title: Sunlight photolysis of benzotriazoles - Identification of transformation products and pathways.
abstract: Benzotriazoles (BTs) are widely used corrosion inhibitors, incompletely removed in municipal wastewater treatment. The photochemical fate of the three BTs 1H-benzotriazole (1H-BT), 4-methyl-1H-benzotriazole (4Me-BT) and 5-methyl-1H-benzotriazole (5Me-BT) and of three microbial metabolites, was studied under simulated sunlight (290-800 nm) at neutral pH in aqueous solution for 24 h. The half-life, the quantum yield and the reaction rate were determined and a total of 36 photolysis products were detected and identified using liquid chromatography-high resolution-mass spectrometry. The half-lives of all six BTs were in the range of 6-24 h under the experimental conditions. Though the quantum yields were comparatively low (0.0007-0.0021), the environmental half-lives ranged from 2.4 to 8 d, suggesting that sunlight photolysis is still a relevant degradation process of BTs in surface waters. The photolysis pathway of 1H-BT under simulated sunlight differed from that suggested for UV-radiation, in that aminophenol is formed directly rather than via aniline. Similar pathways were found for the other BTs, except for 4-hydroxy-1H-benzotriazole (4OH-BT). Most identified transformation products of the BTs showed a high reactivity and appear not to persist in the environment. Upon co-photolysis of BTs with dissolved organic matter (DOM), however, series of reaction products were determined by Fourier transform - ion cyclotron resonance - mass spectrometry (FTICR-MS) which are formed by reaction of photolysis intermediates of the BTs with DOM.
authors.affiliation: Department of Analytical Chemistry, Helmholtz Centre for Environmental Research - UFZ, Permoserstrasse 15, D-04318, Leipzig, Germany.
authors.forename: Cindy
authors.initials: C
authors.lastname: Weidauer
authors.affiliation: Department of Analytical Chemistry, Helmholtz Centre for Environmental Research - UFZ, Permoserstrasse 15, D-04318, Leipzig, Germany.
authors.forename: Caroline
authors.initials: C
authors.lastname: Davis
authors.affiliation: Department of Analytical Chemistry, Helmholtz Centre for Environmental Research - UFZ, Permoserstrasse 15, D-04318, Leipzig, Germany.
authors.forename: Julia
authors.initials: J
authors.lastname: Raeke
authors.affiliation: Department of Analytical Chemistry, Helmholtz Centre for Environmental Research - UFZ, Permoserstrasse 15, D-04318, Leipzig, Germany.
authors.forename: Bettina
authors.initials: B
authors.lastname: Seiwert
authors.affiliation: Department of Analytical Chemistry, Helmholtz Centre for Environmental Research - UFZ, Permoserstrasse 15, D-04318, Leipzig, Germany. Electronic address: thorsten.reemtsma@ufz.de.
authors.forename: Thorsten
authors.initials: T
authors.lastname: Reemtsma
mesh_terms: D001673:Biodegradation, Environmental / Q000528:radiation effects*; D001711:Biotransformation / Q000528:radiation effects*; D002853:Chromatography, Liquid; D006207:Half-Life; D010782:Photolysis; D013472:Sunlight; D014230:Triazoles / Q000737:chemistry* / Q000528:radiation effects; D014867:Water / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000737:chemistry* / Q000528:radiation effects
chemical_list: D014230:Triazoles; D014874:Water Pollutants, Chemical; D014867:Water; C012771:benzotriazole
keywords: Corrosion inhibitors; Kinetics; Natural organic matter; Photochemical fate; Ultrahigh-resolution mass spectrometry