Determination of 22 synthetic cannabinoids in human hair by liquid chromatography–tandem mass spectrometry

Herbal mixtures of the “Spice“-type contain a variety of synthetic cannabinoids. To prove the contact of a person with synthetic cannabinoids in a previous period of up to several months, hair testing is ideally suited. A rapid, simple and sensitive liquid chromatography–tandem mass spectrometry (LC–MS/MS) assay was developed to determine 22 synthetic cannabinoids in human hair. The synthetic cannabinoids JWH-007, JWH-015, JWH-018, JWH-019, JWH-020, JWH-073, JWH-081, JWH-122, JWH-200, JWH-203, JWH-210, JWH-250, JWH-251, JWH-398, AM-694, AM–2201, methanandamide, RCS-4, RCS-4 ortho isomer, RCS-8, WIN 48,098 and WIN 55,212-2 were extracted from 50 mg hair by 3-h ultrasonification in ethanol. The extracts were analysed on a triple-quadrupole linear ion trap mass-spectrometer in scheduled multiple reaction monitoring mode (sMRM). The method was fully validated and proved to be accurate, precise, selective and specific with satisfactory linearity within the calibrated range and a lower limit of quantification of 0.5 pg/mg for 20 compounds. Authentic hair samples from chronic consumers showed the presence of two to six synthetic cannabinoids in the same segment. In the first segment, concentrations of up to 78 pg/mg JWH-081 were present. In segmented hair, the concentrations of most substances increased from the first (proximal) to the third segment. The highest concentration was ca. 1100 pg/mg JWH-081. The results of segmental hair analysis in chronic users suggest incorporation of the drugs in head hair via side-stream smoke condensation as a major route. In summary, the method can be used to prove the contact with herbal mixtures containing synthetic cannabinoids and thus contributes to an efficient abstinence control.