烟叶及土壤中砜嘧磺隆农药残留及消解动态研究

Residue and Dynamic Degradation of Rimsulfuron in Tobacco Leaf and Soil

[目的]研究砜嘧磺隆在烟草上使用后的残留行为及环境安全性。[方法]建立了利用HPLC-MS/MS技术检测烟叶及土壤中砜嘧磺隆残留量的方法。样品经过乙腈提取,N-丙基乙二胺(PSA)吸附剂净化,高效液相色谱-串联质谱检测,外标法定量。采用所建检测方法测定了GAP试验获得的烟草和土壤中砜嘧磺隆残留。[结果]在0.005~0.500 mg/kg的加标水平下,土壤和鲜烟叶中砜嘧磺隆的平均添加回收率分别为84.1%~95.8%、90.0%~94.2%,相对标准偏差分别为3.2%~6.4%、3.6%~7.3%,定量限均为0.005 mg/kg。在0.010~0.500 mg/kg的加标水平下,干烟叶中砜嘧磺隆的回收率为87.1%~90.1%,相对标准偏差为2.0%~8.9%,定量限为0.010 mg/kg。砜嘧磺隆在鲜烟叶中的原始沉积量为<0.005~0.041 mg/kg,在土壤中为<0.005~0.510 mg/kg,砜嘧磺隆在土壤中消解较快,理论半衰期为1.4~2.9 d;施药后70 d,烤后烟叶中农药残留量低于定量限。[结论]采用20%砜嘧磺隆可分散油悬浮剂防治烟草田杂草,于烟草移栽期喷雾施药1次,制剂用药量为90~105 g/hm^2(有效成分18~21 g a.i./hm^2),安全间隔期为70 d。

[Objective] The aim was to study the residual behavior and dissipation of rimsulfuron in tobacco and soil.[Method]The sample collected from the field experiment were extracted by acetonitrile,and cleaned up by dispersive solid phase extraction using N-propyl ethylenediamine（ PSA） as adsorbent,and detected by HPLC-MS/MS.[Result]The average recoveries of rimsulfuron at the level of 0. 005-0. 500 mg/kg in fresh tobacco leaf and soil were 84. 1%-95. 8% and 90. 0%-94. 2%; the relative standard deviation（ RSD） were 3. 2%-6. 4% and 3. 6%-7. 3%,respectively; and the quantitative limit（ LOQ） was 0. 005 mg/kg. The average recovery of rimsulfuron at the level of 0. 010-0. 500 mg/kg in cured tobacco leaf was 87. 1%-90. 1%; the RSD was 2. 0%-8. 9%; and the quantitative limit（ LOQ） was 0. 010 mg/kg. The initial deposition of rimsulfuron in fresh tobacco leaf was 〈0. 005-0. 041 mg/kg,and was 〈0. 005-0. 510 mg/kg in soil. The half-life of rimsulfuron in soil was 1. 4-2. 9 days,and the final residue in cured tobacco leaves was below 0. 010 mg/kg after the application of rimsulfuron for 7 days.[Conclusion] It is recommended to rimsulfuron applied at the stage of transplant to prevent weeds in tobacco fields with the dose of 18-21 grammer per hectare（ active ingredients）. The safe intervals is 70 days.