Analysis of hair after contamination with blood containing cocaine and blood containing benzoylecgonine

Evaluation of amphetamines diffusion in hair after contact with amphetamines-containing blood

Amphetamine-type stimulants are the third most widely consumed category of illicit drugs worldwide. Faced with the growing problem of amphetamine-type stimulants, numerous qualitative and quantitative techniques have been developed to detect amphetamine (AMP), methamphetamine (MET), MDMA, MDEA or MDA in biological matrices, including hair. Hair analysis is widely used in forensic medicine, but one of its main drawbacks remains external contamination. In this study, we investigated the possibility of hair contamination through external exposure to blood containing AMP, MET MDMA, MDEA or MDA at 2 ng/mL; 20 ng/mL; 200 ng/mL or 2000 ng/mL after 6 h, 1, 3, 7 or 14 days of contact protected from light at room temperature (RT or 20 °C) or at 4 °C. Dried extracts of hair samples were analyzed by UPLC-MS/MS after extensive washings in several baths of water, methanol and acetone before grounding. At the end of our study, contamination of hair was observed from 6 h of contact with all tested amphetamine-type stimulants. The concentrations found in hair ranged from 3 ± 1 to 1464 ± 10 pg/mg, 5 ± 1 to 5070 ± 160 pg/mg, 3 ± 1 to 1269 ± 60 pg/mg, 4 ± 1 to 1860 ± 113 pg/mg and from 8 ± 1 to 1041 ± 44 pg/mg for AMP, MET, MDMA, MDEA and MDA, respectively. Possibly due to its low polar surface area, MET was the most prone to contaminate. As anticipated, hair contamination was mainly dependent on the concentration of all molecules in the contaminating blood, reaching the SOHT cut-off of 200 pg/mg when amphetamine-type stimulants are at toxic or lethal concentrations in the blood. These observations call for caution in interpreting exposure to these substances in such forensic situations.

Recent trends in analytical methods and separation techniques for drugs of abuse in hair

Hair analysis of drugs of abuse has been a subject of growing interest from a clinical, social and forensic perspective for years because of the broad time detection window after intake in comparison to urine and blood analysis. Over the last few years, hair analysis has gained increasing attention and recognition for the retrospective investigation of drug abuse in a wide variety of contexts, shown by the large number of applications developed. This review aims to provide an overview of the state of the art and the latest trends used in the literature from 2005 to the present in the analysis of drugs of abuse in hair, with a special focus on separation analytical techniques and their hyphenation with mass spectrometry detection. The most recently introduced sample preparation techniques are also addressed in this paper. The main strengths and weaknesses of all of these approaches are critically discussed by means of relevant applications.

Hair testing is taking root

An increasing number of toxicology laboratories are choosing to expand the services they offer to include hair testing in response to customer demands. Hair provides the toxicologist with many advantages over conventional matrices in that it is easy to collect, is a robust and stable matrix that does not require refrigeration, and most importantly, provides a historical profile of an individual's exposure to drugs or analytes of interest. The establishment of hair as a complementary technique in forensic toxicology is a direct result of the success of the matrix in medicolegal cases and the wide range of applications. However, before introducing hair testing, laboratories must consider what additional requirements they will need that extend beyond simply adapting methodologies already validated for blood or urine. Hair presents many challenges with respect to the lack of available quality control materials, extensive sample handling protocols and low drug concentrations requiring greater instrument sensitivity. Unfortunately, a common pitfall involves over-interpretation of the findings and must be avoided.