Doctor of Philosophy (PhD)
First Advisor's Name
Anthony P. DeCaprio
First Advisor's Committee Title
Second Advisor's Name
Second Advisor's Committee Title
Third Advisor's Name
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Fourth Advisor's Name
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Fifth Advisor's Name
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forensic hair analysis, design of experiments, LC-QqQ, UV/Vis
Date of Defense
Forensic toxicological analysis for the purposes of protecting human health and supporting criminal justice activities can be achieved, in part, by means of analysis of human head hair for detection of abused substances. Hair is considered an alternative sample matrix (compared to blood and urine) because of persistent interpretive challenges caused by a lack of standardization in analytical approaches and poor understanding of the biases resulting from physicochemical interactions between major hair components (e.g., melanin) and drugs of abuse. Some of the uncertainty regarding optimal techniques for the pre-treatment of hair specimens results from the unknown nature of the interactions between drugs and hair components, in particular melanin. Thus, the second focus of this work was to study these interactions with select drugs and melanin by UV/Visible spectroscopy. Another source of uncertainty is attributed to the lack of standardization in the analytical approach to hair testing. As a complex solid sample matrix, hair requires pre-treatment measures including decontamination, homogenization, and extraction to remove drug from the hair components to allow for analysis. Optimizing these pre-treatment parameters is essential for accurate toxicological analysis of this matrix. Thus, a major focus of this work was to conduct a comprehensive comparison of the efficacy of decontamination and extraction variables by means of statistical design of experiments (DoE).
Major findings of this work were a minimum of four consecutive washes were necessary for the decontamination of hair and solvent swelling of the matrix resulted in the highest extraction of the five analytes under study. The other major conclusion of this work was the interaction between eumelanin and drugs is a result of ionic interactions and van der Waals forces. Additionally, association constants between drugs and eumelanin were determined to provide additional insight into the strength of interactions between drugs with different physicochemical properties and eumelanin.
These findings will impact the forensic science community by contributing to a body of research aimed at determining the most effective method(s) for decontaminating hair samples for forensic analysis, the subsequent isolation of drugs from hair, and by investigating the interactions between melanin and select drugs of abuse.
Aijala, Jennett Chenevert, "Systematic Comparison of Pre-Treatment Parameters in Forensic Hair Analysis and Investigating Hair-drug Interactions" (2020). FIU Electronic Theses and Dissertations. 4521.
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