摘要:
为了评价吡虫啉在菜用大豆上使用后的残留行为及环境安全性,采用高效液相色谱法研究了菜用大豆中的残留与消解动态,并对其安全使用技术进行示范试验。结果表明,吡虫啉在菜用大豆上的原始沉积量因不同施药处理有所差异,残留消解动态符合一级动力学方程,不同施药处理的消解速率基本趋于一致,消解系数(︱k︱)=0.1863±0.0149,半衰期(DT50)为3.5～3.9 d,消解99%所需要的时间(T99)为22.9～26.0 d。在菜用大豆接近采收时,按常规施药方法,每667m2施用吡虫啉有效成分3.00g,施药1次的在施药后3 d残留量均1.0 mgkg-1,残留量平均为0.299 mgkg-1;间隔7 d连续施药2次的,在第2次施药后5 d的残留量均1.0mgkg-1,残留量平均为0.374 mgkg-1,产品质量安全水平均达到日本、美国的MRL要求。
Abstract:
To determine the changes in residue and environmental safety of imidacloprid application on soybeans used as a vegetable,HPLC and field experimentation were conducted.At the same time,a safe application method of the insecticide was developed.The result showed that(a) the imidacloprid degradation followed first order kinetic,(b) the initial imidacloprid residue amount varies with method of application,(c) the degradation rates were basically the same,(d) the degradation coefficient,(︱k︱),was 0.186 3±0.014 9,(e) the DT50 was 3.5-3.9 d,and(f) the T99 was 22.9-26.0 d.The soybeans were sprayed with 3.00 g of effective imidacloprid per 667 m2 near time of harvest.The insecticide residues,3 days after the application,were all less than 1.0 mgkg-1,averaging 0.299 mgkg-1.When the spray was applied twice at 7d interval,the residues were all less than 1.0 mgkg-1 averaging 0.374 mgkg-1,5d after the second spray.The residue levels on the soybeans were all below the Japanese or American MRL requirements.
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