吡氟酰草胺在水稻上的消解及残留

Dissipation and Residues of Diflufenican in Rice

农药在作物上的消解和最终残留量是评价其使用安全性的重要指标。在我国不同水稻种植区域进行田间试验,采用高效液相色谱-串联质谱法,测定吡氟酰草胺在水稻上的消解规律和最终残留量。结果表明:吡氟酰草胺在水稻植株、稻壳和糙米中的平均回收率分别为90.3%~102.7%、78.0%~96.0%和92.7%~97.9%,相对标准偏差分别为1.0%~4.8%、4.4%~6.7%和1.4%~4.6%。吡氟酰草胺在水稻植株中降解半衰期为0.6~9.7 d;在水稻上按有效成分量150~225 g/hm^2使用1次,收获期时,水稻植株中的最终残留量<0.01 mg/kg,稻壳和糙米中的最终残留量均<0.005 mg/kg。根据试验结果,建议我国制定吡氟酰草胺在糙米中的最大残留限量为0.01 mg/kg。

The dissipation kinetics and final residues of pesticides in crops are crucial factors to evaluate the safety of pesticide application.In this study,the dissipation and final residues of the herbicide diflufenican in rice were investigated under field conditions in different rice cultivation areas in China using high-performance liquid chromatography-tandem mass spectrometry(HPLC-MS/MS).The results showed that mean recoveries of diflufenican from rice plant,rice hull and brown rice were 90.3%-102.7%,78.0%-96.0%and 92.7%-97.9%,respectively,and the corresponding relative standard deviations(RSD)were 1.0%-4.8%,4.4%-6.7%and 1.4%-4.6%,respectively.Half-lives of diflufenican in rice plant were in the range of 0.6-9.7 d.At harvest time,the residues of diflufenican in rice plant were lower than 0.01 mg/kg,and the values in rice hull and brown rice were less than 0.005 mg/kg when diflufenican was applied once at the dose of active ingredient of 150-225 g/hm^2.Based on the results,we suggested that the maximum residue limit(MRL)of diflufenican in brown rice could be established at 0.01 mg/kg in China.