Abstract
This paper describes a gas chromatography‐mass spectrometry method for the simultaneous detection of opiates, cocaine, and benzoylecgonine from human hair samples. Conditioning samples were extracted with Waters Oasis HLB (hydrophilic‐lipophilic balance) cartridges. The detector response was linear for the drugs studied over the range 0.5–20 ng/mg. The limits of quantitation and detection were found to be acceptable. Intra‐ and interbatch coefficients of variation oscillated between 0.2 and 17.9%, and mean relative errors were in the range of 0.04–18.2%. The recoveries were higher than 66.7% in all cases. Finally, the method was applied to 20 hair samples from drug users, obtaining positive results in all cases.