苯醚甲环唑和嘧菌酯在石榴中的残留行为与合理使用评价

Residue Dynamics and Reasonable Use of Difenoconazole and Azoxystrobin in Pomegranate

采用田间小区方法进行苯醚甲环唑和嘧菌酯在石榴中的最终残留和消解动态试验,为两者的合理使用及其安全性评价提供科学依据。样品经乙腈提取,固相萃取法净化,GC-ECD进行测定。苯醚甲环唑和嘧菌酯在石榴中的降解规律符合一级动力学指数模型,消解半衰期分别为2.7~7.7 d和2.3~5.9 d。325 g/L苯甲·嘧菌酯悬浮剂在有效成分用量216.7~325.1 mg/kg,施药3~4次,施药间隔7~10 d,采收间隔21 d时,苯醚甲环唑在石榴籽中的残留量<0.02 mg/kg,嘧菌酯在石榴籽中的残留量≤0.050 mg/kg。膳食风险评估结果表明:两者对8类人群的膳食摄入风险均低。采用325g/L苯甲·嘧菌酯悬浮剂防治石榴叶斑病,建议有效成分最高用药量为216.7 mg/kg,每季宜施药2~3次,安全间隔期21 d。

To evaluate the residue dynamics of difenoconazole and azoxystrobin in pomegranate, and provide the scientific basis for rational use and safety assessment, the field experiments were carried out in 2013-2014. The samples were extracted with acetonitrile, cleaned up by Florisil extract column and detected by GC-ECD. The half-lives of difenoconazole and azoxystrobin in pomegranate were 2.7-7.7 d and 2.3-5.9 d, respectively. The residues of difenoconazole in pomegranate were less than 0.02 mg/kg, the residues of azoxystrobin were less than or equal to 0.050 mg/kg. The results indicated that the RQ and RP were under 1 and 100%, respectively. The preharvest interval of difenoconazole ＋ azoxystrobin 325 g/L SC was 21 d, it could be sprayed 2-3 times, and the highest dose was 216.7 mg/kg.