啶虫脒在宁夏甘草和根际土壤中的残留及消解动态

Residues and degradation dynamics of acetamiprid in Glycyrrhiza uralensis and rhizospheric soil in Ningxia

为制定甘草规范化种植中农药啶虫脒在甘草上的安全使用技术标准,采用田间试验方法和高效液相色谱法,测定了啶虫脒在甘草和根际土壤中的残留及消解动态.甘草样品经乙腈提取,土样经丙酮提取,均采用柱层析法净化和DAD检测器检测.结果表明:在本文设定的色谱条件下,样品的最小检出量为2 ng,最小检出质量分数为0.01×10^(-6).在0.1～10.0μg/mL的范围内,啶虫脒峰面积与进样量之间有良好的线性关系.甘草中啶虫脒的添加回收率为85.4%～97.4%,相对标准差为4.76%～6.40%;甘草对应根际土壤中啶虫脒的添加回收率为89.9%～99.1%,相对标准差为2.98%～5.56%,符合农药残留分析要求.药后甘草根及土壤中啶虫脒的消解动态完全符合一级反应动力学方程式,残留消解速率较快,半衰期分别为6.82,8.13天.参照韩国规定的啶虫脒在中药材黄芪上的最大残留限量(0.1×10^(-6)),建议3%啶虫脒乳油依推荐剂量一次施药后在甘草中的安全间隔期不得少于39天.

In order to set up safe using standard for acetamiprid in Glycyrrhiza uralensis during the normal planting of Glycyrrhiza uralensis,field experiment and high performance liquid chromatography were used to determine the residues and degradation dynamics of acetamiprid in Glycyrrhiza uralensis and rhizospheric soil.The samples of Glycyrrhiza uralensis and soil were extracted with acetonitrile and acetone,respectively, and they were all purified with column chromatography and determined with DAD.The results show that the minimum determined quantity was 2 ng and the minimum determined concentration was 0.01×10^（-6） with the condition of the paper set up.There were good linear relation between the peak area of acetamiprid and the sample size in the range from 0.1 to 10.0μg/mL.The fortified recoveries of acetamiprid was between 85.4% to 97.4%,Relative standard deviation was between 4.76%and 6.40%,the fortified recovery of rhizospheric soil was between 89.9%and 99.1%,and relative standard deviation was between 2.98%and 5.56%,which all conformed completely to the requirements of pesticide residue analysis.The degradation dynamics of acetamiprid in Glycyrrhiza uralensis and rhizospheric soil conformed completely to the equation of first-class reaction kinetics.The speed of residue-occurrence and degradation were much more rapid,and the half-lives were 6.82 and 8.13 days,respectively.Refering to the Korean rule concerning the maximum residue limits （0.1×10^（-6）） of acetamiprid in astragalus root,the safe interval of acetamiprid 3%with recommended one-time dosage in Glycyrrhiza uralensis should be more than 39 days from harvest.