In 2008, some synthetic cannabinoids named “Spice” were detected in herbal smoking mixtures and became popular owing to their strong cannabimimetic effects after smoking. Many other products have appeared since and are constantly changing in attempts by manufacturers to evade legislation. Hair samples, which generally contain the parent compounds, could be of interest to screen for these synthetic cannabinoids using a poor selective extraction method and a highly specific and sensitive analytical detection technique. A simple method was developed and validated for the quantitative detection of 18 synthetic cannabinoids, AM-694; AM- 2201;CP 47,497; HU-210; JWH-007; JWH-015; JWH-018 and its N-Pentanoic acid metabolite; JWH-019; JWH-020; JWH-073; JWH-081; JWH-122; JWH-200; JWH-203; JWH-210; JWH-250 and WIN 55, 212-2 in hair by HPLC-MS/MS and its application to authentic specimen. This work belong to a pilot study evaluating the prevalence of synthetic cannabinoids use in France and conducted with two other labs²,³.

After decontamination with methylene chloride, hair sections were cut into small pieces, weighed and incubated in methanol, overnight at 40°C, in the presence of deuterated internal standards (JWH-018-d₉, THC-d₃, 11-OH-THC-d₃, THC-COOH-d₃). Finally, the organic phase was evaporated to dryness and reconstituted in mobile phase. The HPLC-MS/MS system consisted of an UFLC (Shimadzu Prominence) coupled with a triple-quadrupole ABSciex 5500 QTRAP instrument. Chromatographic separation was achieved on a Kinetex™ XB-C18 (2.1×100mm, 2.6μm) column. Tandem mass spectrometry was employed using an electrospray interface in positive and negative ionisation mode and acquisition was performed in scheduled MRM mode.

The method was linear from LQ to 500pg/mg with quantification limits ranging from 0.5 to 5pg/mg for all the targeted synthetic cannabinoids. Intra and inter-day precisions were below 20% at 0.5; 10; 50; 75 and 250pg/mg. Intra and inter-day accuracies were established to be between 80% and 120% for the same concentration levels. There was no carry over and the absence of significative ion suppression phenomena was controlled. Sixty-five authentic hair specimens obtained from our routine activity (French forensic cases) were screened for synthetic cannabinoids. None of the specimen was found positive for the 18 targeted compounds. These preliminary results are in favour with a current very low prevalence of synthetic cannabinoids use in France, and are in accordance with those obtained by the two other labs which investigated urine specimens for the same 18 compounds.

Regarding the rising scientific interest about the synthetic cannabinoids, it appears necessary to develop an accurate, sensitive, but also evolutive method for the detection and quantification of synthetic cannabinoids in hair. Liquid chromatographymass spectrometry was deemed the most suitable analytical technique for its accuracy and sensitivity, particularly after a simple and unique direct extraction step from hair using methanol. This first method version was developed and fully validated for the large screening of 18 synthetic cannabinoids in hair.