Simultaneous Quantitative Determination of Amphetamines, Opiates, Ketamine, Cocaine and Metabolites in Human Hair: Application to Forensic Cases of Drug Abuse

A method using liquid chromatography-tandem mass spectrometry (LC-MS/MS) to simultaneously quantify amphetamines, opiates, ketamine, cocaine, and metabolites in human hair is described. Hair samples (50 mg) were extracted with methanol utilizing cryogenic grinding. Calibration curves for all the analytes were established in the concentration range 0.05-10 ng/mg. The recoveries were above 72%, except for AMP at the limit of quantification (LOQ), which was 48%. The accuracies were within +/- 20% at the LOQ (0.05 ng/mg) and between -11% and 13.3% at 0.3 and 9.5 ng/mg, respectively. The intraday and interday precisions were within 19.6% and 19.8%, respectively. A proficiency test was applied to the validated method with z-scores within +/- 2, demonstrating the accuracy of the method for the determination of drugs of abuse in the hair of individuals suspected of abusing drugs. The hair concentration ranges, means, and medians are summarized for abused drugs in 158 authentic cases.