title: Different enantioselective degradation of pyraclofos in soils.
abstract: This study investigated the enantioselective degradation behavior of pyraclofos in three soils (NC, HZ, and ZZ) under native and sterilized conditions. The absolute configuration of pyraclofos enantiomers has been determined by the combination of experimental and calculated electronic circular dichroism spectra. S-(+)- and R-(-)-Pyraclofos were separated and determined on a cellulose tri-(4-chloro-3-methylphenylcarbamate) (Lux Cellulose-4) chiral column by reversed-phase high-performance liquid chromatography-tandem mass spectrometry. Pyraclofos enantiomers were configurationally stable in three soils and no interconversion was observed during the incubation of enantiopure S-(+)- or R-(-)-pyraclofos under native conditions. The enantioselective degradation behavior of chiral pyraclofos was dramatically different in three soils under native conditions, with half-lives (t(1/2)) of pyraclofos in NC, HZ, and ZZ soils of 2.6, 13.4, and 7.8 days for S-(+)-pyraclofos and 9.2, 9.3, and 8.2 days for R-(-)-pyraclofos. Compared to the half-lives (t(1/2)) of rac-pyraclofos of 21.5, 55.9, and 14.4 days in sterilized NC, HZ and ZZ soils, the degradation velocity was greatly improved in native soils, indicating that degradation was greatly attributed to microbially mediated processes in agricultural cultivating soils.
authors.affiliation: Environmental Resources and Soil Fertilizer Institute, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China.
authors.forename: Yuxin
authors.initials: Y
authors.lastname: Xu
authors.forename: Hu
authors.initials: H
authors.lastname: Zhang
authors.forename: Shulin
authors.initials: S
authors.lastname: Zhuang
authors.forename: Man
authors.initials: M
authors.lastname: Yu
authors.forename: Hua
authors.initials: H
authors.lastname: Xiao
authors.forename: Mingrong
authors.initials: M
authors.lastname: Qian
mesh_terms: D004355:Drug Stability; D006207:Half-Life; D063086:Organothiophosphates / Q000737:chemistry* / Q000378:metabolism; D010575:Pesticides / Q000737:chemistry*; D012987:Soil / Q000737:chemistry*; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000737:chemistry; D013237:Stereoisomerism; D013329:Structure-Activity Relationship
chemical_list: D063086:Organothiophosphates; D010575:Pesticides; D012987:Soil; D012989:Soil Pollutants; C069547:pyraclofos