Isolation and quantification of synthetic cannabinoid receptor agonists in human urine using membrane-assisted solvent extraction followed by liquid chromatography-tandem mass spectrometry

• Published in: Analytical methods 2023-01, Vol.15 (3), p.333-342
• Main Authors: Suárez-Oubiña, Cristian, Álvarez-Freire, Iván, Cabarcos, Pamela, Bermejo, Ana María, Bermejo-Barrera, Pilar, Moreda-Piñeiro, Antonio
• Format: Article
• Language: English
• Subjects: Cannabinoid Receptor Agonists; Cannabinoid receptors; Cannabinoids - urine; Chromatography; Chromatography, Liquid - methods; Forensic science; Global marketing; Hexanes; Human wastes; Humans; Liquid chromatography; Mass spectrometry; Mass spectroscopy; Membranes; n-Hexane; Polypropylene; Room temperature; Scientific imaging; Solvent extraction; Solvent extraction processes; Solvents; Spectroscopy; Tandem Mass Spectrometry - methods; Urine
• ISSN: 1759-9660; 1759-9679
• DOI: 10.1039/d2ay01491b

The global market for new psychoactive substances (NPSs) continues to expand, and the range of drugs available on the market has probably never been wider. Synthetic cannabinoids (SCRAs) constitute the largest family of NPSs, and they go unnoticed during illicit drug market control and during routine toxicological-forensic analysis. Membrane-assisted solvent extraction (MASE) has been a novelty proposed for the simultaneous extraction of SCRAs, and urine has been selected as a model forensic-clinical sample. Isolated SCRAs were further determined by liquid chromatography-tandem mass spectrometry (LC-MS/MS). An optimised sample pre-treatment procedure consists of using 400 μL of n -hexane as an extraction phase placed inside a polypropylene (PP) membrane, adjusting the donor phase (urine) at a pH value of 5.9. Extraction was assisted by mechanical (orbital-horizontal) stirring in a temperature-controlled chamber at room temperature for 20 min. n -Hexane extracts were evaporated to dryness and re-suspended in 100 μL of mobile phase, which leads to a pre-concentration factor of 50. Method validation showed analytical recoveries higher than 80% for most SCRAs and repeatability (inter-day and intra-day assays) with RSD values lower than 20%. The proposed method was found to be selective and sensitive and limits of quantification (LOQs) between 0.10 and 1.0 μg L −1 were achieved. Membrane assisted solvent extraction (MASE) is an appealing environmental-friendly pre-treatment for isolating trace targets. MASE applicability in the forensic laboratory is demonstrated by assessing synthetic cannabinoid receptor agonists in urine.