Simultaneous quantification of opiates, cocaine, and metabolites in hair by LC-APCI-MS/MS

A quantitative LC-APCI-MS/MS method for simultaneous measurement of opiates, cocaine, and metabolites in hair was developed and validated. Cocaine and opiates were extracted from pulverized hair via sonication in methanol at 37 degreesC for 3 h. Samples were cleaned up using solid-phase extraction. LC separation was achieved in 20 min with identification and quantification by selected reaction monitoring. Calibration by linear regression analysis utilized deuterated internal standards and a weighting factor of 1/x (R-2 > 0.998). limits of quantification (LOQ) ranged from 17 to 50 pg/mg for cocaine and metabolites and were 83 pg/mg for opiates. Standard curves were linear from the LOQ to 5000 pg/mg for cocaine and metabolites, except benzoylecgonine (2500 pg/mg). Opiate standard curves were linear from the LOQ to 12500 pg/mg. Accuracy ranged from 84 to 115% for all quantitative analytes. Precision, % relative standard deviation, was less than 11.0% for all analytes. Methanolic sonication produced less than 5% hydrolysis of cocaine and 6-acetylmorphine. The method should be useful for studying cocaine and opiate distribution into hair.