Quantitation of Morphine, Codeine, Hydrocodone, Hydromorphone, Oxycodone, Oxymorphone, and 6-Monoace

Opiates and opioids currently rank among the most commonly prescribed pain medications. We describe two liquid chromatography tandem mass spectrometry (LC-MS-MS) methods for the quantification of morphine, codeine, hydrocodone, hydromorphone, oxycodone, oxymorphone, and 6-monoacetylmorphine (6-MAM). In the first, urine samples are pretreated by acidifying with sodium acetate containing appropriate deuterated internal standards and hydrolyzed with β-glucuronidase. Samples are cooled, diluted with water, vortexed, centrifuged, and a portion is transferred to an autosampler vial for analysis. The second method allows for the measurement of the compounds in blood, serum, or plasma specimens. Analysis of these samples involves pretreatment with acetonitrile containing deuterated internal standards to deproteinize the sample, which is subsequently vortexed and centrifuged. A portion of the organic layer is transferred to a clean test tube, dried under nitrogen, and reconstituted with water for analysis. Quantitation of analytes is accomplished using a commercially available single-point calibrator (urine samples) or an in-house prepared six-point standard curve (blood samples).