title: Oxidation of indometacin by ferrate (VI): kinetics, degradation pathways, and toxicity assessment.
abstract: The oxidation of indometacin (IDM) by ferrate(VI) (Fe(VI)) was investigated to determine the reaction kinetics, transformation products, and changes in toxicity. The reaction between IDM and Fe(VI) followed first-order kinetics with respect to each reactant. The apparent second-order rate constants (kapp) decreased from 9.35 to 6.52 M-1s-1, as the pH of the solution increased from 7.0 to 10.0. The pH dependence of kappmight be well explained by considering the species-specific rate constants of the reactions of IDM with Fe(VI). Detailed product studies using liquid chromatography-tandem mass spectrometry (LC-MS/MS) indicated that the oxidation products were primarily derived from the hydrolysis of amide linkages, the addition of hydroxyl groups, and electrophilic oxidation. The toxicity of the oxidation products was evaluated using the Microtox test, which indicated that transformation products exhibited less toxicity to the Vibrio fischeri bacteria. Quantitative structure-activity relationship (QSAR) analysis calculated by the ecological structure activity relationship (ECOSAR) revealed that all of the identified products exhibited lower acute and chronic toxicity than the parent pharmaceutical for fish, daphnid, and green algae. Furthermore, Fe(VI) was effective in the degradation IDM in water containing carbonate ions or fulvic acid (FA), and in lake water samples; however, higher Fe(VI) dosages would be required to completely remove IDM in lake water in contrast to deionized water.
authors.affiliation: School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou Higher Education Mega Center, Panyu District, No. 100 Waihuan Xi Road, Guangzhou, 510006, People's Republic of China.
authors.forename: Junlei
authors.initials: J
authors.lastname: Huang
authors.affiliation: School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou Higher Education Mega Center, Panyu District, No. 100 Waihuan Xi Road, Guangzhou, 510006, People's Republic of China.
authors.forename: Yahui
authors.initials: Y
authors.lastname: Wang
authors.affiliation: School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou Higher Education Mega Center, Panyu District, No. 100 Waihuan Xi Road, Guangzhou, 510006, People's Republic of China. liugg615@163.com.
authors.forename: Guoguang
authors.initials: G
authors.lastname: Liu
authors.affiliation: School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou Higher Education Mega Center, Panyu District, No. 100 Waihuan Xi Road, Guangzhou, 510006, People's Republic of China.
authors.forename: Ping
authors.initials: P
authors.lastname: Chen
authors.affiliation: School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou Higher Education Mega Center, Panyu District, No. 100 Waihuan Xi Road, Guangzhou, 510006, People's Republic of China.
authors.forename: Fengliang
authors.initials: F
authors.lastname: Wang
authors.affiliation: School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou Higher Education Mega Center, Panyu District, No. 100 Waihuan Xi Road, Guangzhou, 510006, People's Republic of China.
authors.forename: Jingshuai
authors.initials: J
authors.lastname: Ma
authors.affiliation: School of Environmental and Chemical, Foshan University, Foshan, 528000, People's Republic of China.
authors.forename: Fuhua
authors.initials: F
authors.lastname: Li
authors.affiliation: School of Environment, Henan Normal University, Xinxiang, 453007, People's Republic of China.
authors.forename: Haijin
authors.initials: H
authors.lastname: Liu
authors.affiliation: School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou Higher Education Mega Center, Panyu District, No. 100 Waihuan Xi Road, Guangzhou, 510006, People's Republic of China.
authors.forename: Wenying
authors.initials: W
authors.lastname: Lv
mesh_terms: D006863:Hydrogen-Ion Concentration; D007213:Indomethacin; D007501:Iron / Q000737:chemistry; D007700:Kinetics; D010084:Oxidation-Reduction; D053719:Tandem Mass Spectrometry
chemical_list: C017311:ferrate ion; D007501:Iron; D007213:Indomethacin
keywords: Ferrate (VI); Indometacin; Kinetics; Oxidation products; Toxicity