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为研究2.5%溴氰菊酯乳油在大白菜和土壤中的残留消解动态,对大白菜和土壤喷施相应药剂后进行取样。样品经石油醚或石油醚/丙酮(V/V 1:1)提取,液液分配净化,用气相色谱电子捕获检测器检测。溴氰菊酯在白菜中的平均回收率在104.09%-112.28%之间,变异系数为2.66%-4.35%;在土壤中的平均回收率在103.67%-108.80%之间,变异系数为1.66%～3.45%,准确度和精密度均达到了《农药残留试验准则》的规定。消解动态试验和最终残留试验结果表明:溴氰菊酯在白菜和土壤中的消解较快,在白菜和土壤中的半衰期分别为6.7 d和6.4 d。当溴氰菊酯分别在高剂量和低剂量下施药三次和四次后,药后21 d收获白菜和土壤中的残留量均低于最低检出浓度(LOD)。
In order to study the dynamics of residue digestion of 2.5% deltamethrin EC in Chinese cabbage and soil, the cabbage and soil were sprayed with the corresponding chemicals and then sampled. Samples were extracted with petroleum ether or petroleum ether / acetone (V / V 1: 1) and the liquid was partitioned and purified by gas chromatography electron capture detector. The average recovery of deltamethrin in cabbage was between 104.09% and 112.28%, the coefficient of variation was 2.66% -4.35%. The average recoveries in soil ranged between 103.67% and 108.80%, and the coefficient of variation was 1.66% ~ 3.45%, the accuracy and precision have reached the “pesticide residue test guidelines” requirements. The results of dynamic test and final residue test showed that deltamethrin was rapidly digested in cabbage and soil, and the half-lives in cabbage and soil were 6.7 d and 6.4 d, respectively. When deltamethrin was applied three times and four times under high dose and low dose respectively, the residues of cabbage and soil were lower than the lowest detectable concentration (LOD) after 21 days.