title: Enantiomerization and enantioselective bioaccumulation of metalaxyl in Tenebrio molitor larvae.
abstract: The enantiomerization and enantioselective bioaccumulation of metalaxyl by a single dose of exposure to Tenebrio molitor larvae under laboratory condition were studied by high-performance liquid chromatography tandem mass spectroscopy (HPLC-MS/MS) based on a ChiralcelOD-3R [cellulosetris-tris-(3, 5-dichlorophenyl-carbamate)] column. Exposure of enantiopure R-metalaxyl and S-metalaxyl in Tenebrio molitor larvae exhibited significant enantiomerization, with formation of the R enantiomers from the S enantiomers, and vice versa, which might be attributed to the chiral pesticide catalyzed by a certain enzyme in Tenebrio molitor larvae. Enantiomerization was not observed in wheat bran during the period of 21 d. In addition, bioaccumulation of rac-metalaxyl in Tenebrio molitor larvae was enantioselective with a preferential accumulation of S-metalaxyl. These results showed that enantioselectivity was caused not only by actual degradation and metabolism but also by enantiomerization, which was an important process in the environmental fate and behavior of metalaxyl enantiomers.
authors.affiliation: Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences Haidian District, Beijing, China.
authors.forename: Yongxin
authors.initials: Y
authors.lastname: Gao
authors.forename: Huili
authors.initials: H
authors.lastname: Wang
authors.forename: Fang
authors.initials: F
authors.lastname: Qin
authors.forename: Peng
authors.initials: P
authors.lastname: Xu
authors.forename: Xiaotian
authors.initials: X
authors.lastname: Lv
authors.forename: Jianzhong
authors.initials: J
authors.lastname: Li
authors.forename: Baoyuan
authors.initials: B
authors.lastname: Guo
mesh_terms: D000409:Alanine / Q000031:analogs & derivatives* / Q000032:analysis / Q000378:metabolism; D000818:Animals; D002851:Chromatography, High Pressure Liquid; D004043:Dietary Fiber; D005659:Fungicides, Industrial / Q000737:chemistry*; D007814:Larva; D015394:Molecular Structure; D013237:Stereoisomerism; D053719:Tandem Mass Spectrometry; D013712:Tenebrio / Q000737:chemistry / Q000378:metabolism*
chemical_list: D004043:Dietary Fiber; D005659:Fungicides, Industrial; C028175:metalaxyl; D000409:Alanine
keywords: Tenebrio molitor larvae; bioaccumulation; enantiomerization; enantioselectivity; metalaxyl