High-temperature ultra-performance liquid chromatography coupled to hybrid quadrupole time-of-flight mass spectrometry applied to ibuprofen metabolites in human urine

The application of sub-2 microm porous particle liquid chromatography (LC) operated at elevated temperatures, coupled with time-of-flight mass spectrometry (MS), to the separation and identification of metabolites of ibuprofen present in human urine following oral administrations is illustrated. The LC/MS system generated a high-resolution analytical separation that, with an analysis time of 20 min, provided a peak capacity in the order of ca. 350. Using this system a total of nine glucuronides of the drug and its metabolites were detected, including a number of isomeric acyl glucuronides of ibuprofen itself, a side-chain-oxidized carboxylic acid acyl glucuronide and a number of acyl glucuronides of various hydroxylated metabolites. The identities of the metabolites were confirmed by their accurate mass values and the presence of the common fragment ions from ibuprofen.