title: Identification of halogenated photoproducts generated after ultraviolet-irradiation of parabens and benzoates in water containing chlorine by solid-phase microextraction and gas chromatography-mass spectrometry.
abstract: This work presents a new solid-phase microextraction (SPME)-based approach to investigate the formation of halogenated by-products generated by the UV-induced photodegradation of parabens and their congener benzoates in water containing chlorine. Degradation of parent species, and further identification of their transformation by-products were monitored by gas chromatography coupled to mass spectrometry (GC/MS). In order to improve detectability, SPME was applied as a preconcentration step after UV-irradiation of target preservatives. Experiments performed with dechlorinated water, ultrapure water, and tap water showed that under UV-light, the presence of even low levels of free chlorine, increases the photodegradation rate of target preservatives, enhancing the formation of halogenated photoproducts. Monobrominated, dibrominated and bromochlorinated hydroxybenzoates were identified, and the transformation of benzoates into halogenated parabens was also confirmed. Bromination is expected to occur when free chlorine is present, due to the presence of traces of bromide in water samples. Five halogenated phenols (mainly brominated) were detected as breakdown photoproducts from both families of target preservatives. On the basis of the appearance of the aforementioned by-products, a tentative transformation pathway, consistent with the photoformation-photodecay kinetics of the by-products, is proposed herein for the first time.
authors.affiliation: Department of Analytical Chemistry, Nutrition and Food Science, Faculty of Chemistry, Campus Vida, University of Santiago de Compostela, E-15782 Santiago de Compostela, Spain.
authors.forename: Gerardo
authors.initials: G
authors.lastname: Alvarez-Rivera
authors.affiliation: Department of Analytical Chemistry, Nutrition and Food Science, Faculty of Chemistry, Campus Vida, University of Santiago de Compostela, E-15782 Santiago de Compostela, Spain.
authors.forename: Maria
authors.initials: M
authors.lastname: Llompart
authors.affiliation: Department of Analytical Chemistry, Nutrition and Food Science, Faculty of Chemistry, Campus Vida, University of Santiago de Compostela, E-15782 Santiago de Compostela, Spain.
authors.forename: Carmen
authors.initials: C
authors.lastname: Garcia-Jares
authors.affiliation: Department of Analytical Chemistry, Nutrition and Food Science, Faculty of Chemistry, Campus Vida, University of Santiago de Compostela, E-15782 Santiago de Compostela, Spain. Electronic address: marta.lores@usc.es.
authors.forename: Marta
authors.initials: M
authors.lastname: Lores
mesh_terms: D001565:Benzoates / Q000032:analysis* / Q000528:radiation effects; D002713:Chlorine / Q000737:chemistry; D004784:Environmental Monitoring / Q000295:instrumentation; D008401:Gas Chromatography-Mass Spectrometry; D054879:Halogenation; D010226:Parabens / Q000032:analysis* / Q000528:radiation effects; D010782:Photolysis; D052617:Solid Phase Microextraction; D014466:Ultraviolet Rays; D014867:Water / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000737:chemistry
chemical_list: D001565:Benzoates; D010226:Parabens; D014874:Water Pollutants, Chemical; D014867:Water; D002713:Chlorine
keywords: Bromophenols; GC–MS; Halogenated by-products; Personal care products; Photodegradation; Solid-phase microextraction