Solid-phase extraction and GC/MS quantitation of cocaine, ecgonine methyl ester, benzoylecgonine, and cocaethylene from meconium, whole blood, and plasma.

A selective solid-phase extraction technique has been applied to the analysis of cocaine and selected cocaine metabolites in meconium, whole blood, and plasma. This technique uses a mixed-mode Bond Elut Certify column that utilizes the characteristics of hydrophobic and polar interactions and ion exchange chromatography. Following extraction, cocaine, ecgonine methyl ester, benzoylecgonine, and cocaethylene were identified and quantitated using GC/MS. Linear quantitative response curves have been generated for the metabolites over a concentration range of 0-1000 ng/g for meconium and 0-1000 ng/mL for whole blood and plasma. The overall extraction efficiencies, depending on the metabolite, were between 58.1 and 99.7% for meconium, 95.6 and 124.0% for blood, and 86.9 and 128.9% for plasma. Linear regression analyses of the standard curve for the four analytes exhibited correlation coefficients ranging from 0.850 to 0.946 for meconium, 0.939 to 0.993 for whole blood, and 0.981 to 0.996 for plasma. Because of its capability to detect cocaethylene in meconium, blood, and plasma, the procedure can be used to determine if drug exposure occurred during the latter stages of gestation and if it involved only cocaine or a combination of cocaine and ethanol.