title: Dissipation, residues and risk assessment of metaldehyde and niclosamide ethanolamine in pakchoi after field application.
abstract: A method using LC-MS/MS after QuEChERS preparation for the simultaneous determination of metaldehyde and niclosamide ethanolamine residues in soil and pakchoi has been developed and validated. The mean recoveries were ranged from 90% to 101% with RSDs (relative standard deviations) less than 9.2%. The dissipation results showed that the half-lives of metaldehyde and niclosamide ethanolamine were 2.3-4.3d and 1.7-9.5d, respectively. The terminal residue results indicated that the residues of metaldehyde in pakchoi were lower than the temporary maximum residue limits (MRL) set by China on 1 d after last treatment and the maximum residue of niclosamide ethanolamine in pakchoi was 0.54mg/kg. The risk quotients of metaldehyde and niclosamide ethanolamine were ranged from 0.015 to 0.033 and from 0.00064 to 0.0014, respectively. This work could provide guidance on reasonable use of these molluscicides and aid in the establishment of MRL in China.
authors.affiliation: Laboratory of Pesticide Residues and Environmental Toxicology, School of Chemistry and Biological Engineering, University of Science and Technology Beijing, Beijing 100083, PR China. Electronic address: idongbizhang@126.com.
authors.forename: Bizhang
authors.initials: B
authors.lastname: Dong
authors.affiliation: Laboratory of Pesticide Residues and Environmental Toxicology, School of Chemistry and Biological Engineering, University of Science and Technology Beijing, Beijing 100083, PR China. Electronic address: 1304490005@qq.com.
authors.forename: Xingjiao
authors.initials: X
authors.lastname: Shao
authors.affiliation: Laboratory of Pesticide Residues and Environmental Toxicology, School of Chemistry and Biological Engineering, University of Science and Technology Beijing, Beijing 100083, PR China. Electronic address: 982920596@qq.com.
authors.forename: Hongfang
authors.initials: H
authors.lastname: Lin
authors.affiliation: Laboratory of Pesticide Residues and Environmental Toxicology, School of Chemistry and Biological Engineering, University of Science and Technology Beijing, Beijing 100083, PR China. Electronic address: jyhu@ustb.edu.cn.
authors.forename: Jiye
authors.initials: J
authors.lastname: Hu
mesh_terms: D000079:Acetaldehyde / Q000031:analogs & derivatives* / Q000737:chemistry; D001937:Brassica / Q000737:chemistry*; D019856:Ethanolamine / Q000737:chemistry*; D009534:Niclosamide / Q000737:chemistry*; D018570:Risk Assessment; D012989:Soil Pollutants / Q000032:analysis
chemical_list: D012989:Soil Pollutants; C002935:metaldehyde; D019856:Ethanolamine; D009534:Niclosamide; D000079:Acetaldehyde
keywords: Dissipation; Metaldehyde; Niclosamide ethanolamine; Pakchoi; Residue; Risk assessment