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Dissertations / Theses on the topic 'Forensic Science, Analytical Chemistry, Nanoparticles'
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1
Dominguez, Kimberly. "Leaching of Silver Nanoparticles from Textiles." Ohio University Art and Sciences Honors Theses / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=ouashonors155690445799457.
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Doctor, Erika L. "Development of a Surface-Enhanced Raman Spectroscopy Method for the Detection of Benzodiazepines in Urine." FIU Digital Commons, 2014. http://digitalcommons.fiu.edu/etd/1642.
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Benzodiazepines are among the most prescribed compounds for anti-anxiety and are present in many toxicological screens. These drugs are also prominent in the commission of drug facilitated sexual assaults due their effects on the central nervous system. Due to their potency, a low dose of these compounds is often administered to victims; therefore, the target detection limit for these compounds in biological samples is 10 ng/mL. Currently these compounds are predominantly analyzed using immunoassay techniques; however more specific screening methods are needed.
The goal of this dissertation was to develop a rapid, specific screening technique for benzodiazepines in urine samples utilizing surface-enhanced Raman spectroscopy (SERS), which has previously been shown be capable of to detect trace quantities of pharmaceutical compounds in aqueous solutions. Surface enhanced Raman spectroscopy has the advantage of overcoming the low sensitivity and fluorescence effects seen with conventional Raman spectroscopy. The spectra are obtained by applying an analyte onto a SERS-active metal substrate such as colloidal metal particles. SERS signals can be further increased with the addition of aggregate solutions. These agents cause the nanoparticles to amass and form hot-spots which increase the signal intensity.
In this work, the colloidal particles are spherical gold nanoparticles in aqueous solution with an average size of approximately 30 nm. The optimum aggregating agent for the detection of benzodiazepines was determined to be 16.7 mM MgCl2, providing the highest signal intensities at the lowest drug concentrations with limits of detection between 0.5 and 127 ng/mL. A supported liquid extraction technique was utilized as a rapid clean extraction for benzodiazepines from urine at a pH of 5.0, allowing for clean extraction with limits of detection between 6 and 640 ng/mL. It was shown that at this pH other drugs that are prevalent in urine samples can be removed providing the selective detection of the benzodiazepine of interest.
This technique has been shown to provide rapid (less than twenty minutes), sensitive, and specific detection of benzodiazepines at low concentrations in urine. It provides the forensic community with a sensitive and specific screening technique for the detection of benzodiazepines in drug facilitated assault cases.
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Harries, Megan Elizabeth. "Vapor-liquid Equilibria Pertaining to the Study of Alternative Fuels and the Forensic Analysis of Chemical Evidence." Thesis, University of Colorado at Boulder, 2018. http://pqdtopen.proquest.com/#viewpdf?dispub=10843874.
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<p> Measurement of the vapor-liquid equilibrium (VLE) of fluid mixtures with many components presents a challenge. Data describing such mixtures, like fuels, are important for the development of alternative energy sources and to support forensic science, but there is a lack of suitable instrumentation to provide data with reasonable uncertainty for mixtures with many components. In this thesis, three different techniques for fluid characterization are explored: the advanced distillation curve (ADC), the advanced distillation curve with reflux (ADCR), and PLOT-cryoadsorption. Two pyrolysis fuels similar to gasoline and diesel fuel made from polypropylene were studied with respect to volatility, composition, and energy content using the advanced distillation curve. The diesel fuel demonstrated volatility very similar to previously measured diesel fuels. The gasoline was less volatile than petroleum-derived counterparts and did not meet specifications.</p><p> Two pyrolysis crude oils made from ponderosa pine and dairy manure were assessed using the ADC coupled to an approach for characterizing fluids with multiple, immiscible liquid phases. Both oils contained high water levels and would require further refinement before use. The organic phases of each oil contained components indicative of the feedstock used.</p><p> A modification of the ADC method, the advanced distillation curve with reflux, was introduced as an approach to measuring the VLE of fluids with many components. The ADCR additionally approximates the weathering of an ignitable liquid that occurs during an arson fire and measures VLE across a range of weathered conditions. The method was demonstrated using two simple mixtures. The measurements agreed well with models, indicating that ADCR is a suitable VLE metrology.</p><p> Vapor-liquid equilibrium data are crucial for interpreting the results of headspace characterization used often in forensic science. One headspace method, portable PLOT-cryoadsorption, was tested in a series of experiments in the laboratory and then deployed for the first time in a field environment that simulated a cargo container. The technology was found to be rapid and sensitive to a variety of compounds of interest to forensic science. Each of the three techniques described in this thesis contribute valuable property data for multicomponent mixtures, towards the development of high-quality predictive models.</p><p>
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Rex, Matthew. "ROOM TEMPERATURE FLUORESCENCE SPECTROSCOPY AS A TOOL FOR THE FORENSIC TRACE ANALYSIS OF TEXTILE FIBERS." Doctoral diss., University of Central Florida, 2009. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/4355.
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ABSTRACT Trace textile fiber evidence is found at numerous crime scenes and plays an important role in linking a suspect to the respective scene. Several methods currently exist for the analysis of trace fiber evidence. Microscopy provides information regarding the fibers material, color and weave. For more detailed chemical analysis chromatographic methods are employed and for discrimination between dyes, liquid chromatography coupled with mass spectrometry (LC-MS) is currently the method providing the most discrimination. These methods have primarily focused on the dyes used to color the fibers and have not investigated other components that can potentially discriminate among fibers. This dissertation deals with investigations into the fluorescence of the fiber dyes, (contaminants?) and the fibers themselves, as well as methodology for discriminating between fibers using fluorescence. Initial systematic analysis was conducted on dye standards and extracts taken from fibers colored with the respective dyes of interest. Absorbance, excitation and fluorescence spectra were compared between standards and extracts to determine the optimal area of the fiber to investigate: dyes, fluorescent impurities or the whole fiber. High performance liquid chromatography investigations were performed to give detailed information on the number of dye and fluorescent components present in extracts. Our investigations then focused on the best room-temperature fluorescence (RTF) data format for analysis and discrimination of fiber samples. An excitation emission matrix (EEM) was found to give the greatest amount of spectral information and provide the highest level of discrimination. Successful discrimination between non similar and similar fibers was achieved with the aid of Chemometric analysis. The level of discrimination obtained via RTF-EEM spectroscopy was sufficient to differentiate among fibers obtained from two separate cloths of the same material and colored with the same dye reagent. Final studies deal with examining exposure of the fiber to various environmental contaminants. Clothing fibers are typically exposed to myriad numbers of contaminants, from food stains to cigarette smoke. The challenge then becomes detecting fluorescence signals from trace amounts of these environmental contaminants. We demonstrate the detection and classification of polycyclic aromatic hyrdrocarbons (PAH) present on fibers after exposure to cigarette smoke. This dissertation also investigates the change in fluorescence emission after laundering fibers numerous times. The main drawback of chemical analysis of fibers is the destructive nature of the methods. To extract a dye or contaminant from a fiber essentially destroys the evidence. This leaves the investigator without their original sample in the courtroom. This also provides a finite amount of sample for testing and analysis. This is true of chromatographic methods and for the method detailed in this dissertation which makes use of extracts taken from fiber samples. Lastly, we propose an instrumental setup coupling a microscope to a spectrofluorimeter for the purpose of taking EEM directly from a fiber sample. This setup makes use of the superior optics of the microscope for focusing excitation light onto the fiber sample. Initial studies have been performed on extracts from a single textile fiber and EEM collected from said fiber.<br>Ph.D.<br>Department of Chemistry<br>Sciences<br>Chemistry PhD
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Atnagulov, Aydar. "Application of Mass Spectrometry to the Characterization of Core and Ligand Shell Modifications of Silver Molecular Nanoparticles." University of Toledo / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1501860803445199.
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Jean, Deok-im. "CORE-SHELL NANOPARTICLES: SYNTHESIS, ASSEMBLY, AND APPLICATIONS." Miami University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=miami1374848575.
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Martinez, Lopez Claudia. "Elemental Analysis of Adhesive Tapes by Laser-Based Methods." FIU Digital Commons, 2018. https://digitalcommons.fiu.edu/etd/3862.
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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 originating from the same roll. The discrimination for the LA-ICP-MS analysis of the 90 samples was found to be 93.9%, greater than the discrimination found using SEM-EDS (87.3%). Moreover, 100% correct association resulted for the control samples evaluated in this study.
The analysis of tapes by LIBS allowed to separate pairs of tapes that were not previously distinguished by LA-ICP-MS by detecting differences in lithium, calcium, and potassium.
The potential of normalization strategies was evaluated for LIBS spectral and statistical comparisons.
Two quantitative analysis methods were developed for the analysis of tapes and other polymers. These quantitative methods can help in creating and populating databases that can lead to the use of likelihood ratios and the development of standard methods of analysis and interpretation for tape evidence.
Two interlaboratory trials including 7 operational and research laboratories were completed as part of this study. SEM-EDS resulted in 16.7% and 12.5% false positive rates for interlaboratory tests #1 and #2, respectively. Up to 7 and 8 elements were detected by SEM-EDS for interlaboratory test #1 and #2, respectively. LIBS and LA-ICP-MS resulted in no false positives or false negatives. In addition, increased characterization of the samples was obtained by detecting up to 17 elements by LIBS and 32 elements by LA-ICP-MS. The increased sensitivity and selectivity of LIBS and LA-ICP-MS methods has been shown to distinguish tapes originating from different sources, and to correctly associate tapes belonging to the same rolls in different laboratories and by different analysts.
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Williamson, Rhett J. "Qualitative Analysis for the Characterization and Discrimination of Printing Inks." FIU Digital Commons, 2016. http://digitalcommons.fiu.edu/etd/3055.
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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 discriminate the inks for uses in security document examinations. The suite of analytical techniques evaluated in the study focused on having the following analytical characteristics: 1) rapid analysis time, 2) little-to-no sample preparation, 3) minimal destructiveness to the sample, 4) allow for association of inks with the same source of origin as well as discrimination of inks originating from different sources. As a result of this study, a novel searchable library database of inks was developed for use with each analytical chemical method that allows for data fusion.
Py-GC/MS analysis was used to achieve >63% discrimination of toner inks on the basis of the characterization of polymer degradation products. The combination of a protocol implementing first ATR-FTIR and subsequently DART-MS analysis resulted in >96% discrimination for toners, 95% for inkjet, >92% for offset, and >54% for intaglio. In addition, a case study was performed using DART-MS to illustrate its utility as a tool for ink analysis in document examination. The results of MALDI-MS analyses from two different instruments resulted in >90% discrimination of a subset of all inks by characterizing the colorant molecules present in ink formulations. A study characterizing luminescent compounds present in the formulation of inks in crossed-line intersections was performed using a combination of MALDI-MS, LC-MS, and TLC. Overall, it was shown that the combination of analytical techniques included within this dissertation can provide information on the organic chemical composition of four classes of printing inks, which is useful for the future of document examination.
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Hoffman, Tricia Marie. "The Use of Elemental Databases in Forensic Science: Studies on Vehicle Glass Interpretation and Milk Powder Provenancing." FIU Digital Commons, 2018. https://digitalcommons.fiu.edu/etd/3812.
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The first study focuses on the development of a laser based method for the elemental analysis of solid milk powder. Milk powder samples originating from five different countries were analyzed to determine any geographic differences. A LA-ICP-MS method was developed and compared to k0-INAA for several milk samples as well as a reference sample. Precision of 10% RSD or better and a bias of 10% was achieved for both techniques for most elements with LA-ICP-MS producing lower limits of detection (~ 1 ppm) for Sr. The comparison of LA-ICP-MS to k0-INAA showed overlap of the 95% confidence intervals for all comparison samples. The data for 68 authentic milk powder samples representing 5 different countries (Argentina, Russia, Singapore, Slovenia, and the United States) was collected and used as a preliminary database. Principle component analysis (PCA) shows different groupings for the United States, Argentina, Singapore, and Slovenia. However the large number and geographic distribution of samples from Russia were not able to be distinguished from the samples from the United States and Slovenia.
The second study focuses on the use of trace element databases for the objective interpretation of forensic glass evidence. Ten laboratories conducting analysis of glass participated in three inter-laboratory exercises. The aims of these exercises were to evaluate the use of a standard method for the analysis and comparison of glass evidence and to investigate different statistical approaches for interpreting results. Elemental analysis was performed on 420 vehicle windshield samples collected from 210 different vehicles representing manufacturing dates between 2004-2017 and 26 vehicle manufacturers. Using a variation of a previously reported comparison criterion for comparing samples to a database, the false exclusion rate and false inclusion rate for the new vehicle database were calculated to be 1.9% and 0.1 % respectively. This criterion was used to calculate the frequency of an elemental profile for the case scenarios distributed as part of the inter-laboratory exercises. Similarities were observed between labs that calibrated their data the same way, thus showing it is possible for labs to use a central database.
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Peebles, Brian Christopher. "Pulmonary Toxicity of Manufactured Nanoparticles." The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1274902471.
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Cobbs, Ashley L. "Detection of Barium and Strontium Ions in Water Utilizing Functionalized Silver Nanoparticles." Ohio University Honors Tutorial College / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ouhonors1588098171596986.
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Casper, Brent. "DEVELOPMENT OF AN EXTRACTION METHOD FOR THE MASS SPECTRAL ANALYSIS OF ORGANIC GUNSHOT RESIDUE FROM CLOTHING." UKnowledge, 2015. http://uknowledge.uky.edu/chemistry_etds/48.
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This dissertation will focus on the extraction of volatile organic compounds associated with gunshot residue from articles of clothing, followed by analysis with mass spectrometry. During the discharge of a weapon, a cloud of volatile organic gunshot residue (OGSR) is dispersed around a firearm. This will create a high probability of transfer between the OGSR and the clothing of individuals who are near a discharged weapon.
The first part of this dissertation will be the development of a method for removal of volatile OGSR from articles of clothing. Extraction of OGSR will be completed by solid phase microextraction (SPME), followed by separation and analysis by gas chromatography-mass spectrometry (GC/MS). Many parameters will require optimization for proper extraction of OGSR from articles of clothing. Following development of a SPME procedure, figures of merit were determined such as linearity and limits of detection/quantification, obtaining levels of detection of 0.206 ng/cm2 on a 100 cm2 cotton cloth. Applications of this extraction method were investigated including the determination of the distance OGSR travels from a discharged weapon and the extraction of OGSR with different clothing materials by SPME.
The second part of this dissertation will focus on the development of an on-line solvent extraction method for removal of OGSR from articles of clothing, followed by analysis with paper spray mass spectrometry. Issues using SPME of certain types of clothing materials required the development of an alternative method for removal of OGSR from articles of clothing. Use of an on-line solvent extraction technique of OGSR from articles of clothing followed by analysis with paper spray mass spectrometry allowed for detection of OGSR at comparable levels to a headspace SPME procedure. Use of paper spray with an ion trap mass spectrometer permitted the soft ionization of OGSR compounds followed by tandem mass spectrometry to obtain structural information.
Extraction of OGSR from articles of clothing has potential to determine if an individual was present during the discharge of a firearm. Extraction of OGSR from articles of clothing will provide an alternative to traditional methods of gunshot residue analysis currently in use.
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Abouomar, Ramadan. "SYNTHESIS AND THERMODYNAMICS OF NANOPARTICLES PREPARED BY SINGLE-CHAIN COLLAPSE OF SILOXANE-CONTAINING LINEAR AND HYPERBRANCHED POLYMERS." University of Akron / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=akron1574339777651288.
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Brittle, Seth William. "Bioavailability and Transformation of Silver Nanoparticles in the Freshwater Environment." Wright State University / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=wright1484594585990252.
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Sun, Xiaobo. "Forensic Applications of Gas Chromatography/Mass Spectrometry, High Performance Liquid Chromatography--Mass Spectrometry and Desorption Electrospray Ionization Mass Spectrometry with Chemometric Analysis." Ohio University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1329517616.
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Caraballo, Norma Iris. "Identification of Characteristic Volatile Organic Compounds Released during the Decomposition Process of Human Remains and Analogues." FIU Digital Commons, 2014. http://digitalcommons.fiu.edu/etd/1391.
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The manner in which remains decompose has been and is currently being researched around the world, yet little is still known about the generated scent of death. In fact, it was not until the Casey Anthony trial that research on the odor released from decomposing remains, and the compounds that it is comprised of, was brought to light. The Anthony trial marked the first admission of human decomposition odor as forensic evidence into the court of law; however, it was not “ready for prime time” as the scientific research on the scent of death is still in its infancy.
This research employed the use of solid-phase microextraction (SPME) with gas chromatography-mass spectrometry (GC-MS) to identify the volatile organic compounds (VOCs) released from decomposing remains and to assess the impact that different environmental conditions had on the scent of death. Using human cadaver analogues, it was discovered that the environment in which the remains were exposed to dramatically affected the odors released by either modifying the compounds that it was comprised of or by enhancing/hindering the amount that was liberated. In addition, the VOCs released during the different stages of the decomposition process for both human remains and analogues were evaluated. Statistical analysis showed correlations between the stage of decay and the VOCs generated, such that each phase of decomposition was distinguishable based upon the type and abundance of compounds that comprised the odor.
This study has provided new insight into the scent of death and the factors that can dramatically affect it, specifically, frozen, aquatic, and soil environments. Moreover, the results revealed that different stages of decomposition were distinguishable based upon the type and total mass of each compound present. Thus, based upon these findings, it is suggested that the training aids that are employed for human remains detection (HRD) canines should 1) be characteristic of remains that have undergone decomposition in different environmental settings, and 2) represent each stage of decay, to ensure that the HRD canines have been trained to the various odors that they are likely to encounter in an operational situation.
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Poudel, Chetan. "Inverted Linear Halbach Array for Separation of Magnetic Nanoparticles." Oberlin College Honors Theses / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=oberlin1400251699.
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Jantzi, Sarah C. "Elemental Analysis and Forensic Comparison of Soils by Laser-Induced Breakdown Spectroscopy (LIBS) and Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS)." FIU Digital Commons, 2013. http://digitalcommons.fiu.edu/etd/967.
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The elemental analysis of soil is useful in forensic and environmental sciences. Methods were developed and optimized for two laser-based multi-element analysis techniques: laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) and laser-induced breakdown spectroscopy (LIBS). This work represents the first use of a 266 nm laser for forensic soil analysis by LIBS.
Sample preparation methods were developed and optimized for a variety of sample types, including pellets for large bulk soil specimens (470 mg) and sediment-laden filters (47 mg), and tape-mounting for small transfer evidence specimens (10 mg). Analytical performance for sediment filter pellets and tape-mounted soils was similar to that achieved with bulk pellets.
An inter-laboratory comparison exercise was designed to evaluate the performance of the LA-ICP-MS and LIBS methods, as well as for micro X-ray fluorescence (μXRF), across multiple laboratories. Limits of detection (LODs) were 0.01-23 ppm for LA-ICP-MS, 0.25-574 ppm for LIBS, 16-4400 ppm for µXRF, and well below the levels normally seen in soils. Good intra-laboratory precision (≤ 6 % relative standard deviation (RSD) for LA-ICP-MS; ≤ 8 % for µXRF; ≤ 17 % for LIBS) and inter-laboratory precision (≤ 19 % for LA-ICP-MS; ≤ 25 % for µXRF) were achieved for most elements, which is encouraging for a first inter-laboratory exercise. While LIBS generally has higher LODs and RSDs than LA-ICP-MS, both were capable of generating good quality multi-element data sufficient for discrimination purposes.
Multivariate methods using principal components analysis (PCA) and linear discriminant analysis (LDA) were developed for discriminations of soils from different sources. Specimens from different sites that were indistinguishable by color alone were discriminated by elemental analysis. Correct classification rates of 94.5 % or better were achieved in a simulated forensic discrimination of three similar sites for both LIBS and LA-ICP-MS. Results for tape-mounted specimens were nearly identical to those achieved with pellets.
Methods were tested on soils from USA, Canada and Tanzania. Within-site heterogeneity was site-specific. Elemental differences were greatest for specimens separated by large distances, even within the same lithology. Elemental profiles can be used to discriminate soils from different locations and narrow down locations even when mineralogy is similar.
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Martinez, Vanessa. "The Optimization of Pressure Cycling Technology (PCT) for Differential Extraction of Sexual Assault Casework." FIU Digital Commons, 2016. http://digitalcommons.fiu.edu/etd/2999.
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A two-step protocol has been devised as a rapid and selective alternative to conventional differential extraction techniques with an increased recovery of DNA. The protocol involves pressure cycling with the Barocycler® NEP 2320 from Pressure Biosciences. Inc. in alkaline conditions for epithelial cell lysis and removal. This step is followed by alkaline lysis at 95º C for extraction of sperm cell DNA. At 1:1 or 2:1 female to male cell ratios, high selectivity and complete separation can be achieved. But at higher ratios, male allelic dropout is observed. This protocol has been modified to generate a clean male profile at a 20:1 cell ratio through optimization of NaOH concentration and inclusion of an additional pressure cycling step. Validation studies have been performed to assess the efficiency of this method under various conditions. An additional immunomagnetic cell capture pretreatment allowed for nearly complete separation at cell ratios of up to 200:1.
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An, Yan. "The Potential of Bulk and Amino-Acid Specific Isotope Ratio Mass Spectrometry of Human Hair in Forensic and Clinical Applications." Ohio University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1363701887.
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Thomas, Jennifer L. "Method Development for the Analysis of Smokeless Powders and Organic Gunshot Residue by Ultra Performance Liquid Chromatography with Tandem Mass Spectrometry." FIU Digital Commons, 2013. http://digitalcommons.fiu.edu/etd/1017.
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The goal of this project was to develop a rapid separation and detection method for analyzing organic compounds in smokeless powders and then test its applicability on gunshot residue (GSR) samples. In this project, a total of 20 common smokeless powder additives and their decomposition products were separated by ultra performance liquid chromatography (UPLC) and confirmed by tandem mass spectrometry (MS/MS) using multiple reaction monitoring mode (MRM). Some of the targeted compounds included diphenylamines, centralites, nitrotoluenes, nitroglycerin, and various phthalates. The compounds were ionized in the MS source using simultaneous positive and negative electrospray ionization (ESI) with negative atmospheric pressure chemical ionization (APCI) in order to detect all compounds in a single analysis. The developed UPLC/MS/MS method was applied to commercially available smokeless powders and gunshot residue samples recovered from the hands of shooters, spent cartridges, and smokeless powder retrieved from unfired cartridges. Distinct compositions were identified for smokeless powders from different manufacturers and from separate manufacturing lots. The procedure also produced specific chemical profiles when tested on gunshot residues from different manufacturers. Overall, this thesis represents the development of a rapid and reproducible procedure capable of simultaneously detecting the widest possible range of components present in organic gunshot residue.
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Baldia, Christel M. "Development of a protocol to detect and classify colorants in archaeological textiles and its application to selected prehistoric textiles from Seip Mound in Ohio." Connect to resource, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1122567876.
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Ducay, Rey Nann Mark Abaque. "Direct Detection of Aggregates in Turbid Colloidal Suspensions." Miami University / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=miami1439434385.
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Zhu, Zhengjiang. "Mass spectrometric analysis of monolayer protected nanoparticles." 2012. https://scholarworks.umass.edu/dissertations/AAI3498415.
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Monolayer protected nanoparticles (NPs) include an inorganic core and a monolayer of organic ligands. The wide variety of core materials and the tunable surface monolayers make NPs promising materials for numerous applications. Concerns related to unforeseen human health and environmental impacts of NPs have also been raised. In this thesis, new analytical methods based on mass spectrometry are developed to understand the fate, transport, and biodistributions of NPs in the complex biological systems. A laser desorption/ionization mass spectrometry (LDI-MS) method has been developed to characterize the monolayers on NP surface. LDI-MS allows multiple NPs taken up by cells to be measured and quantified in a multiplexed fashion. The correlations between surface properties of NPs and cellular uptake have also been explored. LDI-MS is further coupled with inductively coupled plasma mass spectrometry (ICP-MS) to quantitatively measure monolayer stability of gold NPs (AuNPs) and quantum dots (QDs), respectively, in live cells. This label-free approach allows correlating monolayer structure and particle size with NP stability in various cellular environments. Finally, uptake, distribution, accumulation, and excretion of NPs in higher order organisms, such as fish and plants, have been investigated to understand the environmental impact of nanomaterials. The results indicate that surface chemistry is a primary determinant. NPs with hydrophilic surfaces are substantially less toxic and present a lower degree of bioaccumulation, making these nanomaterials attractive for sustainable nanotechnology.
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Menard, Laurent D. "Structure and dynamics in ligand-protected and supported metal nanoparticles /." 2006. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3250290.
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Thesis (Ph. D.)--University of Illinois at Urbana-Champaign, 2006.<br>Source: Dissertation Abstracts International, Volume: 68-02, Section: B, page: 0939. Adviser: Ralph G. Nuzzo. Includes bibliographical references. Available on microfilm from Pro Quest Information and Learning.
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Durocher, Adrianna U. K. "Examining the interrelationship between the opioid epidemic, public health, and forensic science." Thesis, 2020. https://hdl.handle.net/2144/42141.
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The United States (U.S.) government has been attempting to combat the growing opioid epidemic ravaging the nation. The opioid epidemic has had a significant impact on public health and forensic science laboratories. Moreover, this epidemic has moderate to fatal health consequences for expectant mothers with substance use disorder and their child who may develop Neonatal Abstinence Syndrome (NAS), otherwise known as Neonatal Opioid Withdrawal Syndrome (NOWS). The objective of this thesis is to emphasize that further research is needed for the identification and quantification of opioids in human breast milk. This topic has public health implications such as discussing the information gaps as it relates to a highly vulnerable group, women, and infants, affected by the opioid epidemic. Furthermore, there are implications in forensic science connected to postmortem toxicology and pathology when determining the cause of death and contributing factors in pediatric cases. This emphasis on the need for greater research will be accomplished by highlighting the opioid epidemic, its impact and further understanding of the addictive drug class known as opioids. The history of the crisis, effects on society as well as pharmaceutical knowledge of opioids will assist in development of plans to suppress growth and provide care for the afflicted. Furthermore, this thesis will attempt to demonstrate the need for further research involving opioids will be of significant value for public health and forensic science. As the forensic laboratories and various medical facilities are at the forefront of the opioid epidemic, there is a need for more robust, validated, inexpensive, and fast drug detection methodologies. Increasing rates of new designer drugs, addiction, and opioid-related deaths has caused a backlog in the forensic laboratories due to the great number of cases. While, the higher instances of maternal substance use disorder (SUD)/ opioid use disorder (OUD) with parallel increases in cases of NAS incidences are a few of the issues that need to be managed by public health leaders. Additionally, this thesis will examine current methodologies for drug quantification of opioids in human breast milk. The valid methodologies developed as well as the findings by the few available studies allowed for the current recommendations related to the acceptability of mothers in MAT programs, using methadone and buprenorphine during pregnancy and postpartum, being able to breastfeed their infant. By examining these studies and the findings, standardization criteria for the development of study designs for new methodologies relating to drug determination in human breast milk could be developed. The establishment of standardization criteria and acknowledging information gaps in current knowledge will be significant as these findings could influence policies, guidelines and procedures relating to maternal SUD/OUD, NAS/NOWS, and pediatric death determination as well as postmortem toxicology.
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(8098115), Thakshila Liyanage. "NANOPLASMONIC EFFICACY OF GOLD TRIANGULAR NANOPRISMS IN MEASUREMENT SCIENCE: APPLICATIONS RANGING FROM BIOMEDICAL TO FORENSIC SCIENCES." Thesis, 2019.
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<p>Noble metal nanostructures display collective
oscillation of the surface conduction electrons upon light irradiation as a
form of localized surface plasmon resonance (LSPR) properties. Size, shape and
the refractive index of surrounding environment are the key features that
controls the LSPR properties. Surface passivating ligands have the ability to
modify the charge density of nanostructures to allow resonant wavelength to
match that of the incident light, a phenomenon called “plasmoelectric effect,”.
According to the drude model Red and blue shifts of LSPR peak of nanostructures
are observed in the event of reducing and increasing charge density,
respectively. However, herein we report unusual LSPR properties of gold triangular
nanoprisms (Au TNPs) upon functionalization with para-substituted thiophenols
(X-Ph-SH, X = -NH<sub>2</sub>, -OCH<sub>3</sub>, -CH<sub>3</sub>, -H, -Cl, -CF<sub>3</sub>,
and -NO<sub>2</sub>). Accordingly, we hypothesized that an appropriate energy
level alignment between the Au Fermi energy and the HOMO or LUMO of ligands
allows delocalization of surface plasmon excitation at the hybrid
inorganic-organic interface, and thus provides a thermodynamically driven
plasmoelectric effect. We further validated our hypothesis by calculating the
HOMO and LUMO levels and also work function changes of Au TNPs upon
functionalization with para substituted thiol. We further utilized our unique
finding to design ultrasensitive plasmonic substrate for biosensing of cancer
microRNA in bladder cancer and owe to unpresidential sensitivity of the
developed Au TNPs based LSPR sensor, for the first time we have been utilized
to analysis the tumor suppressor microRNA for more accurate diagnosis of BC.
Additionally, we have been advancing our sensing platform to mitigate the false
positive and negative responses of the sensing platform using surface enhanced
fluorescence technique. This noninvasive, highly sensitive,
highly specific, also does not have false positives technique provide strong
key to detect cancer at very early stage, hence increase the cancer survival
rate. Moreover, the electromagnetic
field enhancement of Surface-Enhanced Raman Scattering (SERS) and other related
surface-enhanced spectroscopic processes resulted from the LSPR property. This
dissertation describes the design and development of entirely
new SERS nanosensors using flexible SERS substrate based on unique LSPR
property of Au TNPs and developed sensors shows excellent SERS activity
(enhancement factor = ~6.0 x 106) and limit of detection (as low as 56
parts-per-quadrillions) with high selectivity by chemometric analyses among
three commonly used explosives (TNT, RDX, and PETN). Further we achieved the
programable self-assembly of Au TNPs using molecular tailoring to form a 3D
supper lattice array based on the substrate effect. Here we achieved the
highest reported sensitivity for potent drug analysis, including opioids and
synthetic cannabinoids from human plasma obtained from the emergency room. This
exquisite sensitivity is mainly due to the two reasons, including molecular
resonance of the adsorbate molecules and the plasmonic coupling among the
nanoparticles. Altogether we are highly optimistic that our research will not
only increase the patient survival rate through early detection of cancer but
also help to battle the “war against drugs” that together is expected to
enhance the quality of human life. </p>
<p> </p>
28
Pruckler, Rachel. "An assessment of pipette calibration stability using statistical process control charts." Thesis, 2016. https://hdl.handle.net/2144/19479.
Full textAbstract:
Routine pipette calibration is an essential part of any quality assurance and quality control program in the forensic sciences and beyond. Pipette calibration standards in a forensic laboratory are typically set to the limits outlined by the document ISO8655, published by the International Organization for Standardization for the general scientific community. Alternative methods exist that may be capable of monitoring pipette stability across time in a forensic setting. Statistical process control charts, or Shewhart charts, are one such form of process control, which is being investigated for its potential application to pipette calibration monitoring for forensic DNA laboratories. Indeed, the application of process control lines for monitoring the calibration of volumetric equipment is not without precedent.1
To investigate the applicability of process control charts for monitoring pipette stability, a series of X ̅ and S charts, a type of Shewhart chart, have been produced from eight years of collected calibration data. A total of 71 pipettes of the following sizes were examined: 1-10 µL, 1-10 µL multi-channel, 10-100 µL, 100-1000 µL, 1-3 µL, 30-300 µL, 5-50 µL, 5-50 µL multi-channel, and 500-5000 µL pipettes. The ISO8655 calibration recommended volume limits of these pipettes have been added to the charts for the purposes of comparison. With these charts, it is possible to assess pipette performance over time in comparison to the ISO8655 calibration standards and to the control limits imposed by the Shewhart charts. The completed charts suggest that the methodology proposed by Shewhart shows promise as a supplement to ISO8655 recommendations for monitoring pipette stability across time.
To corroborate the value of using Shewhart charts to monitor pipette performance, a serial dilution study in conjunction with a series of simulations with dynamic modeling software was performed. This dilution study investigated whether the systematic biases shown by the Shewhart charts could be measured in a laboratory setting. The simulations investigated multiple hypothetical pipetting scenarios concerning various levels of systematic bias. The simulations consistently corroborated the value of Shewhart charts to enforce better compliance between a pipette’s nominal and actual volume delivery, while the serial dilution study offered partial evidence of systematic pipetting bias.
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Denman, John A. "The application of time-of-flight secondary ion mass spectrometry (ToF-SIMS) to forensic glass analysis and questioned document examination." 2007. http://arrow.unisa.edu.au:8081/1959.8/40576.
Full textAbstract:
The combination of analytical sensitivity and selectivity provided by time-of-flight secondary ion mass spectrometry (ToF-SIMS), with advanced statistical interrogation by principal component analysis (PCA), has allowed a significant advancement in the forensic discrimination of pen, pencil and glass materials based on trace characterisation.
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(10701216), Ashur Scott Rael. "Advances in gas chromatography, thermolysis, mass spectrometry, and vacuum ultraviolet spectrometry." Thesis, 2021.
Find full textAbstract:
In the area of forensic chemistry, improved or new analysis methods are continually being investigated. One common and powerful technique used in forensic chemistry is wall-coated open-tubular column (WCOT) gas chromatography with electron ionization single quadrupole mass spectrometry (GC-MS). Improvements to and effectiveness of alternatives to this instrumental platform were explored in an array of parallel inquiries. The areas studied included the column for the chromatographic separation, the universal detection method employed, and the fragmentation method used to enhance molecular identification. <br><br>Superfine-micropacked capillary (SFµPC) columns may provide an alternative to commercial packed GC columns and WCOT GC columns that combines the benefits of the larger sample capacity of packed columns and the benefits of the excellent separation capabilities and mass spectrometry (MS) flow rate compatibility of WCOT columns. SFµPC columns suffer from high inlet pressure requirements and prior reported work has required specialized instrumentation for their use. Fabrication of and chromatography with SFµPC GC columns was successfully achieved with typical GC-MS instrumentation and within the flow rate limit of a MS. Additionally, the use of higher viscosity carrier gasses was demonstrated to reduce the required inlet pressure for SFµPC GC columns.<br><br>Recently, a new vacuum ultraviolet spectrometer (VUV) universal detector has been commercialized for GC. The ability of VUV detectors to acquire absorbance spectra from 125 nm to 430 nm poses a potential alternative to MS. As such, GC-VUV provides an exciting potential alternative approach to achieving excellent quantitative and qualitative analysis across a wide range of analytes. The performance of VUV and MS detectors for forensic analysis in terms of quantitative and qualitative analysis was compared. Analysis of alkylbenzenes in ignitable liquids was explored, which can be important evidence from suspected arson fires and are difficult to differentiate with MS. The VUV detector was found to have superior specificity and comparable sensitivity to the MS detector in scan mode.<br><br>Addition of thermolysis (Th) as an orthogonal fragmentation pathway provides the opportunity to increase the differences between MS fragmentation patterns. Fragmentation has been widely established to aid in identification of molecules with MS by providing characteristic fragments at characteristic relative abundances. However, molecules with very similar structures do not result in sizable spectral differences in all cases with typical MS fragmentation techniques. A series of Th units were fabricated and integrated into GC-Th-MS instruments. Th-MS was conducted with the thermally labile nitrate esters across a range of instrumentation and thermal conditions.<br>
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Lauzon, Nidia. "Imagerie moléculaire d’empreintes digitales par spectrométrie de masse : potentiels et applications en science forensique." Thèse, 2018. http://hdl.handle.net/1866/21579.
Full text
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(9708611), Zackery Ray Roberson. "Advances in Gas Chromatography and Vacuum UV Spectroscopy: Applications to Fire Debris Analysis & Drugs of Abuse." Thesis, 2021.
Find full textAbstract:
In forensic chemistry, a quicker and more accurate analysis of a sample is always being pursued. Speedy analyses allow the analyst to provide quick turn-around times and potentially decrease back-logs that are known to be a problem in the field. Accurate analyses are paramount with the futures and lives of the accused potentially on the line. One of the most common methods of analysis in forensic chemistry laboratories is gas chromatography, chosen for the relative speed and efficiency afforded by this method. Two major routes were attempted to further improve on gas chromatography applications in forensic chemistry.<br> The first route was to decrease separation times for analysis of ignitable liquid residues by using micro-bore wall coated open-tubular columns. Micro-bore columns are much shorter and have higher separation efficiencies than the standard columns used in forensic chemistry, allowing for faster analysis times while maintaining the expected peak separation. Typical separation times for fire debris samples are between thirty minutes and one hour, the micro-bore columns were able to achieve equivalent performance in three minutes. The reduction in analysis time was demonstrated by analysis of ignitable liquid residues from simulated fire debris exemplars.<br> The second route looked at a relatively new detector for gas chromatography known as a vacuum ultraviolet (VUV) spectrophotometer. The VUV detector uses traditional UV and far-ultraviolet light to probe the pi and sigma bonds of the gas phase analytes as well as Rydberg traditions to produce spectra that are nearly unique to a compound. Thus far, the only spectra that were not discernable were from enantiomers, otherwise even diastereomers have been differentiated. The specificity attained with the VUV detector has achieved differentiation of compounds that mass spectrometry, the most common detection method for chromatography in forensic chemistry labs, has difficulty distinguishing. This specificity has been demonstrated herein by analyzing various classes of drugs of abuse and applicability to “real world” samples has been demonstrated by analysis of de-identified seized samples.<br>