GC-MS determination of heroin metabolites in meconium: evaluation of four solid-phase extraction cartridges

A procedure for extraction of heroin and metabolites for gas chromatography-mass spectrometry (GC-MS) analysis of meconium specimens that would allow detection of these analytes at low levels was needed. Solid-phase extraction (SPE) cartridges were therefore evaluated for their effectiveness in sample preparation. Four different types of commercially available extraction cartridges were used. Heroin, 6-monoacetylmorphine (6-MAM), morphine, and codeine were extracted from meconium samples using these SPE cartridges and then simultaneously analyzed using GC-MS. In each case, the extraction efficiency, linearity range, limit of detection (LOD), limit of quantitation (LOQ), between-run precision, and within-run precision were determined. Although satisfactory results were obtained with the four different types of SPE cartridges, best overall performance was observed using Clean Screen columns following the procedures outlined here. LODs as low as 20 ng/g for codeine, 10 ng/g for morphine, and 2.5 ng/g for 6-MAM were obtained, and LOQs as low as 20 ng/g for codeine, 10 ng/g for morphine, and 5 ng/g for 6-MAM were obtained. In all cases linearities were observed (r = > 0.99) for codeine, morphine, and 6-MAM over a wide concentration range (100-2000, 100-2000, and 5-100, respectively). At 50 ng/g codeine and morphine and 10 ng/g 6-MAM, the precision of analysis using these cartridges showed coefficients of variation ranging from 4.75% to 15.5%.