Development and validation of a liquid chromatography mass spectrometry assay for the simultaneous quantification of methadone, cocaine, opiates and metabolites in human umbilical cord

A liquid chromatography mass spectrometric selected reaction monitoring mode (SRM) method for methadone, 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP), cocaine, benzoylecgonine (BE), 6-acetylmorphine, morphine and codeine quantification in human umbilical cord was developed and fully validated. Analytes were extracted from homogenized tissue (1 g) by solid phase extraction. Linearity was 2.5–500 ng/g, except for methadone (10–2000 ng/g). Method imprecision was <12.7%CV with analytical recovery 85.9–112.7%, extraction efficiency >59.2%, matrix effect 4.5–39.5%, process efficiency 48.6–92.6% and stability >84.6%. Analysis of an umbilical cord following controlled methadone administration and illicit drug use contained in ng/g, 40.3 morphine, 3.6 codeine, 442 BE, 186 methadone and 45.9 EDDP.