Simultaneous quantification of opiates, amphetamines, cocaine and metabolites and diazepam and metabolite in a single hair sample using GC–MS

A method is described for the simultaneous identification and quantification of opiates, amphetamines, cocainics, diazepam and nordiazepam from one hair extract (typically 10–50 mg hair). After decontamination by washing with shampoo, dichloromethane, isopropanol and acetone, drugs were extracted using 0.1 M HCl followed by SPE clean-up using mixed-mode extraction cartridges. The SPE extracts were submitted to a two-step derivatisation using MBTFA and MSTFA + 1% TCMS and analysis was performed by GC–MS using both SIM and scan modes. Four deuterated standards were used to monitor 14 compounds. The limit of quantification was the total drug detected from the sample. This was 5 ng for amphetamines and 10 ng for remaining drugs which is equivalent to 0.1 and 0.2 ng/mg from a 50 mg sample.Standard curves for the range 5–400 ng total drug concentration for all drugs had regression coefficients greater than 0.98. An authentic hair sample was used to validate the method and gave R.S.D.s <25% for both inter and intra-day reproducibility.The results of the analysis of hair taken from four patients attending a drug treatment clinic and six hair samples including head hair, pubic hair, axial hair and beard taken at post-mortem are presented.