印楝素在甘蓝及土壤中的消解动态

Degradation dynamics of azadirachtin in cabbage and soil

【目的】甘蓝Brassica oleracea生长期施用w为0.3%的印楝素乳油,检测印楝素在甘蓝和土壤中的残留及消解动态。【方法】印楝素在0.05~5.00 mg·kg^(-1)水平范围内取0.1、0.5、1.0 mg·kg-1添加,样品中的印楝素经乙腈超声波辅助提取,弗罗里硅土固相萃取柱净化,高效液相色谱(HPLC)检测,外标法定量。【结果】印楝素在甘蓝中的平均回收率为88.52%~93.21%,相对标准偏差为2.75%~3.55%;在土壤中平均回收率为90.69%~93.32%,相对标准偏差为2.09%~3.46%。印楝素在甘蓝中的残留半衰期为0.89 d,在土壤中的残留半衰期为2.40 d。【结论】印楝素属易降解农药。该施药方法安全可靠,值得借鉴。

【Objective】To identify the residual and degradation dynamics of azadirachtin in cabbage and soil after spraying 0.3%azadirachtin emulsifiable concentrate during the growth period of cabbage （Brassica oleracea）.【Method】Azadirachtin was added with three concentrations of 0.1,0.5 and 1.0 mg·kg^-1 within the range from 0.05 to 5.00 mg·kg^-1. Azadirachtin was extracted from cabbage and soil using acetonitrile assisted with ultrasonic, purificated using a florisil solid phase extraction column, detected by HPLC and quantified by external standard method.【Result】The average recovery rates of azadirachtin in cabbage ranged from 88.52% to 93.21% with relative standard deviations ranging from 2.75% to 3.55%, and the average recovery rates in soil were ranged from 90.69% to 93.32% with relative standard deviations ranging from 2.09% to 3.46%.The half lives of azadirachtin in cabbage and soil were 0.89 and 2.40 d respectively.【Conclusion】Azadirachtin is an easily degradable pesticide. Application of 0.3% azadirachtine mulsifiable concentrate is safe and recommended.