High-throughput screening for drugs of abuse and pharmaceutical drugs in hair by liquid-chromatography-high resolution mass spectrometry (LC-HRMS)

A liquid chromatography–high resolution mass spectrometry (LC-HRMS) method for the simultaneous screening in hair samples of drugs of abuse and medicaments was developed. Target analytes screened using a single extraction and analytical run were opiates, cocaine, amphetamines and amphetamine-like substances, ketamine and analogues, cannabinoids, both natural and synthetic, cathinones, piperazines, ephedrines and others new psychoactive substances not pertaining to these classes; pharmaceutical drugs such as antipsychotics, antiepileptics, antidepressants, benzodiazepines and analogues, anorectics, stimulants, drugs for the erectile dysfunction. The multiresidual method involved methanolic incubation of 30 mg of decontaminated hair and analysis of the extract in HPLC using a C18 column. The mass detector, a benchtop Orbitrap Exactive, with nominal resolving power of 100,000, operated in full scan mode in positive ESI. Analytes were identified by exact mass, correspondence of isotopic cluster and retention times using a home-made database. The database contained the protonated exact masses of each monoisotopic compound, the retention time and the molecular formula of each studied analyte. At the moment the database contains 177 analytes. The screening method was validated for selectivity, limit of detection (LOD), matrix effect and carryover. The limits of detection obtained varied from 2 to 30 pg/mg, and the matrix effect was negligible. This method was then applied to three hundred authentic samples, resulting in the identification of various drugs of abuse and therapeutic drugs. The analyte identity was subsequently confirmed by in-source fragmentation. Thanks to the scan acquisition, this method also enables retrospective re-analysis of the acquired datafile in case a further analyte needs to be screened.