Application of a validated high-performance liquid chromatography–mass spectrometry assay to the analysis of m- and p-hydroxybenzoylecgonine in meconium

A high-performance liquid chromatography (HPLC)–mass spectrometry (MS) assay, already validated for opiates and cocaine in meconium, has been re-applied for determination of m- and p-hydroxybenzoylecgonine, using nalorphine as the internal standard. Methodology included an initial extraction from the matrix by methanol and then a solid-phase extraction (SPE). A reversed-phase chromatography was used with a gradient of 1% acetic acid–acetonitrile coupled to atmospheric pressure ionization electrospray–mass spectrometry single ion monitoring mode. This method, validated in the range 0.005–1.00 μg analytes/g meconium, proved useful to identify and quantify these two metabolites in meconium samples, already tested for the presence of cocaine, benzoylecgonine and cocaethylene. A positivity of range of concentrations varied between 0.007 and 0.338 μg/g, confirming the importance of these two hydroxylated derivatives to monitor fetal exposure to cocaine.