Simple screening procedure for 72 synthetic cannabinoids in whole blood by liquid chromatography–tandem mass spectrometry

Katarzyna Ambroziak, Piotr Adamowicz

In recent years, many synthetic cannabinoids (SCs) have appeared on the drug market. Despite the increasing number of SCs, there are few comprehensive screening methods for their detection in biological specimens. In this context, the purpose of this study was to develop a fast and simple liquid chromatography-tandem mass spectrometry screening procedure for detection and identification of SCs in whole blood. The elaborated qualitative screening method allows the simultaneous detection and identification of 72 compounds from different chemical groups: naphthoylindoles, naphthoylindazoles, benzoylindoles, phenylacetylindoles, tetramethylcyclopropylindoles, indole-3-carboxylic acid esters, indole-3-carboxylic acid amides, indazole-3-carboxylic acid amides, and others. Whole-blood samples (0.2 mL) were precipitated with acetonitrile (0.6 mL). The separation was achieved with the gradient of the mobile phase composition (0.1% formic acid in acetonitrile and 0.1% formic acid in water) and the gradient of the flow rate (0.5-0.8 mL/min) in 16 min. Detection of all compounds was based on dynamic multiple reaction monitoring. Mass spectrometer parameters for all compounds were presented. All of the compounds were well-separated by their retention times and/or transitions. The limits of detection (LODs) for 50 compounds were in the range 0.01-0.48 ng/mL. Estimated LODs make this assay suitable for the analysis of biological material. The procedure can be easily expanded for more substances, which is an indispensable advantage in the dynamically developing drug market. It can have wide application in various analytical forensic and clinical laboratories.