Development of reference materials for amphetamines in hair

This study presents the development and validation of matrix-based reference materials for the determination of amphetamine-type stimulants (ATS) in human hair samples. Human hair samples without a history of drug abuse were selected and immersed in a drug-dimethyl sulfoxide solution to prepare hair standard substances. The added drugs include six types of amphetamine drugs, namely, amphetamine, methamphetamine, 3,4-methylenedioxy-<i>N</i>-ethylamphetamine, 3,4-methylenedioxymethylamphetamine, triphenylalanine and ephedrine. The soaked hair samples were subjected to treatments such as washing, drying, cutting and homogenization. Using methamphetamine-D₅ as the internal standard, quantitative analysis was carried out by liquid chromatography-tandem mass spectrometry (LC-MS/MS) and gas chromatography-tandem mass spectrometry (GC-MS/MS) in multi-reaction monitoring (MRM) and selective ion monitoring (SIM) modes. Homogeneity tests and uncertainty evaluations were conducted on the prepared hair reference materials. The results show that the concentration range of amphetamine-type drugs in the hair standard substances was (1.32-3.29) ng mg^-1. These matrix matching calibrations address a key gap in forensic toxicology quality assurance, especially in the standardization of hair analysis. The optimized dual-platform method has excellent sensitivity and accuracy (and specificity), laying a solid foundation for the production of reference materials, conforming to the ISO 17034 standard. This work provides an effective framework for improving the reliability of workplace drug testing, postnatal toxicology and longitudinal drug abuse monitoring programs.