Enantioselective environmental behavior of the chiral herbicide fenoxaprop-ethyl and its chiral metabolite fenoxaprop in soil.
The enantioselective degradation behavior of fenoxaprop-ethyl (FE) and its chiral metabolite fenoxaprop (FA) in three soils under native conditions was investigated. Two pairs of enantiomers were analyzed by high-performance liquid chromatography (HPLC) with an amylose tri-(3,5-dimethylphenylcarbamate) (ADMPC) chiral column. The degradation of racemic FE in three soils showed the herbicidally inactive S-(-)-enantiomer degraded faster than the active R-(+)-enantiomer. FE was configurationally stable in soils because no interconversion to the respective antipodes was observed during incubation of the enantiopure S-(-)- or R-(+)-FE. The main metabolites of FE were confirmed as FA and 6-chloro-2,3-dihydrobenzoxazol-2-one (CDHB), and the formation of the chiral metabolite FA showed enantioselectivity in soils. The degradation of rac-FA was also enantioselective with the S-(-)-FA preferentially degraded: the half-life (t(1/2)) of the S-form in the three soils ranged from 2.03 to 5.17 days, and that of R-form ranged from 2.42 to 20.39 days. The inversion of the S-(-)-enantiomer into the R-(+)-enantiomer occurred in two of the three soils when the enantiopure S-(-)- and R-(+)-FA were incubated. The data from sterilized control experiments indicated that the enantioselectivity of FE and FA was attributed to microbially mediated processes.
Department of Applied Chemistry, China Agricultural University, Beijing 100193, China.
Yanfeng
Y
Zhang
Donghui
D
Liu
Jinling
J
Diao
Zeying
Z
He
Zhiqiang
Z
Zhou
Peng
P
Wang
Xuefeng
X
Li
D005659:Fungicides, Industrial / Q000737:chemistry*; D006540:Herbicides / Q000737:chemistry*; D015394:Molecular Structure; D010080:Oxazoles / Q000737:chemistry*; D011422:Propionates / Q000737:chemistry*; D012987:Soil / Q000032:analysis; D012989:Soil Pollutants / Q000737:chemistry*; D013237:Stereoisomerism
D005659:Fungicides, Industrial; D006540:Herbicides; D010080:Oxazoles; D011422:Propionates; D012987:Soil; D012989:Soil Pollutants; C416661:fenoxaprop ethyl