A quantitative analytical procedure for the determination of cocaine, benzoylecgonine, cocaethylene, and norco- caine in hair has been developed and validated. The hair samples were washed, incubated, and any drugs present were quantified using mixed-mode solid-phase extraction and liquid chromatography with tandem mass spectro- metric detection in positive atmospheric pressure chemi- cal ionization mode. For confirmation, two transitions were monitored and one ion ratio was determined, which was within 20% of that of the known calibration stan- dards. The monitoring of the qualifying transition and requirement for its presence within a specific ratio to the primary ion limited the sensitivity of the assay, particu- larly for benzoylecgonine; however, the additional confi- dence in the final result as well as forensic defensibility were considered to be of greater importance. Even with simultaneous monitoring, the concentrations proposed by the United States federal guidelines for hair analysis were achieved. The limits of quantitation were 50 pg/mg; the limit of detection was 25 pg/mg. The intra-day precision Determination of Cocaine, Benzoylecgo- nine, Cocaethylene, and Norcocaine in Human Hair Using Solid-Phase Extraction and Liquid Chromatograp
