Alternative matrices in forensic toxicology: a critical review

Eduardo Geraldo De Campos,Wilson José Ramos Santos Junior,Bruno Spinosa De Martinis,Fernanda Monedeiro,Fabiana Spineti Dos Santos,Bruno Ruiz Brandão Da Costa,Marcela Nogueira Rabelo Alves

doi:10.1007/s11419-021-00596-5

Eduardo Geraldo De Campos, Wilson José Ramos Santos Junior + Show 5 more

Open Access

https://doi.org/10.1007/s11419-021-00596-5

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Abstract

PurposeThe use of alternative matrices in toxicological analyses has been on the rise in clinical and forensic settings. Specimens alternative to blood and urine are useful in providing additional information regarding drug exposure and analytical benefits. The goal of this paper is to present a critical review on the most recent literature regarding the application of six common alternative matrices, i.e., oral fluid, hair, sweat, meconium, breast milk and vitreous humor in forensic toxicology.MethodsThe recent literature have been searched and reviewed for the characteristics, advantages and limitations of oral fluid, hair, sweat, meconium, breast milk and vitreous humor and its applications in the analysis of traditional drugs of abuse and novel psychoactive substances (NPS).ResultsThis paper outlines the properties of six biological matrices that have been used in forensic analyses, as alternatives to whole blood and urine specimens. Each of this matrix has benefits in regards to sampling, extraction, detection window, typical drug levels and other aspects. However, theses matrices have also limitations such as limited incorporation of drugs (according to physical–chemical properties), impossibility to correlate the concentrations for effects, low levels of xenobiotics and ultimately the need for more sensitive analysis. For more traditional drugs of abuse (e.g., cocaine and amphetamines), there are already data available on the detection in alternative matrices. However, data on the determination of emerging drugs such as the NPS in alternative biological matrices are more limited.ConclusionsAlternative biological fluids are important specimens in forensic toxicology. These matrices have been increasingly reported over the years, and this dynamic will probably continue in the future, especially considering their inherent advantages and the possibility to be used when blood or urine are unavailable. However, one should be aware that these matrices have limitations and particular properties, and the findings obtained from the analysis of these specimens may vary according to the type of matrix. As a potential perspective in forensic toxicology, the topic of alternative matrices will be continuously explored, especially emphasizing NPS.

Highlights

One of the goals of forensic toxicology is to apply approaches of analytical chemistry, toxicology and pharmacology for investigating compounds of forensic interest in samples collected in casework including death investigations, driving under the influence of substances, doping control, drug-facilitated crimes and more
It is of paramount importance to investigate the presence of a given drug in biological fluids collected from the individual in a suspected-intoxication case, since this would be important evidence of drug intake
Modern advancements in instrument’s technology have made possible the exploration and analysis of alternative matrices; modern and sensitive instruments are enabling the detection of lower concentrations of drugs and poisons in some of these alternative specimens [1]

Summary

Introduction

One of the goals of forensic toxicology is to apply approaches of analytical chemistry, toxicology and pharmacology for investigating compounds of forensic interest in samples collected in casework including death investigations, driving under the influence of substances, doping control, drug-facilitated crimes and more. Alternative biological matrices have been explored in toxicological testing, especially due to their advantages over conventional matrices [2–4] These advantages include easier and less invasive specimen collection and in some cases, larger detection windows [3]. Due to inherent characteristics and toxicokinetics, drug levels in some of these matrices may be reduced in comparison to blood or urine For this reason, modern advancements in instrument’s technology have made possible the exploration and analysis of alternative matrices; modern and sensitive instruments are enabling the detection of lower concentrations of drugs and poisons in some of these alternative specimens [1]. Some of these samples such as oral fluid and hair are already well established and have been implemented in drug testing by several laboratories

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