烟叶及土壤中砜嘧磺隆农药残留及消解动态研究

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。

Residue and Dynamic Degradation of Rimsulfuron in Tobacco Leaf and Soil

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 reconmmended to rimsulfuron applied at the stage of transplant to prevent weeds in tobacco fields with the dose of 18-21 gammer per hectare (active ingredients).The safe intervals is 70 days.