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Full-Text Articles in Physical Sciences and Mathematics
Evaluation And Improvement Of Capillary Microextraction Of Volatiles Coupled To Gas Chromatography-Mass Spectrometry For The Analysis Of Ignitable Liquid Residues In Fire Debris, Michelle Nikole Torres
Evaluation And Improvement Of Capillary Microextraction Of Volatiles Coupled To Gas Chromatography-Mass Spectrometry For The Analysis Of Ignitable Liquid Residues In Fire Debris, Michelle Nikole Torres
FIU Electronic Theses and Dissertations
A key aspect of fire debris analysis is the ability to extract the remnants of an ignitable liquid from a matrix with a high degree of reliability and sensitivity. Although there are several robust, standardized methods, there is no single technique universally applicable to casework. In this work a novel extraction technique – Capillary Microextraction of Volatiles (CMV) – has been applied, for the first time, for ignitable liquid residue (ILR) extraction. A 20-minute dynamic sampling laboratory protocol from traditional 1 L paint cans was established and optimized based upon ASTM guidelines. The development of new adsorption phases for CMV …
Interrogation Of Ion-Neutral Complexes By Trapped Ion Mobility-Mass Spectrometry And Theoretical Calculations, Alan A. Mckenzie Coe
Interrogation Of Ion-Neutral Complexes By Trapped Ion Mobility-Mass Spectrometry And Theoretical Calculations, Alan A. Mckenzie Coe
FIU Electronic Theses and Dissertations
In the present study, the fundamentals of molecular ion trapping and the application of trapped ion mobility spectrometry coupled to mass spectrometry (TIMS-MS) to the separation and identification of molecular components in complex mixtures are shown. In particular, ion-neutral complexes lifetimes, relative stability, binding energies and candidate structures are described for common explosives during TIMS-MS, as well as the effect of the micro-environment, during complex sample analysis. A novel TIMS-MS workflow was developed for the detection of both inorganic residues (IGSR; inorganic gunshot residues) and organic residues (OGSR) of firearm discharge residue from skin swabs, capable of high specificity and …
Conformational Dynamics Of Biomolecules By Trapped Ion Mobility Spectrometry Dynamics, Juan Camilo Molano-Arévalo
Conformational Dynamics Of Biomolecules By Trapped Ion Mobility Spectrometry Dynamics, Juan Camilo Molano-Arévalo
FIU Electronic Theses and Dissertations
One of the main goals in structural biology is to understand the folding mechanisms and three-dimensional structure of biomolecules. Many biomolecular systems adopt multiple structures as a function of their microenvironment, which makes them difficult to be characterized by traditional structural biology tools (e.g., NMR, X-ray crystallography). As an alternative, complementary tools that can capture and sample multiple conformations needed to be developed. In the present work, we pioneered the application of a new variant of ion mobility spectrometry, trapped ion mobility spectrometry (TIMS), which provides high mobility resolving power and the possibility to study kinetically trapped intermediates as a …
Discovery And Targeted Monitoring Of Biomarkers Using Liquid Chromatography, Ion Mobility Spectrometry , And Mass Spectrometry, Kendra J. Adams
Discovery And Targeted Monitoring Of Biomarkers Using Liquid Chromatography, Ion Mobility Spectrometry , And Mass Spectrometry, Kendra J. Adams
FIU Electronic Theses and Dissertations
The complexity of biological matrices makes the detection and quantification of compounds of interest challenging. For successful targeted or untargeted identification of compounds within a biological environment, the use of complementary separation techniques is routinely required; in many situations, a single analytical technique is not sufficient. In the present dissertation, a multidimensional analytical technique was developed and evaluated, a combination of new sample preparation/extraction protocols, liquid chromatography, trapped ion mobility and mass spectrometry (e.g., LC-TIMS-MS and LC-TIMS-MS/MS). The performance of these techniques was evaluated for the detection of polybrominated diphenyl ethers metabolites, polychlorinated biphenyls metabolites in human plasma, opioid metabolites …
Qualitative Analysis For The Characterization And Discrimination Of Printing Inks, Rhett J. Williamson
Qualitative Analysis For The Characterization And Discrimination Of Printing Inks, Rhett J. Williamson
FIU Electronic Theses and Dissertations
Improvements in printing technology and the wide accessibility of advanced printers has resulted in an increase in counterfeiting. Of particular interest to forensic document examiners, ink analysis of security documents has emerged as an important tool for the analysis, comparison, and association of inks to a potential production source. In this study, methods were developed for Py-GC/MS, ATR-FTIR, DART-MS, and MALDI-MS analyses of printing inks of four classes: 78 inkjet inks, 76 toners, 79 offset inks, and 86 intaglio inks in order to generate information on the organic chemical characterization of the inks to determine the ability to associate and …
Development Of A Primary Ion Column For Mass Spectrometry-Based Surface Analysis, Raul A. Villacob
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 …
Determination Of Extracellular Molecules Produced By Vibrio Harveyi Using Ms/Ms, Jose G. Roble
Determination Of Extracellular Molecules Produced By Vibrio Harveyi Using Ms/Ms, Jose G. Roble
FIU Electronic Theses and Dissertations
Quorum sensing (QS) is a process that allows bacteria to sense the population density of cells around them by communicating with each other via autoinducer molecules. This cross-communication is crucial in the regulation of bacterial processes such as bioluminescence, virulence, and biofilm formation. Previous research by Milburn and Makemson on Vibrio harveyi suggested that in addition of the known biosynthesis of three well-characterized autoinducers, dozens of unknown molecules are also produced and released to the environment by V. harveyi. This study was performed using electrospray tandem mass spectrometry with the purpose of detection and characterization of the extracellular molecules …