title: Comparative study of the selective degradations of two enantiomers in the racemate and an enriched concentration of indoxacarb in soils.
abstract: In this study, selective degradations of the two enantiomers of indoxacarb in the concentrate (2.33S/1R) and racemate (1S/1R) are examined. The absolute configurations of indoxacarb enantiomers were determined using X-ray diffraction. The results showed that in two alkaline soils, the S-(+)-indoxacarb was preferentially degraded in both the concentrate and racemate. In one acid soil, the two enantiomers degraded no-selectivity. In another acid soil and one neutral soil, the R-(-)-indoxacarb was preferentially degraded in both the concentrate and racemate. Indoxacarb enantiomers were configurationally stable in the five soils, and no interconversion was observed during the incubation. Because no significant difference in degradation was observed after samples were sterilized, the observed enantioselectivity may be attributed primarily to microbial activity in soils. The results indicate that the selective degradation behavior was the same for both formulations that were tested.
authors.affiliation: State Key Laboratory Breeding Base of Green Pesticide and Agricultural Bioengineering, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Guizhou University , Huaxi District, Guiyang 550025, PR China.
authors.forename: Yu-Ping
authors.initials: YP
authors.lastname: Zhang
authors.forename: De-Yu
authors.initials: DY
authors.lastname: Hu
authors.forename: Hu-Rong
authors.initials: HR
authors.lastname: Ling
authors.forename: Lei
authors.initials: L
authors.lastname: Zhong
authors.forename: An-Xiang
authors.initials: AX
authors.lastname: Huang
authors.forename: Kan-Kan
authors.initials: KK
authors.lastname: Zhang
authors.forename: Bao-An
authors.initials: BA
authors.lastname: Song
mesh_terms: D003460:Crystallization; D006863:Hydrogen-Ion Concentration; D007306:Insecticides; D015394:Molecular Structure; D010078:Oxazines / Q000032:analysis* / Q000737:chemistry* / Q000378:metabolism; D012987:Soil / Q000737:chemistry*; D012988:Soil Microbiology; D013237:Stereoisomerism; D014961:X-Ray Diffraction
chemical_list: D007306:Insecticides; D010078:Oxazines; D012987:Soil; C401104:indoxacarb
keywords: absolute configuration; enantiomers; enantioselective degradation; indoxacarb; soil