title: Identification and characterization of photodegradation products of metoprolol in the presence of natural fulvic acid by HPLC-UV-MSn.
abstract: Metoprolol is a β-blocker highly prescribed for the treatment of heart diseases. It is not efficiently removed in wastewater treatment plants and it has been detected not only in the treated effluents, but also in natural waters. Thus, the knowledge of its fate in the environment is an important issue, and photodegradation is an important degradation pathway. While direct photodegradation of metoprolol by solar light is not relevant, there is evidence in the literature that it suffers indirect photodegradation and a few studies have been published showing the important role of dissolved humic matter as photo-sensitizer. However, the identification of the photoproducts formed in the presence of humic matter is very poor, since only 2 photoproducts had been identified. This study investigated the degradation of metoprolol under simulated solar radiation and in the presence of fulvic acids (FA) extracted from a river. During the photodegradation experiments we observed the formation of new compounds which were separated and tentatively identified by HPLC-UV-ESI-MSn. At least 16 compounds were tentatively identified, including the 2 compounds previously identified in the literature and 4 new compounds which had not been detected by other authors as degradation products of metoprolol, even when submitted to artificial degradation processes.
authors.affiliation: CERNAS-Research Centre for Natural Resources, Environment and Society, College of Agriculture, Polytechnic Institute of Coimbra, Bencanta, 3045-601 Coimbra, Portugal. Electronic address: olga@esac.pt.
authors.forename: Olga M S
authors.initials: OMS
authors.lastname: Filipe
authors.affiliation: CERNAS-Research Centre for Natural Resources, Environment and Society, College of Agriculture, Polytechnic Institute of Coimbra, Bencanta, 3045-601 Coimbra, Portugal; CICECO, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal; QOPNA, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal; CESAM, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal.
authors.forename: Nuno
authors.initials: N
authors.lastname: Mota
authors.affiliation: CICECO, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal.
authors.forename: Sónia A O
authors.initials: SAO
authors.lastname: Santos
authors.affiliation: QOPNA, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal.
authors.forename: M Rosário M
authors.initials: MRM
authors.lastname: Domingues
authors.affiliation: CICECO, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal.
authors.forename: Armando J D
authors.initials: AJD
authors.lastname: Silvestre
authors.affiliation: QOPNA, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal.
authors.forename: M Graça P M S
authors.initials: MGPMS
authors.lastname: Neves
authors.affiliation: QOPNA, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal.
authors.forename: Mário M Q
authors.initials: MMQ
authors.lastname: Simões
authors.affiliation: CESAM, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal.
authors.forename: Eduarda B H
authors.initials: EBH
authors.lastname: Santos
mesh_terms: D001578:Benzopyrans / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D004350:Drug Residues / Q000737:chemistry / Q000528:radiation effects; D006812:Humic Substances; D007536:Isomerism; D013058:Mass Spectrometry; D008790:Metoprolol / Q000737:chemistry* / Q000528:radiation effects*; D010782:Photolysis; D013056:Spectrophotometry, Ultraviolet; D013472:Sunlight; D014865:Waste Disposal, Fluid; D062065:Wastewater / Q000032:analysis
chemical_list: D001578:Benzopyrans; D006812:Humic Substances; D008790:Metoprolol; D062065:Wastewater; C005023:fulvic acid
keywords: Degradation products; HPLC–MS(n); Metoprolol; Natural fulvic acids; Photodegradation; β-Blockers