Biodegradation pathway of mesotrione: Complementarities of NMR, LC–NMR and LC–MS for qualitative and quantitative metabolic profiling

• Published in: Chemosphere (Oxford) Vol. 81; no. 3; pp. 372 - 380
• Main Authors: Durand, Stéphanie, Sancelme, Martine, Besse-Hoggan, Pascale, Combourieu, Bruno
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01-09-2010; Elsevier
• Subjects: Applied sciences; Bacillus - metabolism; Bacteria; Biodegradation, Environmental; Chromatography, Liquid - methods; Cyclohexanones - chemistry; Cyclohexanones - metabolism; Environmental Pollutants - chemistry; Environmental Pollutants - metabolism; Environmental Sciences; Exact sciences and technology; Herbicides - chemistry; Herbicides - metabolism; LC–MS; LC–NMR; Life Sciences; Magnetic fields; Magnetic Resonance Spectroscopy - methods; Mass Spectrometry - methods; Mesotrione; Metabolic Networks and Pathways; Metabolic profiling; Metabolites; NMR spectroscopy; Nuclear magnetic resonance; Pathways; Pollution; Profiling; Spectroscopy; Transformations; Metabolic profiling; LC–NMR; Mesotrione; Metabolites; NMR spectroscopy; LC–MS; Agricultural chemical product; Metabolite; Identification; NMR spectrometry; Metabolic pathway; Chemical pollution; Health and environment; Ecosystem; Nuclear magnetic resonance; Magnetic field; Public health; Xenobiotic; Organic compounds; Biodegradation; Pollutant behavior; Pesticides; Liquid chromatography; LC-NMR; Herbicide; LC-MS; Degradation product; Mass spectrometry
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2010.07.017

Enhanced knowledge of pesticide transformation products formed in the environment could lead to both accurate estimates of the overall effects of these compounds on environmental ecosystems and human health and improved removal processes. These compounds can present chemical and environmental behaviours completely different from the starting active ingredient. The difficulty lies on their identification or/and their quantification due to the lack of analytical reference standards. In this context,
ex situ Nuclear Magnetic Resonance (NMR) and Liquid Chromatography–NMR (LC–NMR) were used as complementary tools to LC–Mass Spectrometry (MS) to define the metabolic pathway of mesotrione, an emergent herbicide, by the bacterial strain
Bacillus sp. 3B6. The complementarities of
ex situ and LC–NMR allowed us to unambiguously identify six metabolites whereas the structures of only four metabolites were suggested by LC–MS. The presence of a new metabolic pathway was evidenced by NMR. These results demonstrate that NMR and LC–NMR spectroscopy provided unambiguous structural information for xenobiotic metabolic profiling, even at moderate magnetic field and allowed direct absolute quantification despite the lack of commercial or synthetic standards, required for LC–MS techniques.