Residue Dynamics of Famoxadone in Apple and Soil

Residual dynamics and final residue of famoxadone in apple and soil were studied by HPLC.Residues of famoxadone were extracted from apple and soil with menthol,concentrated and determined by HPLC with UV detector.The lowest detection limit of instrument for famoxadone was 2.0×10~(-10)g,and the limits of quantification in apple and soil were 0.004 and(0.002) mg·kg~(-1) respectively.The average recovery was 89.7%~100.6%,and coefficient of variation was 0.13%~10.10%,respectively.The half-lives of famoxadone in apple and soil were 11.6 days and 6.8 days,respectively.When applied as foliage spray at the rates of recommended dosage and the twice-recommended dosage,the final residue of famoxadone ranged from(0.048)~0.406 mg·kg~(-1)and 0.057~0.539 mg·kg~(-1)in apple and soil respectively,and did not exceed the maximum residue limit 2 mg·kg~(-1) established by EU.According to the results,we recommend that 68.75% Equation contact water-dispersible granule(WG) was applied in apple as foliage spray three times at a dosage of 1 000 dilution factor with a safe interval of 28 days from harvest.