Solid-phase extraction-liquid chromatography-tandem mass spectrometry method for the qualitative analysis of 61 synthetic cannabinoid metabolites in urine.

This article comprises the development and validation of a protocol for the qualitative analysis of 61 phase I synthetic cannabinoid metabolites in urine originating from 29 synthetic cannabinoids, combining solid-phase extraction with a reversed phase silica-based sorbent (phenyl) with liquid chromatography-tandem mass spectrometry. Validation was performed according to the guidelines of the German Society of Toxicological and Forensic Chemistry. Sufficient chromatographic separation was achieved within a total runtime of 12.3 min. Validation included specificity and selectivity, limits of detection, recovery and matrix effects as well as auto-sampler stability of processed urine samples. Limits of detection ranged between 0.025 ng/mL and 0.5 ng/mL in urine. Recovery ranged between 43% and 97%, with only two analytes exhibiting recoveries below 50%. However, for those two analytes, the limits of detection were 0.05 ng/mL in urine. In addition, matrix effects between 81% and 185% were determined, whereby matrix effects over 125% were observed for 10 non-'first generation' synthetic cannabinoid metabolites. The developed method enables the rapid and sensitive detection of synthetic cannabinoid metabolites in urine, complementing the spectrum of existing analytical tools in forensic case work. Finally, application to 61 urine samples from both routine and autopsy case work yielded one urine sample tested positive for ADB-PINACA N-pentanoic acid.