LC–MS/MS method for the quantitation of metabolites of eight commonly-used synthetic cannabinoids in human urine – An Australian perspective

An LC–MS/MS method for the quantitation of urinary metabolites of eight JWH-type synthetic cannabinoids (SCs) has been developed and validated. Urine samples are subjected to deconjugation using β-glucuronidase, followed by a solvent extraction procedure. Compounds are separated on a reverse-phase HPLC column within a 14 min cycle. Low assay limits are required in order to demonstrate prior exposure to SCs. Matrix effects were studied and proved to be significant for selected analytes, and were challenging to circumvent as isotope-labeled internal standards are not available. An elimination profile from a naïve user following a single smoke of “Kronic” was constructed, showing urinary excretion over 2–3 days with peak concentrations of different metabolites 3–16.5 h after smoking. This method has been developed to process several hundred samples within a high-throughput drugs of abuse laboratory, with growing evidence that the use of synthetic cannabinoid blends is common within the Australian workforce.