【摘要】 【目的】研究吡虫啉在宁夏甘草及对应根际土壤中的残留及消解动态,为甘草规范化种植中吡虫啉安全使用标准的制定提供科学依据。【方法】采用灌根法,将10%吡虫啉可湿性粉剂依推荐剂量设1次和2次施药处理,于施药后不同时间采样,样品经盐酸溶液和甲醇提取及氯化钠溶液和二氯甲烷净化后,采用AgilentHPLC-1100高效液相色谱仪进行检测,对吡虫啉在甘草根部及其根际土壤中的添加回收率、残留动态进行分析。【结果】在设定的色谱条件下,样品的最低检出量为7.49×10-10g,最低检出浓度为3.75μg/kg。标准品不同进样量的测定结果表明,进样量为0.1～10μg/mL时,吡虫啉峰面积与进样量之间有良好的线性关系。甘草中吡虫啉的添加回收率为75.4%～90.4%,相对差标准为7.01%～8.13%,甘草对应根际土壤中吡虫啉的添加回收率为82.7%～93.6%,相对差标准为3.97%～5.11%,符合农药残留分析要求。残留检测结果表明,吡虫啉在甘草及对应根际土壤中的残留消解完全符合一级反应动力学方程式,其半衰期分别为5.44和5.63d;吡虫啉1次施药60d后,甘草中的残留低于最低检测浓度,土壤中的残留仅为0.009mg/kg;2次施药后53d,甘草中的残留量为0.013mg/kg,土壤中的残留量为0.095mg/kg。【结论】依据欧盟制定的"未纳入标准的农药均不得检出"的规定,建议10%吡虫啉可湿性粉剂在甘草上宜采用1次施药,且施药期距采收期的间隔时间不得少于60d。更多还原

【Abstract】 [Objective] In order to provide scientific basis for setting up a safe standard for Imidacloprid in Glycyrrhiza uralensis during the norm planting of G.uralensis,the research studied the residues and degradation dynamics of Imidacloprid in G.uralensis and rhizospheric soil in Ningxia.[Method] Using irrigate roots,Imidacloprid 10%(WP)was imposed one and two times with recommended dose,samples were extracted with hydrochloric acidl and methanol,purified with sodium chloride solution and dichloromethane and detected with DAD detector.[Result] With the condition of this paper chromatogram,the minimum detected quantity of samples was 7.49×10-10 g and the minimum detected concentration was 3.75 μg/kg.The results of Imidacloprid standard with different sample sizes showed that there was good linear relation between peak area of Imidacloprid and sample size in the concentration range from 0.1 μg/mL to 10 μg/mL,and the linear equation was Y=45.481X+0.854 5(r2=0.997 9).The fortified recoveries of Imidacloprid in G.uralensis was between 75.4% and 90.4%,RSD was between 7.01% and 8.13%;the fortified recoveries of Imidacloprid in rhizospheric soil was between 82.7% and 93.6%,RSD was between 3.97% and 5.11%,which conformed completely to the demand of analyzing pesticides residues.The residue results showed that the residues and degradation dynamics of Imidacloprid in G.uralensis and soil conformed completely to the equation of first-class reaction kinetic.They were CT=1.355 6e-0.127 5T(r=0.966 3)and CT=11.359e-0.123 1T(r=0.997 9)respectively,and its half-lives were 5.44 days and 5.63 days,respectively.[Conclusion] According to the rule European union made that the pesticises of no bringing into standard could not be checked out,the paper used Imidacloprid 10%(WP)with recommend dosage by irrigating roots,using one time,60 days later,the residue of Imidacloprid in G.uralensis less than the lowest detecting concentration(3.75 μg/kg)with the chromatogram condition the paper setted up.As a result,we recommended the safe interval of Imidacloprid 10%(WP)one time in G.uralensis should be more than 60 days from harvest.更多还原