Chemistry Commons^™

Gc Verification Of The Spacecraft Atmosphere Monitor, Jessica S. Castro, Richard D. Kidd, Jeffrey D. Hein

STAR Program Research Presentations

International Space Station crew members face the unique challenge of maintaining air quality due to the volatile organic compounds (VOCs) that have the potential to accumulate at unsafe levels. The Spacecraft Atmosphere Monitor (SAM) is a miniature gas chromatograph/mass spectrometer (GCMS) designed to measure major constituents (such as N₂, O₂ and CO₂) and trace VOCs within the cabin of the spacecraft. The gas chromatograph is responsible for separating the sample into its components in order to be characterized. The oven of the gas chromatograph must reach a temperature of 150°C in order to heat constituents …

Using In Situ Liquid Single Photon Ionization Mass Spectrometry (Spi-Ms) To Probe Lithium Polysulfide Electrolyte In Motion, Aala M. Al Hasan, Jiachao Yu, Juan Yao, Vijayakumar Murugesan, Manjula Nandasiri, Xiao-Ying Yu

STAR Program Research Presentations

The solid-liquid (s-l) interface is the most common interface encountered in electrochemical systems. The s-l interface has wide applications in energy storage, catalysis, and material sciences. In situ studies of chemical reactions taking place on the s-l interfaces can further our understanding of electron transfer and link to real-world device functions under challenging conditions. Direct probing of the solid electrode and liquid electrolyte interface has been realized using a vacuum compatible electrochemical microfluidic reactor, system for analysis at the liquid vacuum interface (SALVI) with time-of-flight secondary ion mass spectrometry (ToF-SIMS). Most recently, the electrochemical version of SALVI was integrated to …

Development Of A Primary Ion Column For Mass Spectrometry-Based Surface Analysis, Raul A. Villacob

FIU Electronic Theses and Dissertations

Secondary Ion Mass Spectrometry (SIMS) is a powerful technique for high spatial resolution chemical mapping and characterization of native surfaces. The use of massive cluster projectiles has been shown to extend the applicable mass range of SIMS and improve secondary ion yields 100 fold or beyond. These large projectiles however, present a challenge in terms of focusing due to the initial spatial and kinetic energy spreads inherent to their generation. In the present work, we describe the development and construction of a novel primary ion (PI) column employing a gold nanoparticle – liquid metal ion source (AuNP-LMIS) and the coupling …

The Application Of Hydrogen/Deuterium Exchange And Covalent Labeling Coupled With Mass Spectrometry To Examine Protein Structure, Nicholas B. Borotto

Doctoral Dissertations

Thorough insight into a protein’s structure is necessary to understand how it functions and what goes wrong when it malfunctions. The structure of proteins, however, is not easily analyzed. The analysis must take place under a narrow range of conditions or risk perturbing the very structure being probed. Furthermore, the wide diversity in size and chemistry possible in proteins significantly complicates this analysis. Despite this numerous methods have been developed in order to analyze protein structure. In this work, we demonstrate that mass spectrometry (MS)-based techniques are capable of characterizing the structure of particularly challenging proteins. This is done through …

The Utilization Of Liquid Chromatography Tandem Mass Spectrometry And Related Techniques For The Analysis And Identification Of Emerging Contaminants In Aqueous Matrices, Matthew Reichert

Dissertations

Environmental pollutants can be found in many ecosystems and cover many different compound classes. The Environmental Protection Agency is responsible for monitoring and regulating several of these classes of compounds which daily enter the environment. However, there are still hundreds, if not thousands, of compounds present in the environment which have yet to be regulated or even identified. The discovery and identification of these unknown emerging pollutants is crucial for the prevention of potential human health risks and irreversible ecological damage.

The research presented is divided into two projects. The first part of this research investigates the disinfectant 3-Bromo-1-chloro-5,5-dimethylhydantoin, which …

Towards Structural Determination Of Human Α1-Glycine Receptor Allostery, Rathna Jyothi Veeramachaneni

Electronic Theses and Dissertations

Recent advances in technology have led to the determination of numerous notable structures of membrane proteins. While they provide valuable information about the structure of membrane proteins these studies often provide static images with potentially limited dynamics, and structural determination often requires truncation of flexible regions, and often utilizes bacterial homologs given the need for stable, heterologous overexpression. In order to better understand allostery at a molecular level, state-dependent crosslinking studies coupled with multidimensional mass spectrometry (MS) were conducted on glycine receptor (GlyR) stabilized in different allosteric states. Predominant allosteric states were stabilized using wild type or mutated receptor in …

Interactions Of The Naphthalene Radical Cation With Polar And Unsaturated Molecules In The Gas Phase, Sean P. Platt

Theses and Dissertations

Characterizing the interactions of solvent molecules with ions is fundamental in understanding the thermodynamics of solution chemistry. These interactions are difficult to observe directly in solution because the number of solvent molecules far exceed that of ions. This lend the gas phase to be the ideal medium in the study ion-solvent interactions on a molecular level. Ionized polycyclic aromatic hydrocarbon (PAH) molecules can readily form hydrogen bonds with neutral solvent molecules in aqueous and interstellar medium. Previous research has been done for stepwise solvation of small molecules such as benzene⁺, pyridine, and phenylacetylene. The similarity in these results …

Gold And Silver Alloy Nanoparticles: Synthesis, Characterization And Atomic Structure, Chanaka Kapila Kumara

Electronic Theses and Dissertations

Nanotechnology is an emerging field of science with applications in digital electronics, medicine, catalysis and energy. Gold nanoparticles are nanomaterials that have less than 100 nm at least in one dimension. The composition and the structure/geometry of the nanoparticles determine the chemical properties and reactivity. Modern research focus on method development in atomically monodisperse nanoparticle synthesis. This dissertation describes the method development for synthesis and isolation of atomically precise gold and gold-silver alloy nanoparticles and their comprehensive characterization and atomic structure investigation. Chapter one offers an introduction to the synthesis and isolation methods. These nanoparticles can be represented in the …

Establishing Chemical Mechanisms And Estimating Phase State Of Secondary Organic Aerosol From Atmospherically Relevant Organic Precursors, Shashank Jain

Graduate College Dissertations and Theses

Organic aerosol (OA) is a ubiquitous component of atmospheric particulate that influences both human health and global climate. A large fraction of OA is secondary in nature (SOA), being produced by oxidation of volatile organic compounds (VOCs) emitted by biogenic and anthropogenic sources. Despite the integral role of SOA in atmospheric processes, there remains a limited scientific understanding of the chemical and physical changes induced in SOA as it ages in the atmosphere. This thesis describes work done to increase the knowledge of processes and properties of atmospherically relevant SOA.

In the work presented in this thesis, I have worked …

Tip-Enhanced Laser Ablation Sample Transfer For Mass Spectrometry, Chinthaka Aravinda Seneviratne

LSU Doctoral Dissertations

In this research, atomic force microscope tip-enhanced laser ablation mass spectrometry (AFM TELA-MS), an ambient sub-micrometer scale sampling method for offline MS was developed. AFM TELA was used to transfer molecules from thin films to a suspended silver wire for off-line mass spectrometry using laser desorption ionization (LDI) and matrix-assisted laser desorption ionization (MALDI). An AFM with a 30 nm radius gold-coated silicon tip was used to image the sample and to hold the tip 15 nm from the surface for material removal using a pulsed Nd:YAG laser, which provides output at wavelengths of 532 nm in the visible, 1064 …