Identification and quantification of 35 psychotropic drugs and metabolites in hair by LC-MS/MS: application in forensic toxicology

• Published in: International journal of legal medicine 2015-03, Vol.129 (2), p.259-268
• Main Authors: Maublanc, Julie, Dulaurent, Sylvain, Morichon, Julien, Lachâtre, Gérard, Gaulier, Jean-michel
• Format: Article
• Language: English
• Subjects: Chromatography, High Pressure Liquid; Clonazepam - analogs & derivatives; Clonazepam - analysis; Cocaine; Drugs; Flunitrazepam - analogs & derivatives; Flunitrazepam - analysis; Forensic Medicine; Forensic Toxicology; Hair - chemistry; Humans; Limit of Detection; LSD; Lysergic acid diethylamide; Medical Law; Medicine; Medicine & Public Health; Metabolites; Methadone; Original Article; Psychotropic drugs; Psychotropic Drugs - analysis; Sex crimes; Tandem Mass Spectrometry; Toxicology
• ISSN: 0937-9827; 1437-1596
• DOI: 10.1007/s00414-014-1005-1

Despite a non-invasive sampling, hair samples are generally collected in limited amounts for an obvious esthetic reason. In order to reduce the required quantity of samples, a multianalytes method allowing simultaneous identification and quantification of 35 psychoactive drugs was developed. After incubation of 50 mg of hair in a phosphate buffer pH 5 for one night at room temperature, the substances of interest were extracted by a simple liquid–liquid extraction step, with a dichloromethane/ether mixture (70:30, v/v ). After evaporation under a gentle stream of nitrogen and reconstitution in formate buffer (2 mM, pH 3)/acetonitrile (90:10, v/v ), twenty microliter were injected into the LC-MS/MS system for a chromatographic run of 29 min using an Atlantis T3 column (150 × 2.1 mm, 3 μm) (Waters Corp, Milford, USA) and a gradient mixture of 2 mM, pH 3.0 ammonium formate, and 2 mM, pH 3.0 ammonium formate/acetonitrile. The data acquisition was performed in scheduled MRM mode. Intra- and inter-day precisions, estimated using the coefficient of variation and relative bias, were lower than 20 % for all concentration levels, except for two compounds. The limits of detection and quantification ranged from 0.5 to 10 pg/mg. After complete validation, this method has been successfully used in several forensic cases, three of which are reported.