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

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。

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

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 2.5×10-11g,the minim umdetectable concentration of myclobutanil in pear and soil sample was 0.005 and 0.003 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.