二氯吡啶酸在油菜和土壤中的消解动态研究

摘要

In order to systematically study residues of clopyralid in rape and soil ,and promote the safety production ,a GC method was developed for quantitative analysis of clopyralid residue in rape and soil .Samples were extracted with ethyl acetate/petroleum ether (1∶1) ,after methyla-tion ,determined with GC-ECD ,and the degradation dynamics of clopyralid in rape and soil were studied .Under the optimum conditions ,the performance of the method was evaluated .The ave-rage recovery rate was 86 .3% -110 .1% ,and the relative standard deviation was 2 .4% -10 .6% . The degradation dynamics indicated that clopyralid degraded continuously and the curve of degra-dation dynamics followed the first-order kinetics equation .The half-lives of clopyralid in rape and soil were 2 .8 and 3 .5 days ,respectively ,which indicated that clopyralid should be classified as easily degradable agrochemical .%为了系统研究二氯吡啶酸农药在油菜及土壤中的残留消解动态，促进安全生产，利用气相色谱法建立了二氯吡啶酸在油菜和土壤中的残留分析方法，研究了二氯吡啶酸在油菜和土壤中的残留消解动态。油菜和土壤样品分别用乙酸乙酯＋石油醚（1∶1）溶液提取，经甲基化后，通过气相色谱-电子俘获检测器（GC ECD）测定，以面积外标法进行二氯吡啶酸的定量。结果表明，采用该方法测定，二氯吡啶酸在油菜和土壤中的平均回收率为86.3％～110.1％，相对标准偏差为2.4％～10.6％；二氯吡啶酸的残留量随施药后时间的延长而降低，消解动态曲线符合一级动力学方程，其在油菜和土壤中的半衰期分别为2.8d、3.5d，属于易降解性农药化合物。