Symmetry shield and XTerra reversed phase columns in HPLC determination of morphine and its metabolites

A simple HPLC method has been developed for the determination of morphine and its two metabolites, morphine-6-glucuronide and morphine-3-glucuronide in serum. An SPE procedure using OASIS cartridges was recommended for the serum sample preparation. Stationary phases of new generation (Symmetry Shield, XTerra) were tested for the HPLC separation. Mobile phases without any organic modifier and without ion pairs were applied in wide ranges of pH values (Symmetry Shield column pH = 2.5-7.2, XTerra column PH = 2.5-9.5). For higher PH values, very low contents of organic modifier could be used (1, 2%). All analytes were detected by UV detection at 210nm. Detection limits of the assay were 6.9ng/ml for morphine, 2.3ng/ml for M3G and 20.0ng/ml for M6G. The complete SPE-HPLC assay was developed for the therapeutic drug monitoring of morphine, M3G and M6G in cancer patient samples.