Simultaneous determination of synthetic cannabinoids in illegal herbal products and blood by LC/TOF-MS, and linear regression analysis of retention time using log Pow

Abstract

A method for the simultaneous determination of 47 synthetic cannabinoids in herbal products and blood (serum and whole blood) by liquid chromatography/time-of-flight mass spectrometry (LC/TOF-MS) was developed. In addition, linear regression analysis of logarithm of retention time and log Pow was conducted to identify unknown synthetic cannabinoids. The target compounds were separated on a reversed-phase Poroshell 120 EC-C18 (100 mm × 4.6 mm I.D, 2.7 µm) column using a mixture of acetonitrile/10 mM ammonium formate buffer solution (70:30) as the mobile phase in the isocratic elution mode. The herbal products were extracted with methanol and the extracts were filtered. The strong linear correlation between log Pow and logarithm of retention time suggests that linear regression analysis would be useful for deducing unknown synthetic cannabinoids in combination with accurate mass measurement by TOF-MS. Blood samples were deproteinized with acetonitrile and subjected to solid-phase dispersive extraction for sample extraction and cleanup. The average recoveries for blood analysis spiked at 10 ng/mL were 61.8% for serum and 61.0% for whole blood. One-way analysis of variance revealed that the mean repeatability value and the mean intermediate precision value for serum were 7.4% and 10.5%, respectively, and those for whole blood were 6.1% and 11.4%, respectively. The developed method was applicable as a screening method for synthetic cannabinoids in illegal herbal products as well as serum and whole blood samples.