An LC–MS/MS method for the simultaneous determination of 12 psychotropic drugs and metabolites in hair: Identification of acute quetiapine poisoning using hair root

•A LC–MS/MS method for determination of 12 psychotropic drugs in hair is developed.•Quetiapine and its metabolite were detected in hair root 5 min post administration.•Higher quetiapine levels occurred in black hair root than that of other colors.•Hair root may be a good specimen for proving acute quetiapine poisoning. A rapid, sensitive liquid chromatography-tandem mass spectrometry (LC–MS/MS) method for the determination and quantification of 12 psychotropic drugs and metabolites in hair was developed and validated. After freeze grinding with methanol, the supernatant was determined by LC–MS/MS using an Allure PFPPropyl column (100 × 2.1 mm, 5 μm) with a gradient elution of acetonitrile and 10 mmol/L ammonium acetate with 0.1% formic acid, and in the subsequent analysis using multiple reaction monitoring (MRM) mode, two ion transitions were monitored for each analyte. The limits of detection ranged from 0.002 to 0.05 ng/mg, and the limits of quantitation were in the range of 0.005–0.1 ng/mg. Good linearity (r > 0.995) was observed for all analytes over the linear range. Acceptable intraday and interday precision (RSD ≤ 20%) and accuracy (85.3%–112.9%) were achieved. This method of detection was applied to the analysis of guinea pig hair roots after a single dose of quetiapine. Quetiapine and 7-hydroxyquetiapine were both detected in guinea pig hair roots from 5 min post administration. The concentration of quetiapine (10.3–1733.8 ng/mg) was much higher than that of 7-hydroxyquetiapine (0.1–40.6 ng/mg) in the hair roots of guinea pigs, and higher concentrations of quetiapine and 7-hydroxyquetiapine occurred in black hair root than in that of white and brown. The animal experiment demonstrated that hair roots may be a good specimen for proving acute quetiapine poisoning when other biological matrices are not available.