Influence of soil properties on the enantioselective dissipation of the herbicide lactofen in soils.
A scheme was developed to elucidate the dissipation behaviors of the two enantiomers of the herbicide lactofen in soils using a normal-phase high-performance liquid chromatograph (HPLC) with UV detector and a column with a cellulose-tri-(3,5-dimethylphenylcarbamate)-based chiral stationary phase (CDMPC-CSP). Eight soils with a wide range of soil properties were studied. Racemic and the enantiopure (S)-(+)- and (R)-(-)-lactofen were incubated under aerobic and anaerobic conditions. The data from sterilized controls indicated that the dissipation of lactofen was biological. The dissipation was shown to be enantioselective with (S)-(+)-enantiomer being degraded faster than the (R)-(-)-enantiomer, resulting in residues enriched with (R)-(-)-lactofen when the racemic compound was incubated. Lactofen was configurationally stable in soil, showing no interconversion of (S)-(+)- to (R)-(-)- enantiomer and vice versa. Significant correlations of the enantioselectivity, expressed as ES = (k((S)) - k((R)))/(k((S)) + k((R))) of lactofen with soil pH were observed under aerobic and anaerobic conditions. In addition, we found that the enantioselectivity correlated with the soil texture rather than the organic carbon.
Diao
Jinling
J
Department of Applied Chemistry, China Agricultural University, Beijing 100193, China.
Lv
Chunguang
C
Wang
Xinquan
X
Dang
Ziheng
Z
Zhu
Wentao
W
Zhou
Zhiqiang
Z
D000332:Aerobiosis; D000693:Anaerobiosis; D004355:Drug Stability; D055768:Halogenated Diphenyl Ethers / Q000737:chemistry* / Q000378:metabolism; D006540:Herbicides / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D012987:Soil / Q000032:analysis*; D012988:Soil Microbiology; D013237:Stereoisomerism
D055768:Halogenated Diphenyl Ethers; D006540:Herbicides; D012987:Soil; C055370:lactofen