Analytical Chemistry Commons^™

Determination Of Triglycidyl Isocyanurate From Air Samples By Ultra-Performance Liquid Chromatography Coupled With Coordination Ion Spray Mass Spectrometry, Sébastien Gagné, Marielle Carrier, Simon Aubin

Études primaires

Rationale

Ultra-performance liquid chromatography (UPLC) coupled with coordination ion spray tandem mass spectrometry was used for the analysis of air samples containing triglycidyl isocyanurate. The method is not affected by any chromatographic interference and the filter extract is compatible with the UPLC system, as opposed to approaches using high-performance liquid chromatography coupled with ultraviolet detection and gas chromatography coupled with mass spectrometry.

Methods

Accu-cap^™ filters that had sampled triglycidyl isocyanurate were extracted using a mixture of acetonitrile/acetone (95/5) diluted with 3 volumes of water and were then analyzed. The mass spectrometry method uses sodium as the alkali adduct complexing …

Derivatization And Separation Of Natural Estrogens (Estrone, 17Β-Estradiol, And Estriol) Using Gas Chromatography With Flame Ionization Detection (Gc-Fid), Dena L. Guptill

Masters Theses

A major cause of concern for estrogens found in the environment is that even at very low concentrations (10-100 ng/L) they can have a negative effect on aquatic ecosystems by disrupting endocrine systems. Due to the increasing importance of monitoring the levels of estrogens in the environment, a detection method was developed to identify and quantify three natural estrogens (estrone, 17β-estradiol and estriol) using gas chromatography with flame ionization detection (GC-FID). In addition, the efficacy of two derivatizing agents, N,O-bis(trimethylsilyl) acetamide (BSTA) and N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA), was evaluated. The GC detector (FID) was most responsive with E3, followed by E1 and …

Analytical Method Development For The Detection And Analysis Of Protein Carbonyls, Chelsea M. Coffey

Theses and Dissertations

Oxidative stress can result in changes to many biomolecules and also affect their activities. We are interested in protein carbonylation, a type of unnatural oxidation which has been associated with numerous degenerative disease states and is also a consequence of the natural aging process. Protein carbonyls are stable species, but countless analytical barriers exist in terms of their identification. Thus, the main goal of this work was to develop and optimize analytical methods that could be used to help us better understand which, where, and how proteins are being carbonylated.

Initial studies involved method validation for carbonylating, tagging, and enriching …

Structure-Activity Relationships For The Water-Gas Shift Reaction Over Supported Metal Catalysts, Kaiwalya D. Sabnis

Open Access Dissertations

The Water-Gas Shift (WGS) reaction (CO + H₂O → CO₂ + H₂) is an important chemical process for industrial hydrogen production. The overall goal of this project is to use kinetic experiments and in situ characterization techniques in tandem, in order to derive structure-activity relationships for various catalytic systems. These relationships facilitate the rational catalyst design by identification of catalyst descriptors. In order to establish such relationships, various studies were undertaken, such as (i) effect of transition admetals on the WGS catalysis by molybdenum carbide (ii) effect of residual oxygen content on the performance of …

Strong Field Ionization Of Radicals And Reaction Intermediates, Fadia Cudry

Wayne State University Dissertations

This work presents results of adapting SFI probe for detection of radicals and their isomers. Radicals and reaction intermediates were produced using an established method flash pyrolysis. This combination allows for new insight in studying radicals and provide complementary results to the other detection methods used. This is the first study reporting the use of SFI to detect radicals. This detection will also provide structural information of the radicals under study.

For acetone and isoprene, a detailed study shows the SFI flash pyrolysis mass spectra. These mass spectra were then compared to the spectra produced by other detection techniques. We …

Structure And Stability Of Amyloid Fibrils Studied By Advanced Vibrational Spectroscopy, Marudachalam Shanmugasundaram

Legacy Theses & Dissertations (2009 - 2024)

Protein misfolding often leads to the formation of refractory protein aggregates like amyloid fibrils. These fibrils possess a highly ordered structure and are implicated in over 25 severe diseases including Alzheimer’s, Parkinson’s and prion diseases. This work was focused on understanding the morphology and conformation of amyloid fibrils and their stability after formation. The deconstruction of fibrils as well as other aggregates like inclusion bodies under mild conditions was also investigated using Archaeal chaperones.

Mass Spectrometry-Based Rnomics : Global Surveys Of Ribonucleotide Modifications As Possible Indicators Of Cell Identity, Epigenetic, Metabolic And Pathological State, Rebecca Erin Rose

Legacy Theses & Dissertations (2009 - 2024)

Discovery of the regulatory roles of non-protein coding RNAs (ncRNAs), once considered “junk” or “transcriptional noise”, has prompted a reassessment of the significance of the multifaceted activities of RNA in cellular response, which can result in cell transformation and diseased states. This reassessment, however, can only be accomplished if techniques are developed to capture, characterize and quantify the more than 100 covalent post-transcriptional modifications (PTMs) that adorn natural RNAs. Undoubtedly, the creation of high-throughput platforms such as next-generation sequencing and RNA-seq have provided unparalleled accuracy and sensitivity, however, they rely on strand amplification procedures that are blind to the known …

An Investigation Of Alkaline Earth And Rare Earth Elements In Human Bone Following Long-Term Parenteral Nutrition, Aubrey L. Galusha

Legacy Theses & Dissertations (2009 - 2024)

This investigation focused on a unique collection of archived human bones obtained post-mortem from 7 patients, who had received long-term parenteral nutrition (PN) for up to 21 years. Parenterals are administered intravenously as a nutritional supplement, and may be contaminated with metals, which are completely absorbed into the blood compartment. Some metal contaminants may be deposited in the body’s reservoir for inorganic elements – bone.

Characterization Of Metallic And Semimetallic Oxide Nanoparticles In Industrial Wastewater And Associated Toxicity, Gary Roth

Legacy Theses & Dissertations (2009 - 2024)

Engineered nanomaterials (ENMs) play an increasing role in manufacturing and consumer products. Currently, there is no standard approach to studying ENM toxicity, and a growing body of literature suggests that ENMs may have toxicity differing from similar compounds in bulk or dissolved form. I examined ENMs used in the semiconductor manufacturing process called chemical-mechanical planarization (CMP) for their properties, removal in the wastewater treatment system (WWT), in-vitro toxicity, and location post-inhalation in-vivo. It was found that ENMs in CMP slurries have morphology determined by their elemental composition, but assessment of size and concentration can differ substantially between accepted techniques. Particles …

Advanced Raman Spectroscopic Methods For Structural Characterization Of Amyloid Fibrils And Bionanotubes, Valentin Sereda

Legacy Theses & Dissertations (2009 - 2024)

Amyloid aggregation is a specific form of protein misfolding and self-assembly related to several degenerative pathologies like Alzheimer's and Parkinson's diseases, type-II diabetes, etc. This association with deadly diseases has made amyloid fibrils the focus of intensive research for many decades. Most recently, a significant interest to protein fibrils was also due to the application of the remarkable self-assembling capabilities to form well-structured nano-biomaterials. Self-assembly of short peptide sequences into well-organized structures is another important strategy for bottom-up fabrications of nano-biomaterials. One of the most commonly used building blocks is diphenylalanine, a short dipeptide that has been identified as playing …

Effective Tuning Of Bimetallic Composition Of Gold-Copper Nanomolecules And The Emergence Of Plasmon-Like Feature In Optical Spectra, Asantha Champika Dharmaratne

Electronic Theses and Dissertations

Au144-xCux(SR)60 alloy nanomolecules were synthesized and characterized by using ESI-MS to atomic precision. A maximum of 23 copper atoms replace the gold atoms; when the number of copper atoms is higher than eight, a surface plasmon-like peak appears at ∼520 nm. Based on the fundamental, elemental properties of Au and Cu, we predict a mixed atomic ordering and incorporation into the Au12 and Au 42 shells of the proposed icosahedral structured model. Alloy nanomolecules reported here could have potential applications in the field of catalysis and optical sensors.

Inhalable Nanocomposites And Anticancer Agents For Cancer Therapy, Nathanael A. Stocke

Theses and Dissertations--Chemical and Materials Engineering

Cancer is designated as the leading cause of mortality worldwide and lung cancer is responsible for nearly 30% of all cancer related deaths. Over the last few decades mortality rates have only marginally increased and rates of recurrence remain high. These factors, among others, suggest the need for more innovative treatment modalities in lung cancer therapy. Targeted pulmonary delivery is well established for treating pulmonary diseases such as asthma and provides a promising platform for lung cancer therapy. Increasing local deposition of anticancer agents (ACAs) and reducing systemic exposure of these toxic moieties could lead to better therapeutic outcomes and …

A Molecular-Level View Of The Physical Stability Of Amorphous Solid Dispersions, Xiaoda Yuan

Theses and Dissertations--Pharmacy

Many pharmaceutical compounds being developed in recent years are poorly soluble in water. This has led to insufficient oral bioavailability of many compounds in vitro. The amorphous formulation is one of the promising techniques to increase the oral bioavailability of these poorly water-soluble compounds. However, an amorphous drug substance is inherently unstable because it is a high energy form. In order to increase the physical stability, the amorphous drug is often formulated with a suitable polymer to form an amorphous solid dispersion. Previous research has suggested that the formation of an intimately mixed drug-polymer mixture contributes to the stabilization …

Determination Of The Structure Of Sphingomyelin By Tandem Mass Spectrometry And Matrix - Assisted Laser Desorption/Ionization, Antonio Ganios

Williams Honors College, Honors Research Projects

Mass spectrometry is a method that uses masses to determine the structure of a compound. This is completed by first charging the compound until it is a cation or anion, and then its molecular weight can be determined by measuring a mass to charge ratio. The focus of this study was determination of sphingomyelin’s structure. The purpose of this was that sphingomyelin has been shown to play a critical role in many biological pathways and being able to identify this lipid could prove to be beneficial for preventative medicine. Utilizing electrospray ionization (ESI) Quadruple-Time-of-flight (Q-TOF) mass spectrometry on a Waters …

Characterization Of Pm2.5 From Residential Woodstove Use For Source Apportionment Application, Virginia M. Porden

Graduate Student Theses, Dissertations, & Professional Papers

Results are presented for the comparative analysis of the PM_2.5 (Particulate Matter <2.5 µm) emissions from an EPA certified and a Traditional style wood stove using western larch. A total of 92 Quartz QMA 47mm filters were collected using a BGI PM_2.5 SSC (Sharp Cut Cyclone) sampler from each stove type and analyzed on a gas chromatograph-mass spectrometer against blank and deuterated internal standards. The results were analyzed using a Welch’s t-test (α > 0.05) to statistically differentiate between stove designs for temperature, mass, levoglucosan, resin acids (abietic and dehydroabietic), and polycyclic aromatic hydrocarbons [PAH] (acenaphthene, anthracene, benz(a)anthracene, pyrene, and retene). There was no statistical difference in levoglucosan PM_2.5 mass fraction between the stove types, yielding a mean levoglucosan fraction of 9.25% and 95% confidence interval of 8.43% …

Spectroscopic Studies On The Interaction Of Cetylpyridinium Bromide Monohydrate And Bromothymol Blue With Polymerized Silica, James Siegenthaler

All Master's Theses

The design and implementation of a controlled macromolecular chemical transport system could greatly advance switchable chemical reactions and be applicable for targeted drug delivery, intelligent inks, and nanotechnology. To better understand the mechanisms of function for a switchable macromolecular transport system, preliminary work has been completed that studies the transport of bromothymol blue (BB) facilitated by cetylpyridinium bromide monohydrate (CPBM) to a silica surface that has been modified with Poly(styrene-co-maleic anhydride), a pH switchable polymer. Ultraviolet spectroscopic trials were conducted measuring the absorbance of BB and CPBM at 3 pH levels and 3 different surface reactivity levels of …

Design And Development Of Bodipy-Based Fluorescent Probes For Sensing And Imaging Of Cyanide, Zn (Ii) Ions, Lysosomal Ph And Cancer Cells, Jingtuo Zhang

Dissertations, Master's Theses and Master's Reports - Open

BODIPY (4,4-Difluoro-3a,4a-diaza-s-indacene) dyes have gained lots of attention in application of fluorescence sensing and imaging in recent years because they possess many distinctive and desirable properties such as high extinction coefficient, narrow absorption and emission bands, high quantum yield and low photobleaching effect. However, most of BODIPY-based fluorescent probes have very poor solubilities in aqueous solution, emit less than 650 nm fluorescence that can cause cell and tissue photodamages compared with bio-desirable near infrared (650-900 nm) light. These undesirable properties extremely limit the applications of BODIPY-based fluorescent probes in sensing and imaging applications. In order to overcome these drawbacks, we …

Characterization Of Noncovalent Complexes Of Polyelectrolytes By Mass Spectrometry, Anthony J. Marino

Williams Honors College, Honors Research Projects

Various ions of poly-L-lysine and polystyrene sulfonic acid were successfully observed first within a matrix-assisted laser desorption/ionization mass spectrometer and subsequently in an electrospray ionization mass spectrometer. The successful ionization of these polymers allowed for studies to be performed on the noncovalent interactions between the two. Noncovalent interactions were effectively studied on both instruments, but further quantified using tandem mass spectrometry found within the MALDI system and ion-mobility mass spectrometry found within the electrospray ionization system. As a result of employing the use of ion-mobility, various different stoichiometries and charges of polyelectrolyte complexes could be distinguished.

Creation Of A Portable, 3d-Printable, Iphone-Compatible Spectrophotometer, Elise K. Grasse

Williams Honors College, Honors Research Projects

Spectroscopy is a widely used chemical and medical analysis tool. While spectrophotometers are commonly found in many universities and laboratories, they are not available to all high schools or laboratories in developing countries. The objective of this project was to design a high-quality, 3D-printable, iPhone-compatible spectrophotometer that uses a cell phone camera and interface to collect data. The created 3D-print file will be available to anyone with access to a 3D printer which are increasingly found in many laboratories and schools across the country. A low cost pre-printed kit will also be made for those without access to a 3D …

Electronic Structures And Electronic Spectra Of All-Boron Fullerene B40, Rongxing He, Xiao Cheng Zeng

Xiao Cheng Zeng Publications

This study is motivated by the recent discovery of the first all-boron fullerene analogue, a B₄₀ cluster with D_2d point-group symmetry, dubbed borospherene (Nat. Chem., 2014, 6, 727). Insight into the electronic structures and spectral properties of B₄₀ is timely and important to understand the borospherene and the transition from open-ended plate or ribbon-like structures to a hollow-cage structure at B₄₀. Optimized geometries of borospherene B₄₀ for both the ground state and the first excited state allow us to compute spectral properties including UV-vis absorption, infrared (IR) and Raman spectra. Highly resolved absorption and …