title: Photocatalytic transformation of acesulfame: Transformation products identification and embryotoxicity study.
abstract: Artificial sweeteners have been recognized as emerging contaminants due to their wide application, environmental persistence and ubiquitous occurrence. Among them, acesulfame has attracted much attention. After being discharged into the environment, acesulfame undergoes photolysis naturally. However, acesulfame photodegradation behavior and identity of its transformation products, critical to understanding acesulfame's environmental impact, have not been thoroughly investigated. The present study aimed to fill this knowledge gap by a laboratory simulation study in examining acesulfame transformation products and pathways under UV-C photolysis in the presence of TiO2. Photodegradation products of acesulfame were isolated and analyzed using the LC-IM-QTOF-MS coupled with LC Ion Trap MS in the MS(n) mode. Our results show six new transformation products that have not been previously identified. The molecular structures and transformation pathways were proposed. Further embryotoxicity tests showed that acesulfame transformation products at the low g L(-1) level produced significant adverse effects in tail detachment, heart rate, hatching rate and survival rate during fish embryo development. The identification of additional transformation products with proposed transformation pathways of acesulfame, the increased toxicity of acesulfame after photolysis, and the fact that the accumulation of acesulfame transformation products is increasingly likely make acesulfame contamination even more important. Water resource control agencies need to consider legislation regarding acesulfame and other artificial sweeteners, while further studies are carried out, in order to protect the safety of this most vital resource.
authors.affiliation: Department of Chemistry, Hong Kong Baptist University, Kowloon Tong, Hong Kong Special Administrative Region; Key Laboratory of Tropical Agro-environment, Ministry of Agriculture of China, South China Agricultural University, Guangzhou 510642, China.
authors.forename: Adela Jing
authors.initials: AJ
authors.lastname: Li
authors.affiliation: Applied Analytical Chemistry, Faculty of Chemistry, University of Duisburg-Essen, Essen, Germany.
authors.forename: Oliver J
authors.initials: OJ
authors.lastname: Schmitz
authors.affiliation: Applied Analytical Chemistry, Faculty of Chemistry, University of Duisburg-Essen, Essen, Germany.
authors.forename: Susanne
authors.initials: S
authors.lastname: Stephan
authors.affiliation: Applied Analytical Chemistry, Faculty of Chemistry, University of Duisburg-Essen, Essen, Germany.
authors.forename: Claudia
authors.initials: C
authors.lastname: Lenzen
authors.affiliation: Department of Biology, Hong Kong Baptist University, Kowloon Tong, Hong Kong Special Administrative Region.
authors.forename: Patrick Ying-Kit
authors.initials: PY
authors.lastname: Yue
authors.affiliation: Key Laboratory of Tropical and Subtropical Fish Breeding & Cultivation, Pearl River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510380, China.
authors.forename: Kaibin
authors.initials: K
authors.lastname: Li
authors.affiliation: Key Laboratory of Tropical Agro-environment, Ministry of Agriculture of China, South China Agricultural University, Guangzhou 510642, China.
authors.forename: Huashou
authors.initials: H
authors.lastname: Li
authors.affiliation: Department of Chemistry, Hong Kong Baptist University, Kowloon Tong, Hong Kong Special Administrative Region; Partner State Key Laboratory of Environmental and Biological Analysis, Hong Kong Baptist University, Kowloon Tong, Hong Kong Special Administrative Region. Electronic address: s9362284@hkbu.edu.hk.
authors.forename: Kelvin Sze-Yin
authors.initials: KS
authors.lastname: Leung
mesh_terms: D000818:Animals; D002853:Chromatography, Liquid; D004625:Embryo, Nonmammalian; D013058:Mass Spectrometry; D010782:Photolysis; D013549:Sweetening Agents / Q000737:chemistry / Q000633:toxicity; D013843:Thiazines / Q000737:chemistry* / Q000633:toxicity*; D014025:Titanium / Q000737:chemistry; D023382:Toxicity Tests, Acute; D014466:Ultraviolet Rays; D014874:Water Pollutants, Chemical / Q000737:chemistry / Q000633:toxicity; D015027:Zebrafish / Q000196:embryology*
chemical_list: D013549:Sweetening Agents; D013843:Thiazines; D014874:Water Pollutants, Chemical; C009495:titanium dioxide; D014025:Titanium; C006362:acetosulfame
keywords: Acesulfame; Catalytic UV irradiation; Embryotoxicity; Emerging contaminant; Transformation pathway; Transformation product