Photolysis of NSAIDS. I. Photodegradation products of carprofen determined by LC-ESI-MS

Ming Thau Sheu, Hsiu O. Ho, Po Yu Wang, Yi Bo Liou, An-Bang Wu

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11 Citations (Scopus)


A solution of carprofen in methanol at a concentration of 2.74 × 10-2 mg/mL is subjected to photoirradiation using a Hanovia 200-W high-pressure Hg lamp for 9 h. In total, seven photodegradation products are separated, and their quasimolecular ions are subsequently determined online using a liquid chromatography (LC)-electrospray ionization (ESI)-mass spectrometry (MS) method. The high-performance LC consists of an Inertsil 5 ODS-80A (2.1- × 150-mm) column. The mobile phase is initially CH3CN. NH4OAc (20mM in de-ionized H2O) is 43:57 (v/v), and after 14 min it is CH3CN. NH4OAc (20mM in de-ionized H2O) is 54: 46 (v/v). The UV detector was set at 260 nm. The parameters of LC-MS for mass determination involves an atmospheric pressure ionization electron spray interface with a negative mode of polarity (ESI-). The chemical structures of the degradants are elucidated based on the mass-to-charge ratio of the quasimolecular ions and the molecular weight changes by comparison with the parent drug (carprofen). The degradation proceeds via an initial dechlorination. A dechlorination or esterification reaction is competed with decarboxylation. This finding is in accordance with our previously reported result of first order photodecomposition kinetics for carprofen.

Original languageEnglish
Pages (from-to)200-204
Number of pages5
JournalJournal of Chromatographic Science
Issue number4
Publication statusPublished - Apr 2003

ASJC Scopus subject areas

  • Analytical Chemistry


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