An improved method for the determination of ∆9-tetrahydrocannabinol, cannabinol and cannabidiol in hair by liquid chromatography-tandem mass spectrometry

A fast high performance liquid chromatography with tandem mass spectrometry (HPLC-MS/MS) method for assessing < DELTA > 9-tetrahydrocannabinol (< DELTA > 9-THC), cannabidiol (CBD) and cannabinol (CBN) in hair has been developed and validated. Hair samples were oven digested with 2.0 M sodium hydroxide (100 °C, 10 min), and targets were further extracted by liquid-liquid extraction with hexane/ethyl acetate (9:1). A chromatographic run based on a gradient elution (0.1% (v/v) formic acid in acetonitrile and in ultrapure water) was performed in 5 min. The limits of detection were 0.25, 0.21, and 0.22 ng g− 1, for < DELTA > 9-THC, CBN and CBD, respectively. The relative standard deviation of intra- and inter-day precision was lower than 4 and 7%, respectively, and intra- and inter-day analytical recoveries ranged from 95 and 106%, and 93 and 105%, respectively. The method was applied to hair samples collected from proven cannabis abusers.