植物源杀菌剂1%蛇床子素水乳剂在黄瓜和土壤中的残留动态

Dynamics of Botanical Fungicide 1% Osthol EW Residue in Cucumber and Soil

采用田间试验方法,探讨蛇床子素在黄瓜和土壤中的消解动态和最终残留。样品经甲醇和丙酮提取,石油醚液-液分配,固相萃取小柱净化后,进行高效液相色谱分析。仪器最小检出量（LOD）为0.2 ng,在黄瓜和土壤中的最低检出质量分数（LOQ）均为0.02 mg/kg。蛇床子素在黄瓜中的平均回收率为88.80%-93.61%,变异系数为1.94%-4.92%;在土壤中的平均回收率为90.74%-94.55%,变异系数为3.20%-6.45%。田间试验结果显示,蛇床子素消解较快,在南京和山东两地黄瓜中降解半衰期分别为0.76 d和0.87 d,土壤中降解半衰期分别为1.12 d和1.15 d。在黄瓜上使用1%蛇床子素水乳剂,按照推荐剂量的1.5倍4 500 g/hm2和推荐剂量3 000 g/hm2喷雾5-6次,距最后一次施药1 d,黄瓜中的残留量为0.11-0.43 mg/kg,土壤中的残留量为0.31-0.77 mg/kg,均小于1.00 mg/kg。以上数据表明,蛇床子素在黄瓜和土壤中属低残留、易降解农药。

A field experiment was conducted to reveal the dynamics of osthol residue in cucumber and soil.The osthol was extracted from the cucumber and soil by methanol and acetone,followed by liquid-liquid partition with petroleum ether,purification with solid phase extraction（SPE）,and quantification with high-performance liquid chromatography（HPLC）.The limit of detection（LOD） was 0.2 ng,while the limits of quantification（LOQ） of osthol both in cucumber and soil were 0.02 mg/kg.The average recoveries and coefficient of variations of osthol in cucumber were 88.80%-93.61%,1.94%-4.92%,respectively,and were 90.74%-94.55%,3.20%-6.45% for soil samples,respectively.The results of two-year field experiment showed that the half-lives of osthol were in a range of 0.76-0.87 d in cucumber and 1.12-1.15 d in soil.When the cucumber were treated with 1% osthol EW of 4 500 g/hm2 and 3 000 g/hm2 for five to six times,the final residues of osthol were 0.11-0.43 mg/kg in cucumber and 0.31-0.77 mg/kg in soil one day after treatment,which implied that osthol belonged to non-persistent pesticides and was easy to be degraded（T1/230 d）.