茚虫威在豇豆中残留动态及安全使用技术研究

Residual Dynamics and Safe Usage Technologies of Indoxacarb in Cowpea

采用气相色谱(GC-ECD)分析法,研究15%茚虫威(安打)乳油在豇豆中的残留消解动态和安全使用技术。该方法最小检出量为0.01ng,最低检出浓度为0.005mg/kg;添加回收率分别为84.7%～92.8%,RSD为3.43%～5.27%。残留消解动态表明,茚虫威在豇豆中的原始沉积量间隔7d连续施用2次>施用1次;残留消解动态均符合一级动力学方程,茚虫威施用1次的消解动态方程为C=2.7180·e-0.2500t,半衰期(DT50)为2.8d,消解99%所需时间T0.99为18.4d;施用2次的消解动态方程为C=2.3712·e-0.2404t,DT50为2.9d,T0.99为19.2d。在豇豆采收期施用茚虫威有效成分48.21g/hm21次,或间隔7d连续施用2次,在末次施药后11d采集豆荚样品检测,残留量均<0.2mg/kg,平均残留量分别为0.103mg/kg和0.111mg/kg,产品质量安全水平符合日本最高残留限量(MRL)的要求。

The residual degradation and safe usage technologies of 15% indoxacarb oil in cowpea were studied by gas chromatography analyzing. The results of determination showed that the LOD of this method was 0.01ng, LOQ was 0.005mg/kg; The average append recovery in cowpea ranged from 84.7%-92.8% and RSD ranged from 3.43%-5.27%. The results of residual degradation dynamics experiments showed that the original sediment of indoxacarb sprayed twice at 7d intervals in cowpea were more than that of once. The residual degradation dynamics of indoxacarb were followed first order kinetic equation. When it was sprayed once, the degradation dynamics equation was C=2.7180·e^-0.2500t, DT50 was 2.8d and T0.99 was 18.4d. While it was twice, the degradation dynamics equation was C=2.3712·e^-2404t, DT50 was 2.9d and T0.99 was 19.2d. When close to harvest, sprayed once with 48.21 g/hm^2 of indoxacarb or twice at 7d intervals, the last residues in cowpea were less than 0.2mg/kg lld after applied, the average residue was 0.103mg/kg and 0.111 mg/kg respectively. The quality safety of products fulfils the MRL of Japan.