Validation of a Solild Phase Extraction Procedure for the Gc-MS Identification and Quantitation of Cocaine and Three Metabolites in Blood, Urine, and Milk

A simple and widely used solid-phase extraction procedure (United Chemical Technologies Method Handbook) was applied for the GC-MS identification and quantitation of cocaine (COC), benzoylecgonine (BE), cocaethylene (COCE), and m-hydroxy- benzoylecgonine (HBE) in blood, urine, and milk. The method which utilizes BSTFA as a derivatizing agent yielded abundant diagnostic ions with high m/z values. Linear quantitative response curves were generated for the analytes of interest over a concentration range of 5–1000 ng/mL. Linear regression analyses of the standard curve in the three specimen types exhibited correlation coefficients ranging from 0.997 to 1.000. The LOD values for COC, COCE, and derivatives of BE, and HBE in the three specimen types ranged from 2.5 to 5.0 ng/mL. The LOQ values, however, ranged from 5.0 to 10.0 ng/mL. Intra-assay and inter-assay precision studies reflected a high level of reliability and reproducibility of the method. The applicability of the method for the detection and quantitation of COC, BE, COCE, and HBE was demonstrated successfully in human blood and urine samples, as well as blood samples obtained from cocaine-treated (subcutaneously) rats.