吡虫啉在海南豇豆及土壤中的消解动态研究

Degradation Dynamics of Imidacloprid in Hainan Cowpea and the Soil

建立了豇豆、土壤中吡虫啉测定高效液相色谱法．并研究吡虫啉在海南豇豆和其种植土壤中的消解动态以及在豇豆中的最终残留。结果表明：方法回收率为78％-89％，在0．05～5μg／mL线性关系良好，相对标准偏差（RSD）〈7％，最低定量限0．01μg/L，方法满足检测工作要求。吡虫啉在豇豆和土壤中的半衰期分别为2．9、5．1d。以1．5倍推荐剂量一次喷施农药2．5d后吡虫啉残留量小于0．5μg/g。吡虫啉在土壤中半衰期较短，属于易降解农药；分别以1．5、2倍推荐剂量3次施药，每次施药间隔2d，自然降解4、6d后残留量均低于0．5μg／g。

The HPLC method for imidacloprid in soil and cowpea was developed. The degradation dynamics of the imidacloprid in the soil and cowpea and the terminal residue in the cowpea were studied. The method recovery ranged 78% to 89% and the linear relationship was good from 0.05 to 5 μg/mL with a relative standard deviation less than 7%. The method limit of quantification was 0.01 μg/mL. The method could cover the detection requirement. The half-life of the imidaeloprid in the soil and cowpea was 2.8 d and 3.7 d, respectively. The residue of the imidacloprid in the cowpea was less than 0.5μg/g 2.5 days later when 1.5 times of the recommended dose of imidacloprid was sprayed. The half-life of the imidacloprid was short, which belongs to the easy degradation pesticide. The cowpea was sprayed once per 2 days for three times, respectively with 1.5 times and 2 times of the recommended dose. The results showed that the imidaeloprid residue in the cowpea were less than 0.5μg/g, respectively 4 days and 6 days later.