A selective assay of morphine-3-glucuronide (M3G), morphine-6-glucuronide (M6G), morphine, codeine, codeine-6-glucuronide (C6G) and 6-monoacetylmorphine (6-MAM) based on liquid chromatography atmospheric pressure chemical ionization mass spectrometry (LC-APCI-MS) is described. The drugs were extracted from serum, autopsy blood, urine, cerebrospinal fluid or vitreous humor using C-18 solid-phase extraction cartridges and subjected to LC-APCI-MS analysis. The separation was performed on an ODS column in acetonitrile-50 mM ammonium formate buffer, pH 3.0 (5:95), using a flow-rate gradient from 0.6 to 1.1 ml/min (total analysis time was 17 min). The quantitative analysis was done using deuterated analogues of each compound. Selected-ion monitoring detection was applied: m/z 286 (for morphine, M3G-aglycone and M6G-aglycone), 289 (for morphine-d(3), M3G-d(3)-aglycone and M6G-d(3)-aglycone), 300 (for codeine and C6G-aglycone), 303 (for C6G-d(3)-aglycone), 306 (for codeine-d(6)), 328 (for 6-MAM), 334 (for 6-MAM-d(6)), 462 (for M3G and M6G), 465 (for M3G-d(3) and M6G-d(3)), 476 (for C6G) and 379 (for C6G-d(3)). The limits of quantitation were: 1 mu g/l for morphine, 2 mu g/l for 6-MAM, 5 mu g/l for M3G, M6G and codeine and 200 mu g/l for C6G. The recovery ranged from 85 to 98% for each analyte. The method appeared very selective and may be used for the routine determination of opiates in body fluids of heroin abusers and patients treated with opiates. (C) 1997 Elsevier Science B.V.
