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 µm 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. Copyright © 2007 John Wiley & Sons, Ltd.