Analysis of synthetic cannabinoids in herbal blends by means of nano-liquid chromatography

In this study, a rapid and simultaneous separation of 12 synthetic cannabinoids and 9 -tetrahydrocannabinol (9 -THC) in herbal blends was obtained by means of nano-liquid chromatography (nano-LC). The nano-LC experiments were performed in a 100 m i.d. capillary column packed with Cogent ® bidentate C18silica particles for 25.0 cm. All compounds were resolved using an isocratic elution mode in less than 30 min. A mobile phase containing ACN/MeOH/H2O/formic acid 69/5/25/1 (v/v/v/v) was employed for the chromatographic separation. The developed analytical method was validated in terms of precision, linearity, sensitivity and accuracy. Under optimal nano-LC-UV conditions, the resulting RSD percentages for intra-day and inter-day repeatability, related to retention time and peak area, were below 2.98 and 6.40%, respectively. Limits of detection and quantification were 0.2 and 0.5 g/mL, respectively, for all the studied compounds. Linearity was assessed in the concentration range of interest for all ana-lytes with determination coefficients r 2>= 0.9975. The method was then applied to the determination of synthetic cannabinoids in herbal blends. Quantitative analyses of the cannabimimetic compounds in six products showed that there was a wide difference in the concentration of the studied compounds among different products. Further, the nano-LC system was coupled with a mass spectrometer measuring the MS and MS-MS spectra to unequivocally identify the cannabinoids present in smoking mixtures.