Validation of an HPLC–HR-MS Method for the Determination and Quantification of Six Drugs (Morphine, Codeine, Methadone, Alprazolam, Clonazepam and Quetiapine) in Nails.

This article focuses on the development and validation of a sensitive analytical method for the simultaneous extraction and quantification of six drugs—three narcotics (morphine, codeine, methadone), two benzodiazepines (clonazepam, alprazolam), and one antipsychotic (quetiapine)—from human nail matrices using ultra-high-performance liquid chromatography coupled with high-resolution mass spectrometry (UHPLC–HR-MS). The method, validated according to the Scientific Working Group for Forensic Toxicology (SWGTOX) standards, demonstrated high sensitivity, accuracy, and precision, with successful application to authentic postmortem and living donor nail samples. Nails, as keratinized matrices, offer a non-invasive, stable, and long-term record of substance intake, making them valuable in forensic toxicology, especially when conventional matrices like blood or urine are unavailable or limited. The study highlights the potential of this UHPLC–HR-MS method for forensic investigations, drug monitoring, and occupational exposure assessments.