嘧霉胺和乙霉威在大葱中的残留消解动态

Field residue decline study of pyrimethanil and diethofencarb in welsh onion

建立了大葱中嘧霉胺和乙霉威残留的检测方法,并测定了嘧霉胺和乙霉威在春季大葱中的残留消解动态和最终残留量。大葱样品经乙腈提取,SAX/PSA固相萃取柱净化,气相色谱-质谱选择离子(GC/MS/SIM)检测。结果表明,建立的大葱中嘧霉胺和乙霉威残留量检测方法在0.001～0.1mg/kg和0.01～0.1mg/kg水平的平均添加回收率为97.8%～107.2%,相对标准偏差为2.7%～7.4%,嘧霉胺和乙霉威的检出限分别为0.0003和0.003mg/kg,方法的定量限分别为0.001和0.01mg/kg。田间残留试验结果表明,嘧霉胺和乙霉威在大葱中消解较快,半衰期分别为4.1和3.1d,药后14d消解率均达90%以上;26%嘧霉.乙霉威可湿性粉剂(嘧霉胺和乙霉威质量比为10∶16)按推荐高剂量1800g/hm2(嘧霉胺有效成分180g/hm2,乙霉威有效成分288g/hm2)和2倍剂量3600g/hm2对水喷雾2～3次,末次施药后7,14,21d,嘧霉胺在大葱中的最终残留量为0.007～0.560mg/kg,乙霉威在大葱中的最终残留量为ND～0.394mg/kg,均低于日本规定的最大残留限量(MRL)2.0和5.0mg/kg。

The field residue decline study and final residue trials of pyrimethanil and diethofencarb in spring welsh onion in Shandong Province,China,were designed.Welsh onion samples were extracted with acetonitrile and the extracts were cleaned up by SPE column filled with mixed type SAX-PSA,followed by determination with GC-MS at selected ion monitor mode(SIM).The fortified recovery at level of 0.001 to 0.1 mg/kg and 0.01 to 0.1 mg/kg ranged from 97.8% to 107.2%,with relative standard deviation of 2.7% to 7.4%.The...