title: The chiral separation and enantioselective degradation of the chiral herbicide napropamide.
abstract: The chiral pesticide enantiomers often have different toxic effects and environmental behaviors, which suggests that the risk assessments should be on an enantiomeric level. In this work, the chiral separation of the napropamide enantiomers and the stereoselective degradation in tomato, cucumber, rape, cabbage, and soil were investigated. Napropamide enantiomers could be separated absolutely by high-performance liquid chromatography (HPLC) using a Chiralpak IC column with a resolution factor of 11.75 under the optimized condition. Solid phase extraction (SPE) was used for cleanup of the enantiomers in the vegetable samples. The residue analysis method was validated. Good linearities (R(2)  = 0.9997) and recoveries (71.43% -97.64%) were obtained. The limits of detection (LOD) were 0.05 mg/kg in soil and 0.20 mg/kg in vegetables. The results of degradation showed that napropamide dissipated rapidly in vegetables with half-lives of only 1.13-2.21 days, but much more slowly in soil, with a half-life of 11.95 d. Slight stereoselective degradation of the two enantiomers was only observed in cabbage, with enantiomeric fraction (EF) = 0.46, and there was no enantioselectivity in the other vegetables. The degradation of napropamide in the five matrixes was fast, and there was no enantioselectivity.
authors.affiliation: Department of Applied Chemistry, China Agricultural University, Beijing, PR China.
authors.forename: Yanli
authors.initials: Y
authors.lastname: Qi
authors.forename: Donghui
authors.initials: D
authors.lastname: Liu
authors.forename: Mingjing
authors.initials: M
authors.lastname: Sun
authors.forename: Shanshan
authors.initials: S
authors.lastname: Di
authors.forename: Peng
authors.initials: P
authors.lastname: Wang
authors.forename: Zhiqiang
authors.initials: Z
authors.lastname: Zhou
mesh_terms: D002851:Chromatography, High Pressure Liquid; D006540:Herbicides / Q000737:chemistry / Q000378:metabolism; D007700:Kinetics; D015394:Molecular Structure; D009281:Naphthalenes / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism*; D012989:Soil Pollutants / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D013237:Stereoisomerism; D014675:Vegetables / Q000737:chemistry
chemical_list: D006540:Herbicides; D009281:Naphthalenes; D012989:Soil Pollutants; C010909:devrinol
keywords: chiral separation; enantioselective degradation; napropamide