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[目的]明确氯氰菊酯和毒死蜱在龙眼上的残留行为,为氯氰菊酯和毒死蜱的合理使用及其安全性评价提供科学依据。[方法]采用田间小区方法进行氯氰菊酯和毒死蜱在龙眼环境中的消解动态试验。样品采用甲醇提取、弗罗里硅土固相萃取柱净化,气相色谱测定。[结果]龙眼中氯氰菊酯和毒死蜱添加质量浓度为0.01~1 mg/L时,其平均添加回收率分别为85.15%~87.84%、84.87%~85.96%;相对标准偏差分别为2.45%~7.58%、2.57%~5.63%。检出限(LOD)为0.005 mg/kg;定量限(LOQ)为0.01 mg/kg。氯氰菊酯和毒死蜱在龙眼中的半衰期分别为4.75~8.27、3.17~6.87 d。采用风险商方法进行评估,喷施氯氰菊酯和毒死蜱后0~7 d内的龙眼对2~4岁、18~30岁和60~70岁人群的风险都很低。[结论]建议用氯氰·毒死蜱乳油防治龙眼蒂蛀虫时,质量浓度应控制在0.391 5~0.783 g/L,每株使用剂量为0.587 3~1.174 5 g,安全间隔期设定为7 d,对作物和人类健康都是安全的。
[Objective] The research aimed to clarify the residual behavior of cypermethrin and chlorpyrifos on longan, and provide a scientific basis for the rational use of cypermethrin and chlorpyrifos and their safety evaluation. [Method] The dynamic test of digestion of cypermethrin and chlorpyrifos in longan environment by field plot method. The samples were extracted with methanol and purified with Florisil SPE, and determined by gas chromatography. [Result] The results showed that the average recoveries of cypermethrin and chlorpyrifos in the longan were 85.15% -87.84% and 84.87% -85.96%, respectively, with the relative standard deviations of 2.45% -7.58% when they were added at the concentration of 0.01-1 mg / L. 2.57% ~ 5.63%. The limit of detection (LOD) was 0.005 mg / kg; the limit of quantification (LOQ) was 0.01 mg / kg. The half-lives of cypermethrin and chlorpyrifos in longan were 4.75-8.27 and 3.17-6.87 d, respectively. The risk-based method was used to assess the risk of longan within 0-7 days after spraying cypermethrin and chlorpyrifos at low risk for people 2-4 years of age, 18-30 years of age and 60-70 years of age. [Conclusion] The proposed concentration of chlorpyrifos and chlorpyrifos EC could be controlled from 0.391 5 to 0.783 g / L, with the dosage of 0.587 3 to 1.174 5 g per plant and the safety interval of 7 d. It is safe for crops and human health.