Dietary Assessment of Esfenvalerate with Chiral Aspects in Crop Residues

摘要

@@ Esfenvalerate, a [ 2S, alpha-S] isomer of fenvalerate [(RS)-alpha-cyano-3-phenoxybenzyl CRS)-2-(4-chlorophenyl)-3-methylbutyrate]，is a broad-spectrum pyrethroid insecticide for many crops and widely used in the world. Technical grade of esfenvalerate, enriched with the [2S, alpha-S] isomer, also contains three other stereoisomers. In the past field trials, residues of esfenvalerate have been obtained as sum of four isomers, which is equivalent to fenvalerate. Although enantiomerization at either chiral centers has been demonstrated rarely to proceed through plant metabolism studies using radiolabels, no information are available on the behavior of esfenvalerate and its isomers in the field.