LC determination of morphine and morphine glucuronides in human plasma by coulometric and UV detection

A reversed-phase high-performance liquid chromatographic method with coulom etric and UV detection has been developed for the simultaneous determinatio n of morphine, morphine-3-glucuronide and morphine-6-glucuronide. The separ ation was carried out by using a Supelcosil LC-8 DB reversed-phase column a nd 0.1 M potassium dihydrogen phosphate (pH 2.5)-acetonitrile-methanol (94: 5:1 v/v) containing 4 mM pentanesulfonic acid as the mobile phase. The comp ounds were determined simultaneously by coulometry for morphine and with UV detection for morphine-3-glucuronide and morphine-6-glucuronide. Morphine, morphine glucuronides and the internal standard were extracted from human plasma using Bond-Elut C18 (1 ml) solid-phase extraction cartridges. In the case of coulometric detection, the detection limit was 0.5 ng/ml for morph ine; in the case of UV detection the detection limit was 10 ng/ml for morph ine-3-glucuronide and for morphine-6-glucuronide. too. (C) 2001 Elsevier Sc ience B.V. All rights reserved.