title: Identification of unwanted photoproducts of cosmetic preservatives in personal care products under ultraviolet-light using solid-phase microextraction and micro-matrix solid-phase dispersion.
abstract: The photochemical transformation of widely used cosmetic preservatives including benzoates, parabens, BHA, BHT and triclosan has been investigated in this work applying an innovative double-approach strategy: identification of transformation products in aqueous photodegradation experiments (UV-light, 254nm), followed by targeted screening analysis of such photoproducts in UV-irradiated cosmetic samples. Solid-phase microextraction (SPME) was applied, using different fiber coatings, in order to widen the range of detectable photoproducts in water, whereas UV-irradiated personal care products (PCPs) containing the target preservatives were extracted by micro-matrix solid-phase dispersion (micro-MSPD). Both SPME and micro-MSPD-based methodologies were successfully optimized and validated. Degradation kinetics of parent species, and photoformation of their transformation by-products were monitored by gas chromatography coupled to mass spectrometry (GC-MS). Thirty nine photoproducts were detected in aqueous photodegradation experiments, being tentatively identified based on their mass spectra. Transformation pathways between structurally related by-products, consistent with their kinetic behavior were postulated. The photoformation of unexpected photoproducts such as 2- and 4-hydroxybenzophenones, and 2,8-dichlorodibenzo-p-dioxin in PCPs are reported in this work 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. Electronic address: gerardo.alvarez@usc.es.
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.
authors.forename: Marta
authors.initials: M
authors.lastname: Lores
mesh_terms: D001565:Benzoates / Q000032:analysis; D003358:Cosmetics / Q000737:chemistry* / Q000528:radiation effects; D004147:Dioxins / Q000032:analysis; D008401:Gas Chromatography-Mass Spectrometry; D007700:Kinetics; D013058:Mass Spectrometry; D010226:Parabens / Q000032:analysis; D010782:Photolysis; D052617:Solid Phase Microextraction; D014260:Triclosan / Q000032:analysis; D014466:Ultraviolet Rays; D014867:Water / Q000737:chemistry
chemical_list: D001565:Benzoates; D003358:Cosmetics; D004147:Dioxins; D010226:Parabens; D014867:Water; D014260:Triclosan; C068993:2,8-dichlorodibenzo-4-dioxin
keywords: 2,8-Dichlorodibenzo-p-dioxin; Cosmetics; GC–MS; Micro-matrix solid-phase dispersion; Personal care products; Photodegradation; Preservatives; Solid-phase microextraction