Residue decline study of ethiprole in paddy field soil and water

In order to study the safety of ethiprole to paddy soil ecosystem,residue decline of ethiprole in soil and water were investigated under field and field-simulated condition.The samples were extracted by acetic-acetonitrile(1∶99, V∶V),cleaned up with primary secondary amine (PSA),and analyzed by UPLC-MS/MS.External reference method was used for quantitative determination.The linearity was satisfied (r>0.98) in the concentration range of 0.001-0.1 mg/L.The limit of detection(LOD) was 2.2×10-13 g,and the limit of quantification (LOQ) in paddy soil and water were 0.001 mg/kg(L).The average fortification recoveries varied from 80.2% to 119.5% with relative standard deviation (RSD) of 3.1%-9.0% when ethiprole was spiked at 0.002-1.0 mg/kg level in soil matrix,the average fortification recoveries varied from 94.2%-108.2% with relative standard deviation (RSD) of 1.6%-13.2% when ethiprole was spiked at 0.001-1.0 mg/L level in water matrix.The decline study of ethiprole residue in paddy field soil and water were carried out,the decline curves accorded with the first-order kinetics equation,and the half-lives of ethiprole in soil and water under field-simulated and field condition were of 3.2-2.8 d and 3.5-1.8 d,respectively.Ethiprole belongs to the easily degradable pesticide.