistry & Biochemistry Theses

Disinfection by-products (DBPs) are a significant concern in drinking water quality. Haloacetic acids, which are generated from disinfection processes, are one of the major groups in disinfection by-products. Because they induce potential harmful effects for human health, the US government has already established regulations to control the levels of haloacetic acids in drinking water. In order to control the presence of haloacetic acids in drinking water and monitor other potential harmful compounds, an appropriate analytical method is needed. In this study, a gas chromatography (GC) method was developed for detecting haloacetic acids in water. Three different derivatization reagents were compared …

Advances In Separation Methodologies: Fatty Acid, Fatty Amine, Water, And Ethanol Determination By Ionic Liquid Gas Chromatography And D-Amino Acid Evaluation In Mammalian Brain By Liquid Chromatography, Choyce Asher Weatherly

Chemistry & Biochemistry Dissertations

This dissertation focuses on two chromatographic techniques, gas chromatography (GC) and high performance liquid chromatography (HPLC). The goal of the GC work is to describe advances in separation methodologies focusing on the separation and quantitation of commercially related compounds (i.e. fatty acids, fatty amines, water, and ethanol). Four ionic liquid (IL) columns were evaluated for rapid analysis and improved resolution of long-chain methyl and ethyl esters of omega-3, omega-6, and additional positional isomeric and stereoisomeric blends of fatty acids found in fish oil, flaxseed oil, and potentially more complicated compositions. The potential for improved resolution of fatty acid esters is …

Method Development For Qualification And Quantification Of Cannabinoids And Terpenes In Extracts By Gas Chromatography-Mass Spectrometry, Allegra Leghissa

Chemistry & Biochemistry Theses

Cannabinoids are a class of chemical compounds that act on cannabinoid receptors in cells. These receptors have different kinds of ligands, including endocannabinoids (produced in the body by humans and animals), phytocannabinoids (found mainly in Cannabis sativa), and synthetic cannabinoids. At least 85 different phytocannabinoids have been isolated; different cannabinoids are believed to have different effects and possible benefits in medical treatments, and it is therefore fundamental to classify cultivars prior to their medical use. The other class of compounds that characterize C.sativa are terpenes. They confer flavor and fragrance that are unique to each plant and further confer botanical …

Application Of An Ionic Liquid Column To The Analysis Of Flavor And Fragrance Ingredients, Nicole L. Curto

Seton Hall University Dissertations and Theses (ETDs)

Traditional, polar (polyethylene glycol/wax) stationary phase gas chromatography columns pose challenges for flavor and fragrance analysis particularly in regards to thermal instability at high temperatures, degradation when exposed to water, unchanging selectivity, and relatively short shelf lives. Recently, capillary columns using ionic liquids as stationary phases have become available. Ionic liquid columns offer a potential combination of high polarity and high temperature stability with unique selectivity. An in depth discussion about the history and development of column phase characterization, with specific emphasis on selectivity and polarity, will allow for a critical look at the polarity scale currently employed to characterize …

Determination Of Multiple Pesticides Residues In Imported Tea In Uae Using Liquid And Gas Chromatography And Tandem Mass Spectrometry, Sarra Ali Mohammed Hassan Almulla

Theses

An accurate, rapid and reliable method for the simultaneous determination of 48 pesticide residues in United Arab Emirates imported tea (Green and Black) by liquid and gas chromatography coupled with tandem mass spectrometry LC–ESI (+) - MS/MS and GC-EI-MS/MS. Multiple reaction monitoring (MRM) mode was used in which two transitions for each compound for pesticide identification and quantification in the presence of internal standards. Modified quick, easy, cheap, effective, rugged, safe (QuEChERS) method was used for sample clean up and preparation for chromatographic analysis. The performance of the newly developed analytical method was validated in accordance with EU SANCO guidelines …

Environmental Applications Of Chromatography-Mass Spectrometry, Wisam Abdulabbas Flayyih Al Isawi

Masters Theses

Gas chromatography-mass spectrometry (GC-MS) and liquid chromatographymass spectrometry (LC-MS) are powerful analytical techniques that combine the separation power in a stationary phase with the detection power of mass spectrometry. GCMS and LC-MS have gained dominant positions in identifying and quantifying different analyte species due to their high selectivity, high sensitivity, and high reproducibility.

My research utilizes the analytical power of LC-MS and GC-MS to address two environmental issues: 1) Identification of biodegradation products of the ionic liquid 1- butyl-3-methylimidazolium chloride (BMIMCl) by an activated sludge microbial community using LC-MS and 2) identification and quantification of polycyclic aromatic hydrocarbons (PAHs) in …

High Flow Air Sampler For Rapid Analysis Of Volatile And Semi-Volatile Organic Compounds, Xiaofeng Xie

Theses and Dissertations

Volatile and semi-volatile organic compounds are ubiquitous, and some of them are hazardous. The ability to rapidly detect and identify trace levels of them in air has become increasingly important. The conventional device used today for sampling and concentrating them in air is thermal desorption tubes filled with specific sorbents, which can only collect air samples at flow rates of 100-200 mL/min. In order to detect low concentration (ppt level) VOC compounds, long sampling time (>2 h) and sensitive detection are required. At the same time, portable instrumentation for on-site analysis has been developing rapidly. The somewhat lower performance …

Analysis Of Synthetic Cannabinoids By Direct Analysis In Real Time Quadrupole Time-Of-Flight Mass Spectrometry And Gas Chromatography Quadrupole Time-Of-Flight Mass Spectrometry, Tyler S. Torbet

FIU Electronic Theses and Dissertations

The aim of this study was to investigate the utility of direct analysis in real time quadrupole time-of-flight mass spectrometry and gas chromatography quadrupole time-of-flight mass spectrometry in the analysis of 162 different synthetic cannabinoids. Direct analysis in real time quadrupole time-of-flight mass spectrometry is shown to be a rapid and accurate analytical method for synthetic cannabinoids. Spectra can be generated with less than 1.5 ng of the drug in under a minute and be successfully searched against previously generated ESI-QTOF libraries in most cases (118/130 drugs tested) as well as can also be applied to the identification of synthetic …

Revisiting The Biodesulfurization Capability Of Hyperthermophilic Archaeon Sulfolobus Solfataricus P2 Revealed Dbt Consumption By The Organism In An Oil/Water Two-Phase Liquid System At High Temperatures, Gökhan Gün, Yuda Yürüm, Gi̇zem Di̇nler Doğanay

Turkish Journal of Chemistry

The ability of the hyperthermophilic archaeon Sulfolobus solfataricus P2 to grow on organic and inorganic sulfur sources was investigated. A sulfur-free mineral medium was employed with different sources of carbon. The results showed that inorganic sulfur sources display growth curve patterns significantly different from the curves obtained with organic sulfur sources. Solfataricus has the ability to utilize DBT and its derivatives, but it lacks BT utilization. Solfataricus} utilizes DBT at a rate of 1.23 \mu mol 2-HBP h^{-1} g DCW^{-1} even at 78 °C, at which DBT is known to be unstable. After enabling DBT stabilization using a two-phase culture …