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Identification of phase I and phase II metabolites of benfluron and dimefluron in rat urine using high‐performance liquid chromatography/tandem mass spectrometry
Author(s) -
Jirásko Robert,
Holčapek Michal,
Nobilis Milan
Publication year - 2011
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.5097
Subject(s) - chemistry , chromatography , liquid chromatography–mass spectrometry , tandem mass spectrometry , mass spectrometry , urine , tandem , phase (matter) , high performance liquid chromatography , biochemistry , organic chemistry , materials science , composite material
Biotransformation products of two potential antineoplastic agents, benfluron and dimefluron, are characterized using our integrated approach based on the combination of high‐performance liquid chromatography (HPLC) separation of phase I and phase II metabolites followed by photodiode‐array UV detection and electrospray ionization tandem mass spectrometry (MS/MS). High mass accuracy measurement allows confirmation of an elemental composition and metabolic reactions according to exact mass defects. The combination of different HPLC/MS/MS scans, such as reconstructed ion current chromatograms, constant neutral loss chromatograms or exact mass filtration, helps the unambiguous detection of low abundance metabolites. The arene oxidation, N‐oxidation, N‐demethylation, O‐demethylation, carbonyl reduction, glucuronidation and sulfation are typical mechanisms of the metabolite formation. The interpretation of their tandem mass spectra enables the distinction of demethylation position (N‐ vs. O‐) as well as to differentiate N‐oxidation from arene oxidation for both phase I and phase II metabolites. Two metabolic pathways are rather unusual for rat samples, i.e., glucosylation and double glucuronidation. The formation of metabolites that lead to a significant change in the chromophoric system of studied compounds, such as the reduction of carbonyl group in 7 H ‐benzo[c]fluorene‐7‐one chromophore, is reflected in their UV spectra, which provides valuable complementary information to MS/MS data. Copyright © 2011 John Wiley & Sons, Ltd.