Dissertations / Theses: 'Forensic chemistry'

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Salem, Roberta Sue. "Developing a one-semester course in forensic chemical science for university undergraduates." Diss., Manhattan, Kan. : Kansas State University, 2009. http://hdl.handle.net/2097/1333.

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Keen, Imelda P. "Forensic applications of Raman microprobe spectroscopy." Thesis, Queensland University of Technology, 1998.

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Khattab, Amin Khalid. "Fabrication, functionalization and characterization of silica monolith for forensic chemistry applications." Thesis, University of Hull, 2014. http://hydra.hull.ac.uk/resources/hull:10112.

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The physiochemical properties of silica monolith make it an ideal base material for drugs extracting, pre-concentrating and separation from biological samples which can interact not only with molecules but also with ions and atoms. However, the fabrication of silica monoliths still has some problems, such as cost, limited capacity and fabrication and modification methodology, which can be time consuming and labour intensive. Structure evolution of silica monolith was studied in microwave and conventionally processed samples over the temperature range from 25 to 70 oC. The samples were produced using sol-gel processing. The microwave process was performed using a single mode cavity at 2.45GHz. Characterization of produced silica monoliths were carried out using a variety of techniques, including Scanning Electron Microscopy (SEM) analysis, EDX analysis, BET and BJH analysis. The data obtained showed that structural differences do exist between conventional and microwave processed samples. It was found however, that microwave based fabrication offered a significantly quicker (11 min) gelation process, compared to those obtained using the thermal heated oven methodology (4,320 min). The silica monolithic surfaces were modified with three different phases C₁₈, gold nanoparticles and graphene which received a thermal treatment at different programmed powers in two different ovens, conventional and microwave. Three substantial variance were also identified from the structural characterization of modified silica surfaces processed using microwave heating and conventional heating methods: 1- The use of microwave heating during C₁₈ surface modification improved not only the attachment of C₁₈ groups to the silica surface but also increased the extraction efficiency of caffeine and eserine from standard solutions (102 % and 97 %, respectively). 2- The fabrication of gold nanoparticles-NH2-silica monolith using microwave heating was found to improve the sensitivity and selectivity of modified silica surface and make possible to extract, detect and quantify more than one type of drugs of abuse at the same time within few minutes. 3- Using graphene-silica monolith makes the extraction of non-polar, polar, very polar and water-soluble analytes, based on both hydrophobic and electronic interactions, easy and simple. Fabrication and modification of silica monoliths using microwave heating make the sol-gel procedure much faster and easier and allow for non-polar, polar, very polar and water-soluble analytes to be extracted more efficiently to produce accurate and precise results compared to the conventional method for fabrication and modification of silica monoliths using three phases (C₁₈, gold nanoparticles and graphene). Finally, this technique make the modified silica monolithic column capable to extract selected drugs of abuse from biological samples and produce qualitative and quantitative results at the same time using chemiluminescence based immunoassays or HPLC-UV.

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Baize, John. "Forensic Soil Analysis: Characterization of the Sand Fraction." TopSCHOLAR®, 1997. http://digitalcommons.wku.edu/theses/767.

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The purpose of this project was to develop a comprehensive analytical method for the characterization of soil by examining particle size, elemental composition, and percent organic matter in soil, and to determine its forensic applicability. In this study, five soils of varying geological locations were examined including two samples from Kentucky; two samples from Pennsylvania; and one from Washington D C A Gilson sonic sieve shaker was used to separate fractions of soil to determine particle size, and a JEOL scanning electron microscope with a Kevex EDS detector was used to determine elemental composition. These techniques coupled with percent total carbon analysis (determined with a LECO CHN-1000) provide a method that measures three forensic properties instead of one for the forensic comparison of soil.

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Andrews, Anthony Robert John. "The chemiluminescence detemination of drugs of forensic interest." Thesis, University of Hull, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.306129.

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Buttigieg, Gavin. "Forensic and toxicological applications of atomic analysis." Diss., The University of Arizona, 2003. http://hdl.handle.net/10150/280402.

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Toxicological and forensic applications of analytical chemistry provide both interesting and unique opportunities for analytical chemists to hone their skills and push their abilities. Modern analytical chemistry has afforded researchers the ability to probe into the intricate pathways of biochemical processes by systematic identification and characterization of biologically relevant compounds. Unfortunately, often due to the restrictive specifications of the instrumentation used, it is necessary to remove those compounds from their natural environments such that their structure and at the very least the significance of those compounds may not be fully recognized. The work described herein identifies and characterizes two biologically relevant arsenic and selenium containing species. These species were synthesized and identified in environments that are very similar to those found in vivo. The use of chemical information contained within a small arms cartridge has seen extremely limited use by forensic laboratories despite the wealth of chemical information that may be useful in differentiating between cartridges of various manufacturers. The study herein uses the elemental composition of small arms rifle primers to develop a multivariate model against which unknown primers were compared and ultimately classified. The FBI's practice of elemental analysis of small arms projectiles has recently come under fire as the result of an ex-FBI metallurgist's research study which concluded that the trace elements analyzed were too rigidly controlled by Pb smelters and therefore not useful in distinguishing between batches of ammunition. The scientific community is now scrutinizing the practice with a National Academy of Science review of the FBI's practices. Unlike the trace elements utilized by the FBI for distinguishing between projectiles of various "origins" Pb isotopic signature is not controlled by smelters and should, even in the case of recycled Pb, vary when Pb from differing origins is utilized for the manufacture of small arms projectiles. The study described herein shows that Pb isotopic analysis of small arms projectiles from various regions of the world is useful for differentiating between small arms projectiles and in limited cases may even be useful in determining the geographic origin of projectile manufacture.

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Peterson, Kristina L. "Advances in flow extraction techniques : applications in forensic toxicology /." Thesis, Connect to this title online; UW restricted, 1997. http://hdl.handle.net/1773/11552.

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Bani, Rashaid Ayat H. "Clinical and Forensic Biomarkers in Human Hair." Ohio University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1407256298.

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Connon, Catherine Cupples. "Improving Processing Efficiency for Forensic DNA Samples." Thesis, University of North Texas, 2015. https://digital.library.unt.edu/ark:/67531/metadc799515/.

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The goal of this project was to reduce processing time for forensic DNA testing without incurring significant added costs and/or the need for new instrumentation, while still generating high quality profiles. This was accomplished by: 1) extraction normalization using the ChargeSwitch® Forensic DNA Purification Kit such that a small range of DNA concentrations was consistently obtained, eliminating the need for sample quantification and dilution; 2) developing fast PCR protocols for STR primer sets using shorter amplification methods, low volume reactions and non-fast thermal cyclers; and 3) developing a quicker 3130xl Genetic Analyzer detection method using an alternative polymer/array length combination. Extraction normalization was achieved through a reduction in bead quantity, thereby forcing an increase in bead binding efficiency. Four products (AmpliTaq Gold® Fast PCR Master Mix, KAPA2G™ Fast Multiplex PCR Kit, SpeedSTAR™ HS DNA Polymerase and Type-it Microsatellite PCR Kit) were evaluated for low volume (3μl) fast PCR on a 384-well Veriti® thermal cycler with the Identifiler primer set. KAPA2G™ was selected for 3μl fast PCR protocols using PowerPlex 16 HS and Identifiler Plus primer sets (42-51min), as well as 5μl and 6μl Identifiler fast reactions on a 9700 thermal cycler (51-60min). Alternative detection (POP-6™/22cm) achieved 24-28min run times, but with decreased resolution as compared to traditional POP-4®/36cm detection for alleles >200bp; however, 1bp resolution was still obtainable for alleles <300bp. These modifications resulted in robust databasing processes with up to a 37% reduction in processing time for buccal swabs and Buccal DNA Collectors™ using the three primer sets evaluated (3μl fast PCR reactions) and generated high quality STR profiles with ≥90% pass rates.

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Adams, Deidré Ilana. "The development of appropriate methods for drug analysis at the Forensic Chemistry Laboratory, Cape Town." Master's thesis, University of Cape Town, 2008. http://hdl.handle.net/11427/6294.

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Includes abstract.
Includes bibliographical references (leaves 85-92).
The Forensic Chemistry Laboratory, Cape Town, analyses samples submitted by forensic pathologists in order to assist with determining the cause of death in cases of unnatural death. Many of these samples test positive for the presence of drugs and other toxic substances. Because of resource constraints, pathologists submit samples at their discretion and not on a routine basis. In this study, forensic and chemical aspects were combined and used as the motivation for the development of an improved extraction procedure for systematic toxicological analysis. The scope of the study was therefore twofold. Firstly, a study was undertaken of unnatural deaths in the greater Cape Town area for which samples would not normally have been submitted.

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Kashkary, Loay M. T. "Development of a combined DNA and drug extraction methodology for forensic toxicology application." Thesis, University of Hull, 2014. http://hydra.hull.ac.uk/resources/hull:11661.

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Biological samples recovered at crime scenes may contain unsuspected and valuable evidence, such as illicit drugs, in addition to nucleic acids. Deoxyribonucleic acid (DNA) analysis provides valuable information to identify a suspect or victim, as well as to exclude an innocent individual as the perpetrator of a crime. Identification of drugs can also be very informative for forensic investigation to determine whether a perpetrator committed a crime under the influence of illicit substances. In the field of forensic analysis, sample preparation for identifying both DNA and drugs of abuse represents a challenge due to limited sample quantity and only trace levels of target analytes present in the matrices. As a result, an analytical approach has been developed to enable the combined extraction of DNA and four amphetamines (amphetamine [AM], methamphetamine [MA], 3,4-methylenedioxyamphetamine [MDA], and 3,4-methylenedioxymethamphetamine hydrochloride [MDMA]) from a small amount of sample (50 μl) using a single extraction procedure. This study has focused on solid-phase extraction (SPE) using inorganic silica-based matrices as sorbents to facilitate such sample processing. The advantages of using inorganic silica-based monoliths are due to the simple fixation of the material in a column or within a microfluidic device, their mechanical stability with organic solvents, the availability of simple surface modifications to enable the desired chemical interaction with the target molecules, and a unique bimodal structure that allows a large surface area with minimum back pressure. A dual-phase SPE method was developed consisting of silica beads modified with octadecyl groups packed inside a luer lock adapter for amphetamine extraction coupled in series with a silica-based monolith for DNA extraction within a microfluidic system for a fully combined genetic and drug extraction system. The proposed method was effective for the extraction of the target drugs from a spiked buffer and artificial urine giving an average recovery greater than 70% and 50%, respectively, with high reproducibility (˂ 15% RSD). The limits of detection were 0.6 μg ml⁻¹ for AM and MA, 0.7 μg ml⁻¹ for MDA, and 0.8 μg ml⁻¹ for MDMA with linear calibration curves between 0.625 and 20 μg ml⁻¹. The method was also able to extract DNA from the spiked TE buffer and urine sample with average extraction efficiencies of 36% and 30%, respectively, which were successfully amplified via the polymerase chain reaction (PCR). The proposed method is not only suitable for the combined extraction of DNA and amphetamines from a limited sample size, but also reduces sample handling and potential contamination. This method could, in future, be applied to anti-doping analysis for the detection of doping agents and conducting DNA profiling as evidence to ascertain whether samples belong to the right athletes.

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Huynh, Vivian. "Forensic Analysis of Ink on Documents Using Direct Analyte-Probed Nanoextraction Coupled Techniques." Thesis, University of North Texas, 2016. https://digital.library.unt.edu/ark:/67531/metadc849635/.

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Analzying questioned documents in a nondestructive nature has been an issue for the forensic science community. Using nondestructive techniques such as video spectral comparator does not give reliable information due to the variations in gray or color levels that are distinguished differently by analysts. Destructive techniques such as chromatography give dependable, qualitative and quantitative, information but involves altering the evidentiary value of these questioned documents. The paradox of document examination becomes a problem when document evidence is involved, especially when trying to preserve its evidentiary value and critical data is needed. Thus, a nondestructive technique has been developed to solve the loopholes in document examinations. Direct analyte-probed nanoextraction (DAPNe) is a nanomanipulation technique that extracts ink directly off the document for further examination. A watermark is left, at most, post-extraction. DAPNe utilizes a tip emitter, pre-filled with a solvent, which is controlled in x-, y-, and z-coordinates via joystick controller and aspirates/extracts using a pressure injector. The versatility of this technique lies within the solvent chemistry and its capability to be coupled to various types of instrumentation. The extraction solvent can be altered to target specific components in the ink. For example, a chelator may be added to target metal ions found in ancient inks or methanol may be added to target certain organic resins and binding agents found in modern inks. In this study, DAPNe has been coupled to nanospray ionization mass spectrometry, fluorescence microscopy, Raman spectroscopy, matrix-assisted laser desorption ionization mass spectrometry, and laser ablation to solve questioned document concerns in the area of falsified or forged documents, redacted documents, and aging studies.

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Cai, Yue. "Nondestructive multi-element analysis of colorants for forensic applications and artwork authentication." HKBU Institutional Repository, 2013. https://repository.hkbu.edu.hk/etd_ra/1528.

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Muro, Claire K. "Further Development of Raman Spectroscopy for Body Fluid Investigation| Forensic Identification, Limit of Detection, and Donor Characterization." Thesis, State University of New York at Albany, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10275358.

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The challenges to forensic body fluid analysis have placed limitations on the type of information that investigators can acquire and how that information can be collected. In recent years, Raman spectroscopy has proven itself useful for characterizing body fluids. In 2008, a large-scale investigation was undertaken to explore the use of Raman spectroscopy as a means of identifying body fluids. This work resulted in multidimensional Raman spectroscopic signatures for the five main body fluids: semen, peripheral blood, saliva, vaginal fluid, and sweat. These studies were incredibly successful and created the foundation for years of continued research. Accordingly, the studies included in this thesis have been specifically chosen to frame the previous research projects. They include a suite of projects aimed to advance and validate the developed method.

First, a statistical model was developed to automatically identify and differentiate body fluids based on their Raman spectra. The multidimensional spectroscopic signatures mentioned above are very effective at identification, but they are body fluid-specific. In other words, they individually evaluate whether or not an unknown spectrum is from a particular body fluid, such as blood. Additionally, each signature was built on spectra from a limited number of donors. To improve on this capability, a single classification model was built on the Raman spectra from 60 donors (12 for each body fluid). This model was externally validated with an additional 15 donors in order to objectively assess the model’s performance. All of the external validation donors were correctly identified, illustrating how accurate and robust the model is.

Second, the limit of detection (LOD) for the classification model was explored as a form of validation. It is vitally important that a method’s limits be established before deploying it into use. The LOD of peripheral blood was investigated. Peripheral blood is unique from other body fluids because its Raman spectrum has been attributed almost entirely to one molecule- hemoglobin. Because hemoglobin is only found in red blood cells (RBCs), the Raman spectrum of peripheral blood essentially results purely from RBCs. Given this, we chose to start with a single RBC, and then increase the volume until identification was successful. We found that we were able to conclusively and confidently identify peripheral blood using a single red blood cell. This limit is 5000X smaller than the amount of blood required for DNA analysis, demonstrating the sensitivity of the developed method.

Finally, the method was further advanced by incorporating donor characterization into the process. Besides identifying body fluids, the method can now extract “phenotypic” information about the donor. Raman spectroscopy and multivariate data analysis were used to determine the biological sex of saliva donors, and the race of semen donors. These studies will help forensic investigators extract incredibly useful information about a potential suspect or victim, and can be performed directly at a crime scene for instant results.

Altogether, these studies combine to strengthen the method previously developed by our research group. More importantly, they help to bridge the gap between research and application. Creating a universal method to differentiate and identify body fluids, investigating the method’s LOD, and developing additional techniques to characterize body fluids represents a significant contribution to the field of forensic chemistry. The universal method created within this thesis will be adapted to perform on-site analysis of physical evidence at crime scenes. The methods’ incredible sensitivity has been demonstrated by determining that it can identify peripheral blood based on a single RBC. Finally, by developing models to characterize body fluid donors, investigators will be able to extract useful information about individuals that may have been present at a crime scene. Additional studies are already being conducted to make further improvements, and our method is poised to make a significant contribution to the field of crime scene investigation.

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Eltayeb, M. A.-Z. "Aspects of the detection and determination of aromatic nitro-compounds for forensic purposes." Thesis, Queen's University Belfast, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.374190.

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Besen, Lucas Riboli. "Entre laudos, compostos químicos e máquinas : saberes e práticas a partir do Setor Técnico-Científico da Superintendência Regional do Departamento de Polícia Federal de Rio Grande do Sul." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2014. http://hdl.handle.net/10183/114565.

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Esta dissertação tem como temática a relação entre a Antropologia do Direito e os Estudos Sociais da Ciência e da Tecnologia no que tange a produção de laudos periciais por peritos criminais federais. Tendo o Grupo de Perícias de Laboratório do Setor Técnico-Científico da Superintendência Regional do Departamento de Polícia Federal de Porto Alegre como local privilegiado de observação, busca-se problematizar as relações entre ciência e direito assim como compreender, através do acompanhamento dos peritos criminais federais na sua atividade cotidiana, como atores e organizações mobilizam, justapõem e mantêm unidos os elementos para constituir, ao fim, um laudo pericial. Nesse sentido, parte-se da perspectiva de que as esferas do direito e da ciência não estão separadas, mas são coproduzidas. Logo, procura-se potencializar os laudos periciais através da descrição da rede que envolve a sua produção. Parte-se da hipótese de que os laudos não são apenas um processo de purificação, mas a complexificação de uma rede que, ao final, resulta em um ator pontualizado, sendo que este performatiza um ordenamento da realidade condizente com uma ontologia política específica. Acredita-se que, através dessa pesquisa, poder-se-á complexificar as discussões já alçadas pela Antropologia Brasileira sobre a produção de justiça e de ciência, assim como alimentar o debate político sobre os limites e as potencialidades dos usos de provas científicas nos tribunais brasileiros.
This dissertation is about the relation between the Anthropology of Law and Rights studies and the Social Studies of Science and Technology regarding the production of forensic reports by federal forensic investigators. Having the Forensic Laboratory of the Techno-scientific Bureau of the Regional Superintendence of the Federal Police Department (SETEC/SR/DPF) at Porto Alegre city as a privileged observation site, I seek to discuss the relationship between the science and the law as well as to complexify, while observing the everyday tasks of the forensic investigators, how actors and organizations mobilize, juxtapose and keep together the elements that will constitute, after all, a forensic report. That being said, it is assumed from the start that law and science are not separated instances, but are coproduced. Therefore, I seek to potentiate the forensic reports through the description of the network that enables their production. I start with the hypothesis that the reports are not only a process of purification, but the complexification of a network that, by the end of the process, results in a punctualised actor that performs an ordering of reality aligned with a specific ontological politic. It is believed that, through this research, it will be possible to complexify the discussions raised by Brazilian Anthropology about the production of justice and science and to nurture the political debate about the limitations and potentialities of the usage of scientific evidence in Brazilian courts.

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Meyers, Lisa A. "Investigations of Nuclear Forensic Signatures in Uranium Bearing Materials." University of Cincinnati / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1380556939.

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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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Muccio, Zeland. "Isotope ratio mass spectrometry a rapidly developing tool for forensic samples /." Ohio : Ohio University, 2010. http://www.ohiolink.edu/etd/view.cgi?ohiou1263488205.

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Swortwood, Madeleine Jean. "Comprehensive Forensic Toxicological Analysis of Designer Drugs." FIU Digital Commons, 2013. http://digitalcommons.fiu.edu/etd/997.

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New designer drugs are constantly emerging onto the illicit drug market and it is often difficult to validate and maintain comprehensive analytical methods for accurate detection of these compounds. Generally, toxicology laboratories utilize a screening method, such as immunoassay, for the presumptive identification of drugs of abuse. When a positive result occurs, confirmatory methods, such as gas chromatography (GC) or liquid chromatography (LC) coupled with mass spectrometry (MS), are required for more sensitive and specific analyses. In recent years, the need to study the activities of these compounds in screening assays as well as to develop confirmatory techniques to detect them in biological specimens has been recognized. Severe intoxications and fatalities have been encountered with emerging designer drugs, presenting analytical challenges for detection and identification of such novel compounds. The first major task of this research was to evaluate the performance of commercially available immunoassays to determine if designer drugs were cross-reactive. The second major task was to develop and validate a confirmatory method, using LC-MS, to identify and quantify these designer drugs in biological specimens. Cross-reactivity towards the cathinone derivatives was found to be minimal. Several other phenethylamines demonstrated cross-reactivity at low concentrations, but results were consistent with those published by the assay manufacturer or as reported in the literature. Current immunoassay-based screening methods may not be ideal for presumptively identifying most designer drugs, including the “bath salts.” For this reason, an LC-MS based confirmatory method was developed for 32 compounds, including eight cathinone derivatives, with limits of quantification in the range of 1-10 ng/mL. The method was fully validated for selectivity, matrix effects, stability, recovery, precision, and accuracy. In order to compare the screening and confirmatory techniques, several human specimens were analyzed to demonstrate the importance of using a specific analytical method, such as LC-MS, to detect designer drugs in serum as immunoassays lack cross-reactivity with the novel compounds. Overall, minimal cross-reactivity was observed, highlighting the conclusion that these presumptive screens cannot detect many of the designer drugs and that a confirmatory technique, such as the LC-MS, is required for the comprehensive forensic toxicological analysis of designer drugs.

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Uchimoto, Mari L. "Developing a microRNA body fluid identification test for use in forensic casework." Thesis, University of Huddersfield, 2014. http://eprints.hud.ac.uk/id/eprint/24470/.

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Body fluid identification (BFID) forms a crucial aspect within forensic investigations. BFID is particularly important where the origin of a DNA profile is also needed e.g. sexual assaults. The aim of this work was to develop a RNA-based BFID for use in forensic casework. The test was developed in three stages: exploring co-isolation and single isolation strategies, screening and selecting RNA markers and different casework conditions e.g. low-level, non-human, degraded and mixed samples. Blood, saliva, skin, semen and vaginal material samples were collected. Samples underwent single or co-isolation (DNA, total RNA or messenger RNA), DNA quantification, cDNA synthesis and qPCR using a number of different candidate markers and reference genes for microRNA (miRNA) and messenger RNA. During the development of the test the following novel findings were observed: utilisation of complex co-isolation methods was not need for co-analysis of RNA and DNA; six highly discriminative miRNA markers were identified for miRNA analysis: blood (miR-451 and miR-194); saliva (miR-205); vaginal material (miR-224 and miR-335) and semen (miR-891a). In terms of casework applications, microRNA analysis showed potential for greater sensitivity than current enzymatic methods with the use of appropriate reference gene; species specificity was observed for reference gene RNU44; sample stability was observed in 1-yr bloodstains with miR-451 and RNU44 and successful resolution of major and minor components was achieved.

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Lee, Emma-Jane. "Forensic sample analysis using supercritical fluid extraction coupled with solid phase microextraction." Thesis, University of South Wales, 2007. https://pure.southwales.ac.uk/en/studentthesis/forensic-sample-analysis-using-supercritical-fluid-extraction-coupled-with-solid-phase-microextraction(0159ef22-bb14-433f-a50f-2bd2773ef937).html.

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A third of adults in the UK admit to using controlled substances at least once hi their lives and the most commonly abused drug was found to be cannabis, followed by the opiates and ecognine derivatives. Forensic laboratories are continually trying to reduce the turnaround time for samples submitted for analysis, to less than the current time of four days. One of the main aims of this work was to reduce the time taken to prepare, extract and analyse hair for target analytes. A new method combining supercritical fluid extraction and solid phase micro-extraction (SFE/SPME) is introduced. This coupled procedure utilises the advantages of using supercritical carbon dioxide as an extraction solvent and collecting the extract on a selected SPME fibre. Together the combined techniques provide a method that is solvent-free and highly selective, whilst reducing sample preparation to a minimum. Digested hair samples are examined by SEM to find the best method. Alkali hydrolysis and enzyme digestion using proteinase K were found to be the most effective pre-extraction methods. Solid hair samples with the addition of a derivatization reagent (BSTFA) gave the best results using the coupled technique. After optimisation and validation, the extraction from both real and spiked samples resulted in recoveries between 60% to 80% for the target analytes A9 -tetrahydrocannabinol (A9- THC) , cannabinol (CBN) and cannabidiol (CBD). Other forensic applications such as the extraction of polycyclic aromatic hydrocarbons and pesticides from environmental and food samples and the examination of fire debris for the presence of accelerants are also carried out. PAH could easily be extracted from complex matrices to give recoveries of up to 97% for some analytes at the optimized conditions of 90°C at 4500 psi over a 10 minute dynamic extraction period. Pesticide extraction gave recoveries of 60 - 80% while the extraction of accelerants from fire debris clearly showed that accelerants such as diesel can be identified over the coincidental PAH and hydrocarbon peaks found in burnt debris. The coupling of SFE to SPME provides an exciting technique that has a wide range of applications and creates potential for a fully automated on-line system.

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Al, Najjar Ahmed Omer. "Enhancement of Sensitivity in Capillary Electrophoresis: Forensic and Pharmaceutical Applications." Ohio University / OhioLINK, 2004. http://www.ohiolink.edu/etd/view.cgi?ohiou1107276943.

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Jäverfalk-Hoyes, Emmy. "Development of Methods in CE, CE-MS and MS/MS : Applications in Pharmaceutical, Biomedical and Forensic sciences." Doctoral thesis, Uppsala University, Department of Medicinal Chemistry, 2001. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-1361.

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Capillary electrophoresis-mass spectrometry has been used successfully for the analysis of a wide range of analytes such as chiral local anaesthetics, sulphonated reactive dyes and endogenous neurotransmitters and neuropeptides.

The partial filling technique was used in CE-MS for chiral separation of bupivacaine and ropivacaine using the non-volatile selector β-cyclodextrin. By only partially filling the capillary with selector and using capillaries coated with polyacrylamide to suppress the electroosmotic flow, introduction of the selector into the mass spectrometer was avoided. An impurity of 0.25% of the R-enantiomer of ropivacaine in the S-form could be detected.

The partial filling technique was developed further using CE employing two different selectors in separate plugs in the capillary. This enhanced the separation efficiency and offered greater flexibility in controlling the separation.

By using transient-isotachophoresis (tITP)-CE-MS it was possible to concentrate and detect classical neurotransmitters and neuropeptides with masses ranging from 104 Da to 1642 Da. γ -Aminopropyltriethoxysilane coated capillaries were used to minimize adsorption of the peptides onto to capillary surface. Endogenous dopamine, glutamate, γ-aminobutyric acid (GABA), acetylcholine, methionine-enkephalin and substance P 1-7 were detected in the striatum of marmoset monkey.

Sulphonated dyes obtained from single textile fibres were analysed using CE-MS. Capillary electrophoresis was found to be a good way of removing the excess amounts of glucose present in the sample that would otherwise interfere with the electrospray ionisation.

Automatic function switching, originally developed for use together with liquid chromatography, was found to be a great method for acquiring MS/MS data when doing infusion experiments saving both time and sample without decreasing the quality of the MS/MS data. It was also found to be a more time efficient way than using the precursor ion scanning mode on the Q-TOF to obtain precursor ion data.

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Walker, Michael John. "Safeguarding food : advances in forensic measurement science and the regulation of allergens, additives and authenticity." Thesis, Kingston University, 2016. http://eprints.kingston.ac.uk/37907/.

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This commentary reports on work published between 2005 and 2015 forming a record of a varied career building technical competence alongside strategic skills in the analytical chemistry and molecular biology of food. The unifying theme is practice based problem solving in the scientific regulation and enforcement of food safety and authenticity. The work demonstrates advances in sound, forensically robust, measurement science addressing problems arising from food additives, food authenticity and food allergens. In particular the mature discipline that underpins the regulation and enforcement of food additives is shown to be needed for the management of food allergens. The background to food regulation and enforcement is described alongside technical appeals in the official food control system to develop societally meaningful food surveillance, supported by a sustainable UK based official food control infrastructure (Public Analyst service) at the interface between science and the law. For food additives, publication of previously un-collated results informs regulatory practice and demonstrates the value of scientific collaboration between both jurisdictions on the island of Ireland. A definitive strategy is reported for the chemical analysis and risk assessment of ‘jelly mini-cups’ in which gel forming additives have caused choking fatalities and solutions to problems in the analysis of two illegal toxic additives, morpholine and dimethyl yellow are described. For food allergens the portfolio includes the first study to assess in quantitative terms the level of risk to peanut allergic consumers in take-away catering, leading to better training and similar work on coeliac disease and the availability of ‘gluten-free’ food. Systematic assessment of food allergen analysis and a programme of analytical improvement to support allergen risk assessment and risk management are discussed. A narrative account of an allergen related food sabotage incident and the subsequent Crown Court case and previously uncollated reports of court-sanctions for allergen noncompliances, severe incidents and deaths make key policy and practice recommendations for improvement in these areas. Page 7 of 162 In the study of food authenticity a critical review describes the nitrogen content of important species in the food supply chain as a proxy in the quantitative estimation of high value flesh foods in compound products. An exemplar study follows determining previously unavailable nitrogen factor data for farmed salmon and salmon frame mince. A critical survey of the up skilling of the UK Official Food Control System in DNA food authenticity techniques and major historical and contemporary reviews of food fraud (butter and horsemeat) support substantial policy and analytical recommendations. Many threats to our food supply can be assessed and managed only with the assistance of measurement science. Integrating elements of chemico-legal practice including lessons learned from ‘referee analyses’ and metrology in chemistry this commentary concludes with a synthesis describing major changes in the UK scientific food control system stemming from the author’s involvement in the ‘Elliott Review’ and recommendations for an international programme of work on food allergen analysis with interconnected learning for the benefit of the analytical and regulatory communities and society at large.

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Stokes, Kathryn Lisa. "Soil-cadaver interactions in a burial environment." University of Western Australia. Faculty of Life and Physical Sciences, 2009. http://theses.library.uwa.edu.au/adt-WU2009.0065.

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Forensic taphonomy is concerned with investigation of graves and grave sites. The primary aim of forensic taphonomy is development of accurate estimations of postmortem interval (PMI) and/or postburial interval (PBI). Soil has previously been largely ignored, therefore this thesis is designed to investigate changes in decomposition as imparted by the soil. Furthermore the impact of cadaver interment on the surrounding soil may offer prospects for identification of clandestine graves. A series of laboratory controlled decomposition experiments using cadavers (Mus musculus) and cadaver analogues (skeletal muscle tissue (SMT); Sus scrofa, Homo sapiens, Ovis aries and Bos Taurus) were designed to investigate decomposition in burial environments. Sequential destructive harvests were carried out to monitor temporal changes during decomposition. Analyses conducted included; mass loss, microbial activity (CO2 respiration) and soil chemistry (pH, EC and extractable NH4 +, NO3 -, PO4 3- and K+). Several experimental variables were tested; frozen-thawed versus refrigerated SMT, different mammalian sources of SMT, different soil type and contribution of soil versus enteric microbial communities. Mass loss measurements for SMT experiments demonstrated a sigmoidal pattern of mass loss, however, larger cadavers (Mus musculus, 5 weeks) did not. The inhumation of SMT (frozen, unfrozen, different mammalian sources) or cadavers leads to an increase in microbial activity (CO2 respiration) within 24 hours of burial. A peak of microbial activity is attained within a week, followed by a decrease and eventual plateau. The rapid influx in microbial activity is matched by corresponding increases in pH and NH4 + concentration. pH and NH4 + are strongly correlated in soils with acidic basal pH, by comparison highly alkaline soil demonstrated no relationship. NH4 + concentration also appeared to be related directly to NO3 - concentration and cadaver or SMT mass. A decrease in NH4 + corresponds with an increase in NO3 -, however, nitrification was unpredictable. Rapid nitrification was observed in sand systems when SMT was interred, but was not noted when cadavers were interred. By comparison both sandy clay loam and loamy sand soils demonstrated rapid nitrification after inhumation of a cadaver. When cadaver or cadaver analogue mass was larger, so were NH4 + and NO3 - concentrations in systems that experienced nitrification.

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Nunes, Pamela Pereira, and 92-98200-8795. "Contextualização e abordagem de conceitos químicos por meio da química forense: uma sequência didática para o Ensino Médio no Ensino da Química." Universidade Federal do Amazonas, 2017. https://tede.ufam.edu.br/handle/tede/6388.

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FAPEAM - Fundação de Amparo à Pesquisa do Estado do Amazonas
Despite advances in education, middle school classes, usually, are conducted with an excess of memorization and lack of meaning, in addition to the didactic potential of the experiments being poorly explored. The insertion of chemical concepts through contextualized approaches motivated the accomplishment of this work, which took into consideration the following question: How to approach scientific and meaningful knowledge in High School, using Forensic Chemistry in a contextualized way? In this sense, the study presents a proposal of learning through the forensic chemistry linked to the daily life of the student. In the mini-course format, we seek to investigate the learning of chemical concepts through forensic experiments in a third year high school class. The research conducted in a qualitative approach, was applied in the SESC José Roberto Tadros, western zone of Manaus-AM (Brazil). The participants were third year high school students and a chemistry teacher, having as instruments of data collection questionnaires and semi-structured interview. The analysis of the data was organized under the light of the Discursive Textual Analysis (DTA), proposed by Moraes and Galiazzi (2007). The results showed that students have difficulty in learning concepts, and that, through contextualized classes, there was more assimilation of chemical concepts by them. We believe that, by working with chemical concepts in parallel with the execution of thematic experiments, it is possible to promote Significant Learning, considering that all the experiments evaluated are perfectly consonant with the contents of High School. Therefore, with this study, it is hoped to promote the learning of students' concepts through thematic activities, such as Forensic Chemistry, in addition to enriching the learning of Chemistry.
Apesar dos avanços na Educação, comumente as aulas de Ensino Médio são conduzidas com um excesso de memorização e falta de significado, além do potencial didático dos experimentos ser deficientemente explorados. A inserção de conceitos químicos por meio de abordagens contextualizadas motivou a realização deste trabalho, que levou em consideração a seguinte questão: Como abordar conhecimento científico e significativo no Ensino Médio utilizando a Química Forense de maneira contextualizada? Neste sentido, o estudo apresenta uma proposta de aprendizagem por meio da química forense ligada ao cotidiano do aluno. No formato de minicurso, buscamos investigar a aprendizagem de conceitos químicos por meio dos experimentos forenses em uma turma de terceiro ano do Ensino Médio. A pesquisa, conduzida em uma abordagem qualitativa, foi aplicada no SESC José Roberto Tadros, Zona Oeste, Manaus-AM. Os participantes foram alunos do terceiro ano do Ensino Médio e um professor de química, tendo como instrumentos de coleta de dados questionários e entrevista semiestruturada. A análise dos dados foi organizada à luz da Análise Textual Discursiva (ATD), proposta por Moraes e Galiazzi (2007). Os resultados evidenciaram que os alunos têm dificuldades na aprendizagem de conceitos, e que, por meio de aulas contextualizadas, houve maior assimilação de conceitos químicos por eles. Acreditamos que trabalhando conceitos químicos em paralelo com a execução de experimentos temáticos é possível promover uma Aprendizagem Significativa, tendo em vista que todos os experimentos avaliados estão perfeitamente consonantes com o conteúdo de Ensino Médio. Portanto, com este estudo, espera-se promover a aprendizagem de conceitos dos alunos por meio de atividades temáticas, tais como Química Forense, além de enriquecer o aprendizado da Química.

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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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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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Zwilling, Melissa. "Analysis of White Latex Paints using Laser Induced Breakdown Spectroscopy for Forensic Applications." FIU Digital Commons, 2014. http://digitalcommons.fiu.edu/etd/1590.

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The analysis of white latex paint is a problem for forensic laboratories because of difficulty in differentiation between samples. Current methods provide limited information that is not suitable for discrimination. Elemental analysis of white latex paints has resulted in 99% discriminating power when using LA-ICP-MS; however, mass spectrometers can be prohibitively expensive and require a skilled operator. A quick, inexpensive, effective method is needed for the differentiation of white latex paints. In this study, LIBS is used to analyze 24 white latex paint samples. LIBS is fast, easy to operate, and has a low cost. Results show that 98.1% of variation can be accounted for via principle component analysis, while Tukey pairwise comparisons differentiated 95.6% with potassium as the elemental ratio, showing that the discrimination capabilities of LIBS are comparable to those of LA-ICP-MS. Due to the many advantages of LIBS, this instrument should be considered a necessity for forensic laboratories.

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Bostock, Esta. "Megaselia scalaris (Diptera: Phoridae), a fly of forensic interest : advances in chronobiology and biology." Thesis, University of Huddersfield, 2015. http://eprints.hud.ac.uk/id/eprint/26168/.

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Megaselia scalaris (Diptera, Phoridae) is a common species found amongst indoor and outdoor crime scenes and plays an important role in the decomposition of human remains and can be used following the forensic entomology approach for the estimation of the post mortem interval particularly in indoor cases. Several questions concerning the biology and the chronobiology of this species remain open. Circadian clocks have evolved to synchronize physiology, metabolism and behaviour to the 24-h geophysical cycles of the Earth. The understanding of the circadian clock mechanism is a crucial element of forensic entomology because it is able to control routines such as feeding, mating, ovipositing or emergence times. To describe the behaviour and the potential role that the circadian clock may have on both the locomotor activity and emergence times of the M.scalaris, using Trikinetics technology, used previously in Drosophilia studies allows for factual data rather than observational data seen in many journals. The activity rhythms of M.scalaris were monitored using light/dark photoperiods at 20 °C. Males and females both demonstrate that there are significant differences between dark and light conditions and further results establish that the flies are both diurnal and nocturnal in activity. The pupa emergence shows that there are different rhythms during full darkness conditions and light/dark conditions. In addition our experiments demonstrated that the activity of this species is clock regulated. Differences in locomotor activity between male and female flies were observed in the absence of food in continuous dark (DD), in contrast the activity of the two sexes don’t differ in continuous light (LL) or in presence of food both in DD and in LL conditions. Cold White, Blue, Green, Red and Yellow lights were used to test the light attractiveness. Males and females show different behaviour. In contrast females seem to be attracted to red light and they don’t present any directional behaviour under other light. Colonisation of carrion by insects allow for the post mortem interval (PMI) to be determined. However it is thought by some, that flies are not active during the night time period and therefore are not able to oviposit during this time. To put that into a forensic context, if eggs were located on a cadaver, the conclusion would be that death occurred during the previous day or before. Determining nocturnal oviposition in forensically important flies is of fundamental importance so that the PMI can be determined correctly by the forensic entomologist. Our experiments have demonstrated that M.scalaris were able to oviposit in dark conditions during the night. Insects colonise a cadaver in a predictable pattern otherwise known as the succession. Succession patterns may vary due to intrinsic and environmental factors, for example, has the cadaver been buried or is it located above ground. Colonisation in buried remains depend on the slower decomposition rate of buried bodies, reduced dispersion of the decomposition odours but as well the reduced accessibility to the body. Phoridae are commonly found amongst the entomofauna of exhumed bodies or coffins. The phorid M.scalaris has been reported as being able to dig up to 6 feet. Little information is available about the kind of soil this fly is able to dig through to reach a cadaver; two different kinds of soil were investigated: sand and sandy loam garden soil. The results showed that M.scalaris was able to excavate garden soil but not sand. Insect development rate is mainly temperature dependent, although other parameters like photoperiod, overcrowding and food availability can affect the developments. In addition several studies demonstrated that drugs and other chemicals can affect the growth of larvae, feeding on the dead body, leading to Inc.orrect mPMI estimations. Amitriptyline is a commonly used antidepressant in cases of major depressive disorder. It is a tricyclic molecule absorbed in the gastrointestinal tract and metabolized into the liver. This molecule shows a high toxicity results in cases of overdose. Studies on the effect of Amitriptyline on insect development and accumulation/excretion have been performed in the 1990’s on Parasarcophaga ruficornis (Diptera: Sarcophagidae) and on Calliphora vicina (Diptera: Calliphoridae) whereas no data are available for other taxa. The results of these studies demonstrated the non-effect of the molecule on the growth rate. In the same years Amitriptyline and derivates have been isolated from empty puparia of Megaselia scalaris and from skin and faecal material of Dermestes maculatus (Coleoptera: Dermestidae) collected from a mummified body in New England. The aim of our study was to investigate the effect that Amitriptyline, often found on cadavers, may have on the development of Megaselia scalaris. Our experiment showed that Amitriptyline had no effect on the size but saw a decrease in the developmental time of M.scalaris, so the mPMI estimation can be affected if based on the larval size and not on the complete development. The results reported and discussed in this thesis improve the knowledge about the biology of M.scalaris and its applicability in the forensic context.

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Jäverfalk-Hoyes, Emmy. "Development of methods in CE, CE-MS and MS/MS : applications in pharmaceutical, biomedical and forensic sciences /." Uppsala : Acta Universitatis Upsaliensis : Univ.-bibl. [distributör], 2001. http://publications.uu.se/theses/91-554-5107-1/.

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White, P. C. "HPLC multiwavelength UV/visible detection and separation techniques for the characterisation of acidic dyes encountered in forensic science." Thesis, Brunel University, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.293000.

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May, Christopher David. "Development of novel analytical and interpretational protocols to facilitate the provenance establishment of glass and plastic evidence." University of Western Australia. Centre for Forensic Science, 2009. http://theses.library.uwa.edu.au/adt-WU2009.0169.

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[Truncated abstract] The analysis and subsequent interpretation of trace evidence is of paramount importance to the forensic scientist. While a variety of methods are available to facilitate comparison between recovered and control samples, the use of a specific analytical method depends upon both the physical and chemical nature of the material itself and the material to which it is to be compared. Elemental analysis of evidentiary material is one such method of sample comparison and has been extensively applied to this purpose following the introduction of neutron activation analysis in the early 1960s. However, over the last 15 years, another instrumental technique has taken centre stage in the analytical armoury of the forensic scientist: laser ablationinductively coupled plasma-mass spectrometry (LA-ICP-MS). The modification and adaptation of this technique, to a point where it is possible to distinguish between glass materials produced only hours apart on the same production line, is detailed in this thesis. Additional protocols have also been developed for the analysis of fibreglass and plastic crime scene debris. Finally, a method for quantification of elemental concentrations in headlamp plastics has also been developed to facilitate inter-comparison of data between both different analytical techniques and different laboratories. Glass material is one of the most common varieties of trace evidence and the forensic examination of glass traditionally involves the determination of its refractive index (RI). ... The analytical protocol involves the analysis of 46 analytes on material comprising the exterior surface of the lens. Using this data, it was found that although minor variations in elemental composition exist within a single headlamp lens, discrimination between lenses produced from a single manufacturing plant over a short period of time could still be achieved. Discrimination between all headlamp lenses, with the exception of some lenses produced on the same day, could be facilitated using the analytical protocol developed. Furthermore, an interpretational protocol has been developed that has successfully classified all unknown headlamp lens samples investigated in this study, within the discrimination limits of the analytical method. The semi-quantitative analysis of glass and plastic samples has also been examined using LA-ICP-MS. The concentrations of 16 analytes in container and float glass samples were determined. However, the levels of discrimination afforded by the semi-quantitative data were inferior to those achieved using qualitative data. Finally, a series of plastic-based standards, containing 25 analytes of known concentrations, was produced. Using these standards, relative concentrations of the study analytes were determined in polycarbonate headlamp lenses. Interpretation of the data produced made it possible to discriminate between all study samples. Consequently, the total analytical and interpretational protocol developed in this study has established the foundation for LA-ICP-MS to be adopted internationally as a recognised method for the analysis of plastic crime scene debris.

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Grove, Alida Amelia. "The forensic analysis of illicit Methaqualone-containing preparations by gas chromatography mass spectrometry." Pretoria : [s.n.], 2005. http://upetd.up.ac.za/thesis/available/etd-02202007-171049.

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Williams, Kristina Charlene. "Direct Inject Mass Spectrometry for Illicit Chemistry Detection and Characterization." Thesis, University of North Texas, 2016. https://digital.library.unt.edu/ark:/67531/metadc849747/.

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The field of direct inject mass spectrometry includes a massive host of ambient ionization techniques that are especially useful for forensic analysts. Whether the sample is trace amounts of drugs or explosives or bulk amounts of synthetic drugs from a clandestine laboratory, the analysis of forensic evidence requires minimal sample preparation, evidence preservation, and high sensitivity. Direct inject mass spectrometry techniques can rarely provide all of these. Direct analyte-probed nanoextraction coupled to nanospray ionization mass spectrometry, however, is certainly capable of achieving these goals. As a multifaceted tool developed in the Verbeck laboratory, many forensic applications have since been investigated (trace drug and explosives analysis). Direct inject mass spectrometry can also be easily coupled to assays to obtain additional information about the analytes in question. By performing a parallel artificial membrane assay or a cell membrane stationary phase extraction prior to direct infusion of the sample, membrane permeability data and receptor activity data can be obtained in addition to the mass spectral data that was already being collected. This is particularly useful for characterizing illicit drugs and their analogues for a biologically relevant way to schedule new psychoactive substances.

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Stanley, Floyd E. III. "Advancing Modern Forensic Investigations Through The Use of Various Analytical Techniques." University of Cincinnati / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1321372527.

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Donato, Adriana De. "Desenvolvimento, comparação e aplicação forense de sistemas de injeção em banho e injeção em fluxo, com detecção voltamétrica de chumbo em eletrodo de mercúrio." Universidade de São Paulo, 2001. http://www.teses.usp.br/teses/disponiveis/46/46133/tde-23112018-165441/.

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Para determinar baixas concentrações de chumbo, oriundo de resíduos de disparo de armas de fogo, aplicou-se a voltametria de redissolução anódica, ASV, com pulso diferencial, PD, para detecção do metal em eletrodo de gota pendente de mercúrio, EGPM. A etapa de redução se dava a -0,6 V vs. Ag/AgCl, durante 25s, com imediata varredura até -0,3V vs. Ag/AgCl. O pico de reoxidação do chumbo surgia a -0,42V vs. Ag/AgCl. A injeção de amostras foi bastante facilitada pela aplicação do sistema de análise por injeção em banho, BIA onde um pequeno volume de amostra é injetado, com o auxílio de um micropipetador automático, diretamente sobre um detector imerso em um volume várias vezes maior que aquele da amostra. Com o intuito de estender a técnica ao EGPM comercial, um adaptador simples, em forma de J, foi desenvolvido e aplicado, o qual dirige o fluxo descendente do micropipetador para cima, diretamente sobre a gota de mercúrio. Foi dada a presença de chumbo, da ordem de 1 ppm, quando se amestrava as mãos encontro de voluntários, do Instituto de Criminalística da Polícia Científica do Estado de São Paulo, com tiras de fita crepe antes e depois de um conjunto de disparos. A extração do chumbo foi feita através da agitação de cada tira de fita crepe, apoiada em tela de Nylon®, com uma mistura de clorofórmio e HCl 0,1 M, com a fase aquosa sendo levada a posterior análise. Outros métodos de coleta também foram testados. Nota-se, também, que é possível determinar o mesmo analito em sistemas de injeção em fluxo, após desoxigenação do eletrólito suporte. Com o uso da técnica de pulso reverso, a desoxigenação pode se tornar desnecessária.
In order to determine low concentrations of lead, originated from gunshot residues, anodic stripping voltammetry, ASV, with differential pulse, DP, was applied to detect the metal in a hanging mercury drop electrode, HMDE. The reduction step was done at -0.6 V vs. Ag/AgCl, for 25s, followed by the immediate scan up to -0.3V vs. Ag/AgCl. The reoxidation current peak appeared at -0.42V vs. Ag/AgCl. The injection of samples was greatly facilitated by the application of the batch injection analysis system, BIA, where a small sample volume is injected, with the aid of an automatic micropipettor, directly onto the detector, which is immersed in a volume many times larger than the sample. Aiming the application of the technique with commercial HMDE, a simple J-shaped adapter was developed and applied, which directs upwards the descending flow of the micropipettor, rightly over the mercury drop surface. The presence of lead was observed at around 1 ppm, after sampling the hands of volunteers, from the Institute of Criminalistics of the Scientific Police of São Paulo State, with strips of adhesive tapes before and after a set of gunshots. Lead extraction was performed shaking each strip, over a Nylon® screen, in a mixture containing chloroform and HCl 0.lM, with the posterior analysis of the aqueous phase. Other collection methods were also tried. It is also possible to determine the same analyte in a flow injection system, after the deoxygenation of the supporting electrolyte. With the aid of the reverse pulse technique, the deoxygenation may become unnecessary.

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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.
Ph.D.
Department of Chemistry
Sciences
Chemistry PhD

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40

Balbino, Marco Antonio. "Estudo do comportamento eletroquímico do 9-tetraidrocanabinol derivatizado com Fast Blue B." Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/59/59138/tde-01122014-231252/.

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A maconha é a droga ilícita mais consumida no mundo, tem como substância psicoativa o delta-9-tetraidrocanabinol (9-THC). Os testes colorimétricos são normalmente realizados em amostras de maconha (e para qualquer outra droga ilícita) apreendidas. A adição de reagentes específicos em uma solução de extrato de maconha pode indicar a presença de substância ilícita mediante mudança de cor. No entanto, a literatura recentemente tem relatado ocorrências de resultados falso-positivos quando os testes colorimétricos são aplicados em algumas folhagens de diversas espécies de plantas. Este estudo utilizou as técnicas voltamétricas em meio orgânico N-N-dimetilformamida utilizando tetrafluoroborato de tetrabutilamônio como eletrólito de suporte e eletrodos de trabalho de disco de carbono vítreo e platina. Aplicando-se um potencial de pré concentração em - 0,5 V, verifica-se um pico de corrente anódica em ± 0,01 V vs Ag/AgCl ,KCl(sat). Utilizando eletrodo de disco de carbono vítreo como eletrodo de trabalho, na modalidade de onda quadrada, obteve-se uma dependência linear na faixa de concentração entre 1,0 x 10-9 mol L-1 a 2,2 x 10-8 mol L-1, com um coeficiente de correlação linear em 0,999 e um limite de detecção de 6,2 x 10-10 mol L-1. Tais resultados possibilitaram a determinação de 9-THC na ordem de nmol L-1.
Marijuana, the illicit drug that is most consumed worldwide, contains 9-tetrahydrocannabinol (9-THC) as the main psychoactive substance. Presumptive colorimetric tests are usually performed on seized marijuana (or any illicit drug) samples: the addition of specific reagents to the marijuana extract solution prompts a change in. This study was developed using voltammetric techniques in organic medium (N,N-dimethylformamide) using tetrabutylammonium tetrafluoroborate (TBATFB) as supporting electrolyte, and glassy carbon and platinum disc as working electrode. Applying a pre-concentration potential of -0.5 by square-wave voltammetry, we detected a well-defined anodic peak current in ± 0.01 V versus Ag/AgCl, KCl(sat); 9-THC detection presented linear dependence at concentrations ranging from 1.0 × 10-9 mol L-1 to 2.2 × 10-8 mol L-1, with a linear correlation coefficient 0.999 and a detection limit of 6.2 × 10-10 mol L-1, using the glassy carbon disc working electrode.

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41

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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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.

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.

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.

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.

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42

Eckberg, Melanie N. "Forensic Toxicological Screening and Confirmation of 800+ Novel Psychoactive Substances by LC-QTOF-MS and 2D-LC Analysis." FIU Digital Commons, 2018. https://digitalcommons.fiu.edu/etd/3923.

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Novel psychoactive substances (NPS) represent a great challenge to toxicologists due to the ability of illicit drug manufacturers to alter NPS chemical structures quickly and with ease to circumvent legislation regulating their use. Each time a new structure is introduced, there is a possibility that it has not been previously recorded in law enforcement or scientific databases. Many toxicology laboratories use targeted analytical methods that rely on libraries of known compounds to identify drugs in samples. However, these libraries do not include large numbers of NPS which could result in non-identification or detection. High-resolution mass spectrometry (HRMS) has been suggested as a method for screening a wide variety of analytes due to its higher sensitivity and mass accuracy as compared to some other forms of mass spectrometry. This technique can generate characteristic MS/MS spectral data for use in compound identification. The main goal of this research was to create a high-resolution mass spectrometry (HRMS) library of NPS and metabolites, as well as validate a method for screening and confirmation of these substances. The study consisted of three main tasks which included; the development of a large high-resolution MS/MS spectral library and database, validation of a method for screening and confirmation of over 800 NPS and metabolites, and screening of blind-spiked and authentic urine specimens to determine real-world applicability of the HRMS library and method. During validation, several isomeric and structurally related NPS were observed which could not be adequately separated using traditional LC methods. A fourth task was therefore added to investigate improved separation using two-dimensional liquid chromatography (2D-LC). Increased resolving power is achieved in 2D-LC through the coupling of multiple orthogonal separation systems. Ultimately, an on-line, comprehensive method was developed using orthogonal reversed-phase columns in each dimension (RP x RP) for improved separation of co-eluting and isomeric synthetic cannabinoids. This work can aid laboratories in the identification of NPS through the use of a validated LC-QTOF-MS method for screening and confirmation and HRMS spectral library. In instances where isomeric and structurally related NPS are not sufficiently separated, RP x RP methods can be explored.

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43

Breidi, Salah Eddine. "Development of methods to determine analytes in a variety of matrices with applications to forensic science." Thesis, Kingston University, 2014. http://eprints.kingston.ac.uk/32194/.

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This thesis comprises of studies based on the broad field of forensic analysis and the development of methods which can be applied to different matrices. The initial studies focus on the forensic determination of psychoactive drugs in hair matrix using newly deve1oped gas chromatography-mass spectrometry analytical methods. The second study focuses on the discrimination and matching of skid marks and rubber tyre analysis by using novel chemical analysis methods. This thesis reports the deve1opment and application of a series of innovative analytical methods: gas chromatography-mass spectrometry, inductively coupled plasma mass spectrometry, pyrolysis-gas chromatography-mass spectrometry and attenuated total reflection Fourier transform infrared spectroscopy. Gas Chromatography-Mass Spectrometric (GC-MS) methods for drug analysis routinely employ derivatising reagents. The aim of the first study was to develop a method for the analysis of two recreational drugs, delta-9-tetrahydrocannabinol (delta-9- THC) and cocaine in hair samples using GC-MS, without prior derivatisation, thus allowing the sample to be analysed in its original form. Ten hair samples, that were positive to ELISA analysis for either delta 9-THC and/or cocaine, were enzymatically digested, extracted and then analysed by gas chromatography-mass spectrometry. All samples measured contained delta 9-THC and one sample contained cocaine. The limits of detection (LOD) and quantification (LOQ) were 0.02 ng/mg & 0.05 rig/mg, respectively for cocaine and 0.015 ng/mg & 0.02 ng/mg, respectively for A9-THC. The wide detection window, ease of direct analysis by GC-MS, lower detection limits of un-derivatised samples and the stability of drugs using this technique offers an improved method of analysis. This experiment has been designed to develop an immunological screening test followed by a GC-MS confirmation method for the simultaneous analysis of delta 9- THC, THC-COOH, , OH-THC, cocaine, Benzoylecgonine (BZ), amphetamine (AP), methamphetamine (MA), in human hair, thus avoiding the significant factors responsible for drug degradation by acid and alkali hydrolysis and to obtain optimal recovery conditions. Enzymatic hair digestion was used to hydrolyse 18 Turkish samples using Proteinase K, Dithiothreitol and Tris HCl buffer. At the beginning, all 18 samples tested screened positive on ELISA, though analysis by GC-MS indicated that only 2 samples were positive for delta 9-THC and THC-COOH. Cross reaction lead to false positive results in the pre-screening step as a result of the degradation of the antibodies in the pre-coated ELISA microplate. Tyre rubber analysis Owing to an increase in the number of hit and run accidents, it is quite common for rubber traces to be left at the crime scene. The Forensic Scientist will have the task of analysing the tyre striation traces in order to identify the type of tyre involved in the accident. However, the tyre striations alone do not provide enough detail to show a high level of discrimination between different tyre manufacturers and individual models. In this study, Inductively Coupled Plasma Mass Spectrometry (ICP-MS), Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR-FI‘IR) and pyrolysis GC-MS methods were developed to enable greater discrimination between different tyre rubber samples. Seventy elements were screened for each sample by ICP-MS in both collision cell mode and reaction cell mode. ATR-FTIR analysis indicated a low intra-variability (analysis of similar tyres) which demonstrated high precision of the technique, and also showed a large inter-variability between different manufacturers and models, which supports their high potential as indicators to be used for discrimination between different tyres manufacturers and models. Principal Component Analysis (PCA) was utilised to distinguish between the different tyres.

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44

Buxton, Tricia L. "Solving Problems in Ion Mobility Measurements of Forensic Samples with Thermal Desorption and Dynamic Modeling." Ohio University / OhioLINK, 2002. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1019244669.

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45

Corzo, Ruthmara. "Elemental Characterization of Printing Inks and Strengthening the Evaluation of Forensic Glass Evidence." FIU Digital Commons, 2018. https://digitalcommons.fiu.edu/etd/3814.

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Improvements in printing technology have exacerbated the problem of document counterfeiting, prompting the need for analytical techniques that better characterize inks for forensic analysis. In this study, 319 printing inks (toner, inkjet, offset, and intaglio) were analyzed directly on the paper substrate using Scanning Electron Microscopy-Energy Dispersive Spectroscopy (SEM-EDS) and Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry (LA-ICP-MS). As anticipated, the high sensitivity of LA-ICP-MS resulted in excellent discrimination (> 99%) between ink samples originating from different sources. Moreover, LA-ICP-MS provided ≥ 90% correct association for ink samples originating from the same source. SEM-EDS resulted in good discrimination for toner and intaglio inks (> 97%) and excellent correct association (100%) for all four ink types. However, the technique showed limited utility for the discrimination of inkjet and offset inks. A searchable ink database, the Forensic Ink Analysis and Comparison System (FIACS), was developed in order to provide a tool that allows the analyst to compare a questioned ink sample to a reference population. The FIACS database provided a correct classification rate of 94-100% for LA-ICP-MS and 67-100% for SEM-EDS. An important consideration in forensic chemistry is the interpretation of the evidence. Typically, a match criterion is used to compare the known and questioned sample. However, this approach suffers from several disadvantages, which can be overcome with an alternative approach: the likelihood ratio (LR). Two LA-ICP-MS glass databases were used to evaluate the performance of the LR: a vehicle windshield database (420 samples) and a casework database (385 samples). Compared to the match criterion, the likelihood ratio led to improved false exclusion rates (< 1.5%) and similar false inclusion rates (< 1.0%). In addition, the LR limited the magnitude of the misleading evidence, providing only weak support for the incorrect proposition. The likelihood ratio was also tested through an inter-laboratory study including 10 LA-ICP-MS participants. Good correct association rates (94-100%) were obtained for same-source samples for all three inter-laboratory exercises. Moreover, the LR showed a strong support for an association. Finally, all different-source samples were correctly excluded with the LR, resulting in no false inclusions.

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46

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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47

Bishop, Sandra Charlotte. "Advanced capillary electrophoretic techniques for the detection of date-rape and club drugs for a forensic setting." Ohio : Ohio University, 2004. http://www.ohiolink.edu/etd/view.cgi?ohiou1107528810.

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48

Rafael, Venson. "Hollow-fibre liquid-phase microextraction : investigation into the potential use in clinical and forensic toxicology." Thesis, University of Glasgow, 2017. http://theses.gla.ac.uk/8697/.

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Hollow-fibre liquid-phase microextraction (HF-LPME) was introduced in 1999 as a miniaturised version of liquid-liquid extraction (LLE) in order to reduce the consumption of organic solvents and offer an environmentally-friendly approach to extraction procedures. Since then, several studies have been published in the field of forensic and clinical toxicology applying the technique to a broad range of analytes; however more studies are necessary regarding its applicability to bioanalyses. The principle of HF-LPME is the extraction of analytes across a thin supported liquid membrane within the walls of a hollow fibre from a donor phase (DP) into an acceptor phase (AP). It is an extraction technique that encompasses several parameters that require optimisation for an efficient method; this is most effectively achieved by utilising a design of experiment (DoE) approach rather than the conventional one-factor-at-a-time (OFAT) approach. The main aim of this work is to further investigate the applicability of HF-LPME to the fields of forensic and clinical toxicology by developing and validating methods to extract various drugs from different biological matrices. Complex matrices, such as whole blood, are commonly used in forensic toxicology. Considering that not many studies have been performed on the application of HF-LPME to whole blood (only 10 up to the present day), this is an aspect that requires further investigation. For this, a fast, accurate and precise 3-phase HF-LPME method followed by LC-MS/MS analysis was developed and validated to simultaneously quantify 5 NBOMe drugs in human whole blood. NBOMe drugs are a group of substances part of the so-called “novel psychoactive substances” (NPS); drugs that have been emerging with increasing frequency over the last few years. NBOMes are associated to deaths as the causa mortis, and due to their high potency, these drugs are normally abused in micrograms. For that reason, the HF-LPME method developed had to present high sensitivity (LOD of pg/mL). The aim of the second part of this project was to challenge HF-LPME further by developing and validating methods to assess the potential application of HF-LPME in multi-drug analyses. Urine was selected as biological matrix, and the group of chosen analytes were 14 anti-hypertensive drugs and their metabolites with very different physical-chemical properties. HF-LPME has never been applied to such a broad spectrum of substances in previous bioanalytical studies. These drugs were divided into two groups (acidic and basic/neutral), and a total of four extraction methods (two for each group of analytes) were developed and optimised using chemometrics (DoE) then analysed by LC-MS/MS. Two of these methods were liquid-liquid extraction (LLE) methods that were developed and validated to be used as reference to which the two HF-LPME methods were compared. The LLE methods were sensitive, accurate, precise, and valid for application to real case samples. The HF-LPME methods presented some limitations due to the lack of isotopically-labelled analogues of each specific analyte as internal standards (IS); for non-exhaustive methods the use of these IS should be adopted as standard practise. Real urine samples from genuine patients were extracted using all 4 methods followed by LC-MS/MS analysis. By applying the methods to real case samples, it was possible to define that the HF-LPME methods were suitable for qualitative screening of urine to determine the level of compliance of patients under anti-hypertensive pharmacotherapy. However, for quantification of the drugs applying HF-LPME, further development is required to incorporate the use of isotopically labelled analogues. This study proved that HF-LPME is a potential asset not only for forensic but also for clinical toxicology. It can be a very powerful tool which, mainly due to its green-chemistry approach and pre-concentration capabilities, which allows direct injection into the analytical instrument, could potentially become a more used technique in the future. However, the analyst should be careful when developing HF-LPME methods, to bear in mind its limitations so that methods that are fit-for-purpose can be developed.

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Collin, Olivier L. "Development of a Novel Tandem Mass Spectrometry Technique for Forensic and Biological Applications." View abstract, 2007. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:3292877.

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50

Brown, Jessica S. "Determination of Signature Volatile Odor Chemicals Emanating from Novel Biological Specimens by Non-invasive Analytical Techniques for the Potential use in Forensic Identifications." FIU Digital Commons, 2012. http://digitalcommons.fiu.edu/etd/737.

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Human scent, or the volatile organic compounds (VOCs) produced by an individual, has been recognized as a biometric measurement because of the distinct variations in both the presence and abundance of these VOCs between individuals. In forensic science, human scent has been used as a form of associative evidence by linking a suspect to a scene/object through the use of human scent discriminating canines. The scent most often collected and used with these specially trained canines is from the hands because a majority of the evidence collected is likely to have been handled by the suspect. However, the scents from other biological specimens, especially those that are likely to be present at scenes of violent crimes, have yet to be explored. Hair, fingernails and saliva are examples of these types of specimens. In this work, a headspace solid phase microextraction gas chromatography-mass spectrometry (HS-SPME-GC-MS) technique was used for the identification of VOCs from hand odor, hair, fingernails and saliva. Sixty individuals were sampled and the profiles of the extracted VOCs were evaluated to assess whether they could be used for distinguishing individuals. Preliminary analysis of the biological specimens collected from an individual (intra-subject) showed that, though these materials have some VOCs in common, their overall chemical profile is different for each specimen type. Pair-wise comparisons, using Spearman Rank correlations, were made between the chemical profiles obtained from each subject, per a specimen type. Greater than 98.8% of the collected samples were distinguished from the subjects for all of the specimen types, demonstrating that these specimens can be used for distinguishing individuals. Additionally, field trials were performed to determine the utility of these specimens as scent sources for human scent discriminating canines. Three trials were conducted to evaluate hair, fingernails and saliva in comparison to hand odor, which was considered the standard source of human odor. It was revealed that canines perform similarly to these alternative human scent sources as they do to hand odor implying that, though there are differences in the chemical profiles released by these specimens, they can still be used for the discrimination of individuals by trained canines.

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Dissertations / Theses on the topic 'Forensic chemistry'

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