Dynamic Analysis of Difenoconazole Residue in Tomatoes and Soil

A field experiment was conducted to reveal the dissipation rate and residue analysis of difenoconazole in tomatoes and soil.The difenoconazole was determined by UPLC-MS/MS.The average recoveries of difenoconazole were 90.3%-107.1% in tomatoes and 80.1%-104.7% in soil with relative standard deviations of 0.7%-7.8% and 7.2%-9.1%,respectively.Difenoconazol degraded more rapidly in tomatoes than in soil.The half-lives in tomatoes and soil were 3.3-3.8 d and 19.9-22.4 d in Shandong Province,and 3.3 d and 13.1-18.8 d in Henan Province,respectively.When the tomatoes were treated by 10% difenoconazole,ME at recommended dose twice,on day 3 after the last application the final residue of difenoconazole in the tomatoes was below 0.158(mg/kg),which was lower than the maximum residue limit(MRL,0.5(mg/kg)) for Japan and Australia.These results suggested that difenoconazole was a kind of low residual,easily dissipated fungicide.