Determination of cannabinoid and synthetic cannabinoid metabolites in wastewater by liquid-liquid extraction and ultra-high performance supercritical fluid chromatography-tandem mass spectrometry.

For the first time, ultra-high performance supercritical fluid chromatography (UHPSFC) coupled to tandem mass spectrometry has been used to determine cannabinoid and synthetic cannabinoid residues in wastewater. Combined with a downscaled version of the classic liquid-liquid extraction, the proposed method allows for the quantification of Δ9-tetrahydrocannabinol, three of its major metabolites (the monohydroxylated, the dehydroxylated, and the carboxylated species) and four synthetic cannabinoid metabolites (from the JWH-series) at low ng L levels. Limits of quantification are in the 1-59 ng L range, with recovery between 62 and 122% in ultrapure water and between 59 and 138% in wastewater. The applicability of the developed methodology was confirmed by the analysis of real wastewater, where cannabis metabolites could be positively quantified in all the samples analyzed. It is, therefore, a fast and simple alternative to common solid-phase extraction-liquid chromatography-mass spectrometry procedures for the determination of these low polar substances in water. Copyright © 2017 John Wiley & Sons, Ltd.