Emerging Synthetic Cannabinoids: Development and Validation of a Novel Liquid Chromatography Quadrupole Time-of-Flight Mass Spectrometry Assay for Real-Time Detection

Synthetic cannabinoids pose significant threats to public health and safety, as their implications in overdose and adverse events continue to arise in United States and around the world. Synthetic cannabinoids have seen several generations of chemically diverse structural elements, impacting potency and effects. These factors create new analytical challenges for forensic laboratories. This report describes an efficient liquid chromatography/quadrupole time-of-flight mass spectrometry (LC-QTOF-MS) assay for the identification of synthetic cannabinoid parent compounds and metabolites, including real-time identification of emergent compounds, using a SCIEX TripleTOF® 5600+ with non-targeted SWATH® acquisition. Method validation evaluated precision/accuracy, limits of detection, interferences, processed sample stability and carryover, for which 19 parent compounds and 19 metabolites were tested. To demonstrate feasibility, de-identified blood sample extracts were acquired from a large forensic toxicology laboratory and analyzed using the validated LC-QTOF-MS assay. In mid-2018, 200 blood extracts were analyzed, demonstrating a 19% positivity rate with > 94% agreement rate with original testing. In addition, three newly discovered synthetic cannabinoids were identified, including 5F-MDMB-PICA, 4-cyano CUMYL-BUTINACA and 5F-EDMB-PINACA. These synthetic cannabinoids were previously unreported in forensic toxicology casework in the United States. 5F-MDMB-PICA has become the most prevalent synthetic cannabinoid in United States, as of early 2019. These results demonstrate the effectiveness of this assay and workflow in the identification and characterization of synthetic cannabinoids, as well as the usefulness of sample-mining using non-targeted mass acquisition by LC-QTOF-MS for the discovery of NPS. High resolution mass spectrometry should be considered when developing new or novel assays for synthetic cannabinoids.