UHPLC-MS/MS method for simultaneously detecting 16 tryptamines and their metabolites in human hair and applications to real forensics cases.

• A rapid UHPLC-MS/MS method for the screening of 16 tryptamines in hair is reported. • LODs ranged between 0.1 and 20 pg/mg and LLOQs ranged from 3 to 50 pg/mg. • The method was applied to 191 hair samples, 77 of which were 5-MeO-DiPT-positive. • 5-MeO-DiPT was determined to be the main tryptamine of abuse found in hair samples. • Most users were aged between 30 and 35. Tryptamines are hallucinogenic substances many of which have appeared recently as novel psychoactive substances (NPS). Herein, we describe the establishment of a rapid UHPLC-MS/MS quantitative method for the targeted screening of 16 tryptamines of abuse in hair. Twenty milligram pieces of hair were pulverized below 4 °C in 0.5 mL of deionized water containing 0.1% formic acid and an internal standard (2 ng/mL psilocin-d 10 and psilocybin-d 4). After subsequent centrifugation, 5 μL of the supernatant was injected into a LC–MS/MS system fitted with a Waters Acquity UPLC HSS T 3 column (100 mm × 2.1 mm, 1.8 μm). The column was gradient eluted at 0.3 mL/min with mobile phases composed of 20 mmol/L ammonium acetate, 5% acetonitrile, and 0.1% formic acid in water (solvent A) and acetonitrile (solvent B). Limits of detection ranged between 0.1 and 20 pg/mg, with limits of quantitation ranging from 3 to 50 pg/mg. The calibration curves for all analytes were linear (r > 0.992). Accuracies varied between 91% and 114%, with intraday precision RSDs < 14% and interday precision RSDs of between 1.3% and 14%. The recoveries of all tryptamines were in the 85–115% range, with the matrix effect ranging from 95% to 112%. The validated method was successfully used to analyse 191 hair samples from suspected tryptamine users, 77 of which were 5-MeO-DiPT-positive, while the 16 tryptamines and their metabolites were not detected in the remaining 114 hair samples. 5-MeO-DiPT and its 5-MeO-NiPT, 5-OH-DiPT, and 4-OH-DiPT metabolites were concurrently detected in 34 hair samples. 5-MeO-DiPT, as the parent drug, was the parent substance found in the hair samples. [ABSTRACT FROM AUTHOR]