title: Degradation of chiral neonicotinoid insecticide cycloxaprid in flooded and anoxic soil.
abstract: Cycloxaprid (CYC), with two stereogenic centers from oxabridged ring, is a novel potent neonicotinoid insecticide. The investigation of relevant transformation products (TPs) is critical for the risk evaluation of CYC on environment impact and further regulatory decisions. In this study, stereoselective soil metabolism of CYC enantiomers was investigated using isotope labeling techniques. Liquid scintillation counting with LC-MS/MS was used to identify and quantify the major transformation products (TPs) of CYC enantiomers in four various soils under anoxic and flooded condition. Most of CYC had been transformed in four soils at 5d after treatment. Furthermore, CYC was found converted to a range of transformation products, which exhibited soil-specific dynamic changes. Cleavage of the oxabridged seven-member ring, reductive dechlorination in the chloropyridinyl and cleavage of C-N between the chloropyridinylmethyl and imidazalidine ring are the main transformation pathways of CYC. It is presumed that acidic condition may conduce to form the cleavage product of oxabridged seven-member ring. However, abiotic or biotic stereoselective persistence of TPs in all soils was not observed from the experimental data and may be attributed to the unstable oxabridged ring.
authors.affiliation: Shanghai Key Laboratory of Chemical Biology, School of Pharmacy, East China University of Science and Technology, Shanghai 200237, China.
authors.forename: Xuanqi
authors.initials: X
authors.lastname: Liu
authors.affiliation: Shanghai Key Laboratory of Chemical Biology, School of Pharmacy, East China University of Science and Technology, Shanghai 200237, China.
authors.forename: Xiaoyong
authors.initials: X
authors.lastname: Xu
authors.affiliation: Shanghai Key Laboratory of Chemical Biology, School of Pharmacy, East China University of Science and Technology, Shanghai 200237, China.
authors.forename: Chao
authors.initials: C
authors.lastname: Li
authors.affiliation: Institute of Nuclear Agricultural Sciences, Zhejiang University, Hangzhou 310029, China.
authors.forename: Hanxue
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Institute of Nuclear Agricultural Sciences, Zhejiang University, Hangzhou 310029, China.
authors.forename: Qiuguo
authors.initials: Q
authors.lastname: Fu
authors.affiliation: Shanghai Key Laboratory of Chemical Biology, School of Pharmacy, East China University of Science and Technology, Shanghai 200237, China.
authors.forename: Xusheng
authors.initials: X
authors.lastname: Shao
authors.affiliation: Institute of Nuclear Agricultural Sciences, Zhejiang University, Hangzhou 310029, China. Electronic address: qfye@zju.edu.cn.
authors.forename: Qingfu
authors.initials: Q
authors.lastname: Ye
authors.affiliation: Shanghai Key Laboratory of Chemical Biology, School of Pharmacy, East China University of Science and Technology, Shanghai 200237, China. Electronic address: lizhong@ecust.edu.cn.
authors.forename: Zhong
authors.initials: Z
authors.lastname: Li
mesh_terms: D002851:Chromatography, High Pressure Liquid; D055868:Floods; D006575:Heterocyclic Compounds, 3-Ring / Q000737:chemistry / Q000378:metabolism; D007306:Insecticides / Q000737:chemistry / Q000378:metabolism; D010100:Oxygen; D011725:Pyridines / Q000737:chemistry / Q000378:metabolism; D012987:Soil / Q000737:chemistry; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000737:chemistry / Q000378:metabolism; D013237:Stereoisomerism; D053719:Tandem Mass Spectrometry
chemical_list: D006575:Heterocyclic Compounds, 3-Ring; D007306:Insecticides; D011725:Pyridines; D012987:Soil; D012989:Soil Pollutants; C583366:cycloxaprid; D010100:Oxygen
keywords: Chiral; Cycloxaprid; Dynamic; Isotope labeling; Pathway; Soil degradation