Physical Sciences and Mathematics Commons^™

Development Of A Dna Methylation Multiplex Assay For Body Fluid Identification And Age Determination, Quentin Gauthier

FIU Electronic Theses and Dissertations

For forensic laboratories, the determination of body fluid origin of samples collected at a crime scene are typically presumptive and often destructive. However, given that in certain cases the presence of DNA is not in dispute and rather where the DNA came from is of primary concern, new methodologies are needed. Epigenetic modifications, such as DNA methylation, affect gene expression in every cell of every mammal. These DNA methylation patterns typically are observed as the addition of a methyl group on the 5’ carbon of a cytosine followed by guanine (CpG). Methylation patterns have been observed to change in response …

Development Of Dna Methylation Markers To Infer Age, Smoking Status And Body Fluid Types For Forensic Application, Hussain J.H. Alghanim

FIU Electronic Theses and Dissertations

In forensic investigations, biological evidences have great potential to place a suspect at the scene of a crime. However, in many cases suspect(s) usually can’t be identified with any local or national databases. In such challenging cases, police need a tool that can provide investigative leads. Thus, different genetic biomarkers including DNA methylation markers have been developed for different phenotypic traits to serve as source of intelligence information to investigators in cases of unknown DNA profiles. In this project, novel sets of DNA methylation markers were developed for the forensic estimation of human age, determining the smoking status and body …

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

FIU Electronic Theses and Dissertations

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

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

Elemental Characterization Of Printing Inks And Strengthening The Evaluation Of Forensic Glass Evidence, Ruthmara Corzo

FIU Electronic Theses and Dissertations

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 …

Analysis Of White Latex Paints Using Laser Induced Breakdown Spectroscopy For Forensic Applications, Melissa Zwilling

FIU Electronic Theses and Dissertations

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 …

Elemental Analysis And Forensic Comparison Of Soils By Laser-Induced Breakdown Spectroscopy (Libs) And Laser Ablation Inductively Coupled Plasma Mass Spectrometry (La-Icp-Ms), Sarah C. Jantzi

FIU Electronic Theses and Dissertations

The elemental analysis of soil is useful in forensic and environmental sciences. Methods were developed and optimized for two laser-based multi-element analysis techniques: laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) and laser-induced breakdown spectroscopy (LIBS). This work represents the first use of a 266 nm laser for forensic soil analysis by LIBS.

Sample preparation methods were developed and optimized for a variety of sample types, including pellets for large bulk soil specimens (470 mg) and sediment-laden filters (47 mg), and tape-mounting for small transfer evidence specimens (10 mg). Analytical performance for sediment filter pellets and tape-mounted soils was similar …

The Construction And Optimization On An Ion Mobility Spectrometer For The Analysis Of Explosives And Drugs, Hanh Tuyet Lai

FIU Electronic Theses and Dissertations

Today, over 15,000 Ion Mobility Spectrometry (IMS) analyzers are employed at worldwide security checkpoints to detect explosives and illicit drugs. Current portal IMS instruments and other electronic nose technologies detect explosives and drugs by analyzing samples containing the headspace air and loose particles residing on a surface. Canines can outperform these systems at sampling and detecting the low vapor pressure explosives and drugs, such as RDX, PETN, cocaine, and MDMA, because these biological detectors target the volatile signature compounds available in the headspace rather than the non-volatile parent compounds of explosives and drugs. In this dissertation research volatile signature compounds …