Forensic Science International, July 2018, Vol.288, pp.223-226
Drugs which are commonly smoked or sniffed (e.g. cocaine), can contaminate hair through smoke or dust; therefore testing for metabolites, especially hydroxy metabolites, is highly recommended. The presence of hydroxy metabolites in street-cocaine (COC) has been discussed. To check if detection of hydroxy metabolites definitely proves ingestion, the presence of these metabolites in street COC samples has to be checked. It is expected that the more hydrophilic hydroxy metabolites of COC are incorporated into the hair-matrix to a lesser extent. For this study 576 COC positive hair samples (≥0.1 ng COC/mg hair) were analysed by LC–MS/MS for benzoylecgonine (BE), norcocaine (NC), cocaethylene (CE), -, - and -hydroxy COC ( -, -, -OH-COC), - and -hydroxy BE ( -, -OH-BE), and - and -hydroxy NC ( -, -OH-NC). The results were compared with the respective metabolite/COC concentration ratios in 146 street COC samples, confiscated by the Bavarian police. Peak areas were used to estimate BE/COC, NC/COC, CE/COC and hydroxy metabolites/COC. Similar metabolic ratios were found for -OH-COC in 88% of the samples, but for -OH-COC and -OH-COC only in 5.1% and 6.8%, respectively. Notably, and OH-BE as well as and OH-NC could not be identified from seized samples. We propose that area ratios exceeding the ratios of street COC more than twice or identification of OH-BE and OH-NC enable to differentiate COC consumption from contamination. Using these criteria, consumption of the drug could be proven in 92% of COC positive samples. As detection of - and -hydroxy metabolites using the above mentioned criteria is a reliable tool to distinguish between ingestion and external contamination, it is recommended to implement their measurement into daily routine work.
Cocaine ; Hair Testing ; Hydroxy Metabolites ; Public Health
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