Qualitative and quantitative analysis of synthetic cannabinoids in e-liquids by pyrolysis-gas chromatography/mass spectrometry

Synthetic cannabinoids (SCs) are a series of synthetic substances that mimic the effects of natural cannabis and cause more serious toxicity and public safety issues. SCs, with a wide variety and fast update rate have become the most abused family of new psychoactive substances. A pyrolysis-gas chromatography/mass spectrometry method has been developed to qualitatively and quantitatively analyze SCs in e-liquids using pyrolysis products as analytical targets, which can effectively expand the detection range of SCs. In qualitative analysis, diluted eliquids were pyrolyzed in the microfurnace at 800, 600, and 300 degree celsius, respectively, followed by separation and analysis through gas chromatography/mass spectrometry. SCs in the e-liquids were determined by both shared and characteristic pyrolysis products combined with the EI mass spectrometry of their parent compounds. ADBBUTINACA and 5F-MDMB-PICA were successfully identified in five e-liquid samples seized by local police. Furthermore, five popular SCs in the illegal market, ADB-BUTINACA, 4F-ABUTINACA, 4CN-CUMYL-BUTINACA, 4F-MDMB-BICA, and 5F-MDMB-PICA, were quantitatively analyzed based on their characteristic pyrolysis products as the analysis targets. The results indicated that the linear range of ADB-BUTINACA was 2-200 mu g/mL, while those of 4F-ABUTINACA and 4CN-CUMYL-BUTINACA were 1-200 mu g/mL. For 4F-MDMB-BICA and 5FMDMB-PICA, the linear range was 5-500 mu g/mL. The linear correlation coefficients of determination of five SCs were greater than 0.994. The limit of detection (S/N=3) for five SCs was 0.25-2.50 mu g/mL, and the limit of quantification (S/N=10) was 0.50-5.00 mu g/mL. This quantitative method was applied to five positive samples in real cases. The results showed that the concentrations of ADB-BUTIANCA and 5F-MDMB-PICA in the positive samples were 751.32-4810.10 mu g/mL and 1109.41 mu g/mL, respectively. The current research provides a validated pyrolysis-gas chromatography/mass spectrometry method, with simple pre-treatment, fast operation and wide screening range, to accurately identify and quantify SCs in e-liquid samples without reference materials.