苯醚甲环唑在番茄和土壤中的残留动态研究

采用田间试验方法研究苯醚甲环唑在番茄和土壤中的残留与降解动态，应用超高效液相色谱-串联四级杆液质联用法(UPLC-MS/MS)进行定性和定量分析. 结果表明，苯醚甲环唑在番茄中的平均回收率为90.3%～107.1%,变异系数为0.7%～7.8%；在土壤中的平均回收率为80.1%～104.7%，变异系数为7.2%～9.1%. 动态研究结果表明:苯醚甲环唑在番茄中的降解比在土壤中快，在山东和河南两地番茄中的降解半衰期分别为3.3～3.8和3.3 d；在土壤中的降解半衰期分别为19.9～22.4和13.1～18.8 d. 10%苯醚甲环唑微乳剂在番茄上按照推荐剂量最多施药2次，采收期距最后一次施药3 d，番茄中苯醚甲环唑残留量小于0.158 mg/kg. 低于日本和澳大利亚规定的最高残留限量(MRL，0.5 mg/kg)，说明苯醚甲环唑为低残留、易降解农药. 

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 suggestedthat difenoconazole was a kind of low residual, easily dissipated fungicide.