Screening of Synthetic Cathinones and Metabolites in Dried Blood Spots by UPLC-MS-MS.

After its use for decades in clinical screening, dried blood spots (DBS) have recently received considerable attention for their application in various novel psychoactive substances. The goal of this study was to develop and apply a DBS-based assay for 37 synthetic cathinones and their metabolites. Thirty microliters of whole blood sample after administration was spotted onto Whatman FTA classical cards, dried and extracted, and then analyzed by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS-MS). The samples were chromatographed on a Waters Acquity UPLC®HSS T3 column (1.8 μm, 2.1*100 mm) and then identically packed defender guard cartridges of a Waters Acquity UPLC®HSS T3 column (1.8 μm, 2.1*5 mm, 3/pk). The separation was achieved via solvents of 20 mM ammonium acetate/formic acid 0.1% (A) and acetonitrile (B) at a flow rate of 0.25 mL/min. A tandem MS equipped with positive electrospray ionization mode (ESI+) source was used as the detector. Multiple reaction monitoring (MRM) with the precursor/product ion combinations was used to quantify each analyte. The linear range of synthetic cathinones in the DBS was 2.0-200 ng/mL, and the lowest limit of quantification was 2.0 ng/mL for some synthetic cathinones and 10 ng/mL for others. The precision and accuracy of the results for the validation samples of the synthetic cathinones were within acceptable criteria. Dried blood spots sampling offers the advantages of reduced sample volume and convenient sample storage and shipment. This method can be successfully applied to the quantification of synthetic cathinones.