Development and practical application of accelerated solvent extraction for the isolation of cocaine/crack biomarkers in meconium samples

A method using accelerated solvent extraction (ASE) for the isolation of cocaine/crack biomarkers in meconium samples, followed by solid phase extraction (SPE) and the simultaneous quantification by gas chromatography–mass spectrometry (GC–MS) was developed and validated. Initially, meconium samples were submitted to an ASE procedure, which was followed by SPE with Bond Elut Certify I cartridges. The analytes were derivatizated with PFP/PFPA and analyzed by GC–MS. The limits of detection (LOD) were between 11 and 17 ng/g for all analytes. The limits of quantification (LOQ) were 30 ng/g for anhydroecgonine methyl ester, and 20 ng/g for cocaine, benzoylecgonine, ecgonine methyl ester and cocaethylene. Linearity ranged from the LOQ to 1500 ng/g for all analytes, with a coefficients of determination greater than 0.991, except for m-hydroxybenzoylecgonine, which was only qualitatively detected. Precision and accuracy were evaluated at three concentration levels. For all analytes, inter-assay precision ranged from 3.2 to 18.1%, and intra-assay precision did not exceed 12.7%. The accuracy results were between 84.5 and 114.2% and the average recovery ranged from 17 to 84%. The method was applied to 342 meconium samples randomly collected in the University Hospital—University of São Paulo (HU—USP), Brazil. Cocaine biomarkers were detected in 19 samples, which represent 5.6% of exposure prevalence. Significantly lower birth weight, length and head circumference were found for the exposed newborns compared with the non-exposed group. This is the first report in which ASE was used as a sample preparation technique to extract cocaine biomarkers from a complex biological matrix such as meconium samples. The advantages of the developed method are the smaller demand for organic solvents and the minor sample handling, which allows a faster and accurate procedure, appropriate to confirm fetal exposure to cocaine/crack.