12.5%腈菌唑乳油在梨和土壤中的残留分析方法及残留动态研究

Study on the Method of Residue Analysis and the Residue Dynamics of Myclobutanil 12.5%EC in Pear Fruit and Soil

研究了腈菌唑在梨和土壤中的残留分析方法及其残留动态。样品用甲醇提取,中性氧化铝柱净化,气相色谱（ECD）测定。腈菌唑的最低检出量：2.5×10^-11g;最低检出浓度：梨和土壤分别为0.005和0.003 mg/kg。添加回收率为80.80%-93.81%,相对标准偏差为1.87%-4.96%,符合农药残留分析要求。试验结果表明,腈菌唑在梨中消解较快,土壤中相对缓慢,半衰期分别为2.86-4.75和15.79-24.17 d;末次施药距收获间隔7 d,梨中腈菌唑残留量均低于0.500 mg/kg,该药按推荐剂量使用是安全的。

An method of residue analysis and residue dynamics of myclobutanil in pear and soil were studied. Samples were extracted from pear and soil with methanol, and cleaned up by a column made up of neutral alumina, then determined by GC with ECD detector. The minimum detectable quantity of myclobutanil was 2.5 × 10^-11 g,the minim umdetectable concentration of myclobutanil in pear and soil sample was 0.005 and 0.1303 mg/kg. The average recoveries and coefficients of variation of the method were 80.80% - 93.81 % and 1.87 % - 4.96% respectively. The result showed that myclobutanil degraded rapidly in the pear,but lowly in the soil relatively.The half-life of myclobutanil in the former was 2.86-4.75 d and in the latter was 15.79- 24.17 d.And the last application was done in the 7th day before harvesting,the residue of myclobutanil in the harvested pear was lower than 0.5 mg/kg, demonstrating that it was safe to apply myclobutanil in pear with the recommended rate.