P.6.021 Rebound insomnia after abrupt hypnotic withdrawal

A liquid chromatography–tandem mass spectrometry (LC–MSMS) target screening in 50 mg hair was developed and fully validated for 35 analytes (Δ9-tetrahidrocannabinol (THC), morphine, 6-acetylmorphine, codeine, methadone, fentanyl, amphetamine, methamphetamine, 3,4-methylenedioxyamphetamine, 3,4-methylenedioxymethamphetamine, benzoylecgonine, cocaine, lysergic acid diethylamide, ketamine, scopolamine, alprazolam, bromazepam, clonazepam, diazepam, flunitrazepam, 7-aminoflunitrazepam, lorazepam, lormetazepam, nordiazepam, oxazepam, tetrazepam, triazolam, zolpidem, zopiclone, amitriptyline, citalopram, clomipramine, fluoxetine, paroxetine and venlafaxine). Hair decontamination was performed with dichloromethane, and incubation in 2 mL of acetonitrile at 50 °C overnight. Extraction procedure was performed in 2 steps, first liquid–liquid extraction, hexane:ethyl acetate (55:45, v:v) at pH 9, followed by solid-phase extraction (Strata-X cartridges). Chromatographic separation was performed in AtlantisT3 (2.1 mm × 100 mm, 3 μm) column, acetonitrile and ammonium formate pH 3 as mobile phase, and 32 min total run time. One transition per analyte was monitored in MRM mode. To confirm a positive result, a second injection monitoring 2 transitions was performed. The method was specific (no endogenous interferences, n = 9); LOD was 0.2–50 pg/mg and LOQ 0.5–100 pg/mg; linearity ranged from 0.5–100 to 2000–20,000 pg/mg; imprecision <15%; analytical recovery 85–115%; extraction efficiency 4.1–85.6%; and process efficiency 2.5–207.7%; 27 analytes showed ion suppression (up to −86.2%), 4 ion enhancement (up to 647.1%), and 4 no matrix effect; compounds showed good stability 24–48 h in autosampler. The method was applied to 17 forensic cases. In conclusion, a sensitive and specific target screening of 35 analytes in 50 mg hair, including drugs of abuse (THC, cocaine, opiates, amphetamines) and medicines (benzodiazepines, antidepressants) was developed and validated, achieving lower cut-offs than Society of Hair Testing recommendations.