An Improved GC–MS/MS Method for a Fast Multidrug Analysis in Hair

ABSTRACT This study presents the development and validation of a drug testing method in hair, employing a semi‐automated sample preparation procedure and gas chromatography–tandem mass spectrometry (GC–MS/MS) for simultaneous multidrug analysis in hair. The method aims to detect and quantify multiple drugs in hair, including amphetamine, methamphetamine, 3,4‐methylenedioxyamphetamine, 3,4‐methylenedioxymethamphetamine, ketamine, norketamine, cocaine, benzoylecgonine, morphine, codeine and 6‐monoacetylmorphine, using a comprehensive procedure involving decontamination, pulverization, clean‐up using supported‐liquid extraction (SLE) and a two‐step derivatization process. The method validation included specificity, linearity, limit of detection (LOD), limit of quantification (LOQ), precision, accuracy, carryover, robustness and stability. The results indicate a linearity range of 0.1–5 ng/mg for all drugs except methamphetamine, which has a linearity range of 0.2–5 ng/mg. The accuracy and precision of the method are within ±20%, with the LOQ at 0.2 ng/mg for methamphetamine, 0.1 ng/mg for amphetamine and MDMA and 0.05 ng/mg for the rest of the drugs. The LODs were found to be 0.1 ng/mg for methamphetamine, 0.05 ng/mg for amphetamine and MDMA and 0.025 ng/mg for other drugs. This method has demonstrated its accuracy by comparing the quantitative test results with the expected results, using hair samples from the proficiency test service providers. This test method offers efficient testing of multiple drugs in a single analysis, significantly improves the hair analysis workflow in a routine testing laboratory by reducing turnaround time and the amount of hair sample required.