title: Assessment of quinoxyfen phototransformation pathways by liquid chromatography coupled to accurate mass spectrometry.
abstract: Quinoxyfen has been recently identified as a priority hazardous substance in the field of the European water policy. In this work, its fate in aqueous samples and solid supports under UV and solar radiation is investigated. Diverse degradation experiments were carried out, at lab scale, using spiked aliquots of different aqueous matrices (ultrapure, treated wastewater and river water) irradiated at different wavelengths (λ = 254 nm, λ = 365 nm and solar light). Half-lives of quinoxyfen (2-26 min) depended on the wavelength and the intensity of radiation whilst the nature of the aqueous matrix did not play an important role in degradation kinetics. Moreover, experiments under solar radiation of doped silicone tubes were performed to simulate degradation when quinoxyfen is adsorbed on plant leaves or soil. As the compound is not completely mineralized, the identification of quinoxyfen transformation products (TPs) was performed by liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QTOF-MS) injection of different irradiated time aliquots. The full-fragment ion spectra, at different collision energies, allowed the elucidation of the chemical structure of TPs formed by hydroxylation, cyclization or cleavage reactions. Five out of seven identified TPs have not been reported previously. The ecotoxicity simulation by software (TEST and ECOSAR) for TPs revealed that some of them could cause harmful effects to organisms such as Daphnia magna or Fathead minnow in a similar extent to the precursor; moreover, the time course profiles of major TPs (TP1 and TP2) revealed a much higher resistance to further photodegradation than quinoxyfen. Graphical abstract Quinoxyfen phototransformation pathways.
authors.affiliation: Departamento de Química Analítica, Nutrición y Bromatología, Instituto de Investigación y Análisis Alimentario (IIAA), Universidad de Santiago de Compostela, Santiago de Compostela, 15782, Spain.|Postgraduate Program in Chemical Engineering, Universidade Estadual de Maringá, Maringá, Paraná, 87020-900, Brazil.
authors.forename: Priscila
authors.initials: P
authors.lastname: Ferri
authors.affiliation: Departamento de Química Analítica, Nutrición y Bromatología, Instituto de Investigación y Análisis Alimentario (IIAA), Universidad de Santiago de Compostela, Santiago de Compostela, 15782, Spain. maria.ramil@usc.es.
authors.forename: María
authors.initials: M
authors.lastname: Ramil
authors.affiliation: Departamento de Química Analítica, Nutrición y Bromatología, Instituto de Investigación y Análisis Alimentario (IIAA), Universidad de Santiago de Compostela, Santiago de Compostela, 15782, Spain.
authors.forename: Isaac
authors.initials: I
authors.lastname: Rodríguez
authors.affiliation: Postgraduate Program in Chemical Engineering, Universidade Estadual de Maringá, Maringá, Paraná, 87020-900, Brazil.
authors.forename: Rosângela
authors.initials: R
authors.lastname: Bergamasco
authors.affiliation: Postgraduate Program in Chemical Engineering, Universidade Estadual de Maringá, Maringá, Paraná, 87020-900, Brazil.|Postgraduate Program in Food Science, Universidade Estadual de Maringá, Maringá, Paraná, 87020-900, Brazil.
authors.forename: Angélica Marquetotti Salcedo
authors.initials: AM
authors.lastname: Vieira
authors.affiliation: Departamento de Química Analítica, Nutrición y Bromatología, Instituto de Investigación y Análisis Alimentario (IIAA), Universidad de Santiago de Compostela, Santiago de Compostela, 15782, Spain.
authors.forename: Rafael
authors.initials: R
authors.lastname: Cela
mesh_terms: D002853:Chromatography, Liquid / Q000379:methods*; D004307:Dose-Response Relationship, Radiation; D013058:Mass Spectrometry / Q000379:methods*; D011804:Quinolines / Q000032:analysis / Q000737:chemistry* / Q000528:radiation effects*; D011829:Radiation Dosage; D012993:Solar Energy; D014466:Ultraviolet Rays; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000737:chemistry* / Q000528:radiation effects*
chemical_list: D011804:Quinolines; D014874:Water Pollutants, Chemical; C470613:quinoxyfen
keywords: Liquid chromatography; Photodegradation; Quinoxyfen; Time-of-flight mass spectrometry; Transformation products