Physical Sciences and Mathematics Commons^™

Assessment Of The Toxicity Of Legacy And Next-Generation Perfluoroalkyl Substances (Pfas) In Early-Life Stages Of Freshwater And Marine Fish, Kiflom Gebreab

FIU Electronic Theses and Dissertations

Per- and polyfluoroalkyl substances (PFASs) are a group of synthetic surfactants that have utilized for several decades in a wide range of industrial and manufacturing applications. Owing to their high chemical stability, PFAS are widespread and persistent in the environment, and have been shown to be bioaccumulative in diverse organisms including plants, wildlife, and humans. Exposure to PFASs has been linked to a range of documented toxic and/or adverse effects in relation to human and animal health. The potential environmental health and ecotoxicity of next-generation PFAS remain unclear. In the present study, toxicity, and bioconcentration potential, of several perfluoroether carboxylic …

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 …

The Coordination Chemistry Of The Rhodizonate Dianion And Its Decomposition Products, Joshua A. Silverman

FIU Electronic Theses and Dissertations

The rhodizonate dianion is of importance for forensic testing, specifically with regard to the sodium rhodizonate test for lead in gunpowder residues. In an effort to understand this test from a chemical perspective, the coordination of rhodizonate and its decomposition products, croconate and oxalate, with several metals has been investigated with a variety of structural and spectroscopic methods.

FT-IR data of the three sequential steps of the sodium rhodizonate test show coordination between Pb(II) atoms, tartrate anions, and rhodizonate dianions, with the tartrate being substituted for Cl^- once a 5% HCl solution is added to produce the confirmatory blue-purple …

Lanthanide Interactions With Ligands And Biomolecules: Spectroscopic And Extraction Studies, Setareh Sakhdari

FIU Electronic Theses and Dissertations

Lanthanides (Ln), also known as rare earth metals, have been utilized for industrial and biological purposes and are commonly encountered in the 3+ oxidation state as Ln³⁺. The presence of Ln in spent nuclear fuel introduces problems during the transmutation and partitioning of actinides (An) due to the Ln high neutron cross-sections. Therefore, designing ligands for Ln³⁺ complexation, can be helpful for their separation from An³⁺ in nuclear technology. Also, the biomimetic roles of Ln³⁺ could be suitable for studying the biological macromolecules, such as the Ca²⁺-binding EF-hand proteins that are otherwise inaccessible …

Dipicolinamide Ligands And Analogs For Lanthanides (Ln), Actinides (An) And Mercury (Hg) For Application To Nuclear Fuel Cycle Separations And Waste Management, Ingrid Lehman-Andino

FIU Electronic Theses and Dissertations

Spent nuclear fuel (SNF) – or used nuclear fuel (UNF) – contains long-lived minor actinides such as ²⁴¹Am, ²⁴⁵Cm, and ²³⁷Np, together with fission products that include lanthanides. Minor actinides are responsible for much of the radiotoxicity and heat generation that limits the capacity of geological repositories. Thus, removing minor actinides from UNF can reduce storage time required for decay to natural levels of activity by several orders of magnitude. Actinide(An)/Lanthanide(Ln) separation processes via solvent extraction by selective complexation with organic or aqueous ligands have to overcome difficulties due to similarities in their ionic radii for the …

Towards Trigonal Prismatic Hexanuclear Copper Complexes For Catalytic Water Oxidation, David I. Kreiger

FIU Electronic Theses and Dissertations

Our planet is running out of energy resources and traditional renewables are not easily transported nor will be sufficient to cover the void left by fossil fuels. Therefore, a new energy storage system needs to be adopted. The medium with highest energy density that is readily available is hydrogen from water. However, to access hydrogen, water needs to be oxidized and water oxidation catalysts (WOCs) will be required for widespread adoption. In pursuit of WOCs, several hexauclear copper complexes were synthesized and characterized, including the isolation and characterization of a mixed-valent Cu₆ (formally, Cu^II₅Cu^III) …

Elemental Analysis Of Adhesive Tapes By Laser-Based Methods, Claudia Martinez Lopez

FIU Electronic Theses and Dissertations

Adhesive tapes are a common type of evidence involved in violent crimes and national security threats. This research evaluated the utility of LA-ICP-MS and LIBS for the characterization of the trace elemental signature in adhesive tapes for forensic comparisons. LA-ICP-MS and LIBS methods were developed, for the first time, for the qualitative and quantitative analysis of adhesive tapes.

The backings of 90 black electrical tapes, previously characterized by conventional techniques (physical examination, IR, Py-GC-MS, and SEM-EDS), were analyzed by LA-ICP-MS to evaluate the ability of the technique to discriminate samples originating from different sources and to associate pieces of tapes …

Synthesis And Characterization Of Fe8-Based Materials As Electron Acceptors For Solar Energy Applications, Alan J. Rodriguez-Santiago

FIU Electronic Theses and Dissertations

The urgent need to find alternative sources of energy has been recognized as a major challenge of the 21st century. Many ideas have been proposed, but harvesting the energy of the Sun has been identified by many as the most promising alternative to satisfy the world’s increasing energy demand. Among the current technologies to harness solar energy, photovoltaics and artificial photosynthesis (photocatalysis) stand out. Although very different in their strategies, both technologies entail a core principle, the generation of a charge-separated state. To this end, both methods employ electron acceptors that will receive the photo-electron; in most cases this role …

Ultrahigh Speed Direct Pcr: A Method For Obtaining Y-Str And Str Based Genotypes In Under 20 Minutes, Georgiana C. Gibson-Daw

FIU Electronic Theses and Dissertations

There are many situations in forensic DNA typing where the time it takes to identify an individual is critical. Examples include suspects under arrest and individuals detained at ports of entry. It is also important to identify victims quickly when dealing with mass disasters such as terrorist attacks, airplane crashes and natural disasters in order to notify families. The goal of this project was to develop an ultrafast method for screening saliva samples through the use of rapid direct PCR coupled to microfluidic separation and detection.

Fast amplification was achieved through the use of high speed thermocyclers and the experimental …

The Creation And Evaluation Of Novel Canine Training Aids For Cocaine Using Molecularly Encapsulated Sol-Gel Polymers And An Investigation Of Canine Field Accuracy, Michelle Cerreta

FIU Electronic Theses and Dissertations

Biological detectors, such as canines, are valuable tools used for the rapid identification of illicit materials. However, recent increased scrutiny over the reliability, field accuracy, and the capabilities of each detection canine is currently being evaluated in the legal system. For example, the Supreme Court case, State of Florida v. Harris, discussed the need for continuous monitoring of canine abilities, thresholds, and search capabilities. As a result, the fallibility of canines for detection was brought to light, as well as a need for further research and understanding of canine detection. This study is two-fold, as it looks to not only …

Development Of Presumptive And Confirmatory Analytical Methods For The Simultaneous Detection Of Multiple Improvised Explosives, Kelley L. Peters

FIU Electronic Theses and Dissertations

In recent years, there has been a dramatic increase in the use of improvised explosive devices (IEDs) due to ease of synthesis and improved controls placed on commercial/military explosives. Commonly used materials for IED preparations include fertilizers and industrial chemicals containing oxidizers such as ClO₃^-, ClO₄^-, and NO₃^-, as well as other less stable compounds, such as peroxides. Due to these materials having a wide range of volatility, polarity, and composition, detection can be challenging, increasing the amount of time before any analytical information on the identity of the explosive can …