Forensic Science and Technology Commons^™

Quality Management And Oversight Of Texas Forensic Science Service Providers, Sarah P. Chu

Dissertations, Theses, and Capstone Projects

Forensic science oversight in the U.S. largely relies upon voluntary third-party forensic laboratory accreditation programs. Without a national system of regulation and given the highly fragmented local systems of control, few forensic science service providers (FSSPs) are subject to regulatory oversight beyond their third-party accreditors. Texas is unique in its establishment of a robust statewide oversight system and a strong governmental culture of transparency, permitting this study of forensic quality management. This study consisted of two parts. The first part of this dissertation characterized and analyzed quality incident reports (QIRs) published by the Texas Department of Public Safety Crime Laboratory …

A Comparison Of Methods Used For The Elimination Of Organics From Soil Prior To Analysis By Ftir-Atr And Sem-Eds, Argeliz Pomales

Student Theses

This project suggests improvements to the treatment methods utilized for the sample preparation and evaluation of minerals in soil samples encountered in forensic science casework and research. The evaluation of pre-treated and post-treated soil samples were performed using Fourier-Transform Infrared Spectroscopy with Attenuated Total Reflection (FTIR-ATR) and Scanning Electron Microscopy-Energy Dispersive Spectroscopy (SEM-EDS). Because soil samples contain a significant amount of organic matter and water which interfere with examination of these minerals while using these instruments, pretreatment methods are necessary to isolate the mineral fraction for examination and analysis.

Soil samples were first sieved with various size stainless steel mesh …

Evaluating A Test For Shedding Propensity Using Tape Lifts From Different Skin Locations, Xiao M. Chen

Student Theses

The shedding propensity of a person can assist data interpretation in casework when assessing the possibility of passive transfer for DNA analysis. Past studies on shedding propensity evaluated palmar skin (washed and unwashed) deposits. This study compared different skin locations with respect to shedding propensity, and explored the potential of tape-lifts as a skin surface collection method. Eight different skin types and samples were collected with adhesive tape disks from 28 participants over three non-consecutive days; the washed and unwashed fingers from both hands, toe, and arm, neck below ear, and nape. Samples were extracted, quantified, amplified, genotyped, and evaluated …

Evaluation Of The Potential Of Automated Sem-Eds Analysis For The Discrimination Of Inorganic Soil Particles, Anna S. Duggar

Dissertations, Theses, and Capstone Projects

Soil, that complex mixture of minerals, organic particles, chemicals, and anthropogenic materials, is ubiquitous and easily transferred, which gives it forensic relevance. Forensic soil analysis has traditionally included the identification and comparison of both organic and inorganic components, the inorganic portion being most commonly examined by light microscopy and other instrumental techniques. Predominantly, the inorganic materials in soil are naturally-occurring minerals, contributed as grains from the surrounding bedrock, which gives a soil its regional character. That parent material then undergoes physical, chemical, and anthropogenic changes producing wide geographic variation within a single region. This variation forms the basis for potential …

The Forensic Analysis Of Adult Temporary Tattoos, Paige Cooper

Student Theses

Adult temporary tattoos have become more popular, yet there is very little research on them, especially regarding their use in forensics. This poses a problem because forensic investigators may not be able to distinguish a temporary tattoo from a real tattoo, possibly hindering their investigation. In this study, various types of adult temporary tattoos were examined and analyzed in attempts to identify and distinguish them, both from each other and from permanent tattoos. Infrared spectroscopy, specifically attenuated total reflection (ATR), proved to be more useful than ultra-violet visible light spectroscopy in terms of analyzing the samples. The natural adult temporary …

The Advanced Spectroscopic Analysis Of Organic Gunshot Residue And Explosives, Jennifer M. Leonard

Dissertations, Theses, and Capstone Projects

With the prevalence of shooting cases and terrorist attacks/or threats that plague the current state of the criminal justice system, it is of paramount importance to be able to detect, identify and interpret the presence of gunshot residue or explosives material. This concern is seen in law enforcement agencies and the media throughout the United States and abroad.

Currently, the typical method of analyzing gunshot residue in most crime laboratories serves to identify the inorganic constituents of the primer residue, namely lead, barium and antimony. However, it is possible that the organic matter from the propellant could provide different information …

Quantitative Analysis Of Opioids And Cannabinoids In Wastewater Samples, Alethea Jacox, Jillian Wetzel, Shu-Yuan Cheng, Marta Concheiro-Guisan

Publications and Research

Wastewater-based epidemiology is an innovative approach that uses the analysis of human excretion products in wastewater to obtain information about exposure to drugs in defined population groups. We developed and validated an analytical method for the simultaneous determination of opioids (morphine, oxycodone, hydrocodone, oxymorphone and hydromorphone), and cannabinoids (Δ⁹-tetrahydrocannabinol, 11-nor-9-carboxy-tetrahydrocannabinol (THCCOOH) and THCCOOH-glucuronide) in raw-influent wastewater samples by ultra-high performance liquid chromatography-tandem mass spectrometry. Method validation included linearity (5–1 000 ng/L for opioids, 10–1 000 ng/L for cannabinoids), imprecision (<21.2%), accuracy (83%–131%), matrix effect (from –35.1% to –14.7%) and extraction efficiency (25%–84%), limit of detection (1–5 ng/L) and quantification (5–10 ng/L) and auto-sampler stability (no loss detected). River and wastewater samples were collected in triplicate from different locations in New York City and stored at −20 °C until analysis. Water from sewage overflow location tested positive for morphine (10.7 ng/L), oxycodone (4.2–23.5 ng/L), oxymorphone (4.8 ng/L) and hydromorphone (4.2 ng/L). Raw influent wastewater samples tested positive for morphine (133.0–258.3 ng/L), oxycodone (31.1–63.6 ng/L), oxymorphone (16.0–56.8 ng/L), hydromorphone (6.8–18.0 ng/L), hydrocodone (4.0–12.8 ng/L) and THCCOOH (168.2–772.0 ng/L). This method is sensitive and specific for opioids and marijuana determination in wastewater samples.