【摘要】 为了明确噻虫嗪在菜薹上使用后的残留行为，在6个省市开展了噻虫嗪在菜薹上的最终残留试验，在其中2个省份开展了消解动态试验。样品采用固相萃取柱净化，高效液相色谱-串联质谱法(HPLC-MS/MS)测定，外标法定量。结果表明：添加水平在0.01～1.0 mg/kg下，噻虫嗪及其代谢物噻虫胺在菜薹中的添加回收率为89%～102%和93%～100%，相对标准偏差为5.8%～8.5%和4.0%～9.5%，定量限(LOQ)为0.01 mg/kg。消解动态试验结果表明，山东和安徽两地噻虫嗪在菜薹上的降解半衰期分别为1.8 d和1.2 d;6个省市的最终残留试验结果显示，用药量56.25～84.375g a.i./hm~2，施药2～3次，药后10 d，收获的菜薹中噻虫嗪的残留量为<LOQ～0.125mg/kg。推荐25%噻虫嗪水分散粒剂防治菜薹上菜薹跳甲时，最高用药量56.25g a.i./hm~2，最多施药2次，推荐安全间隔期为7 d。更多还原

【Abstract】 In order to research the residue behavior of thiamethoxam in Chinese flowering cabbage,the final residue trials of thiamethoxam in Chinese flowering cabbage were carried out in five provinces and one city and the dissipation dynamic trials were carried out in two provinces.Samples were purified by solid phase extraction column,detected by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS),and quantified by external standard method.The results showed that the recoveries of thiamethoxam and its metabolite clothianidin were 89%-102%and 93%-100%,and the relative standard deviations (RSDs)were 5.8%-8.5%and 4.0%-9.5%,under the spiked levels of 0.01-1 mg/kg.The limit of quantification (LOQ)of thiamethoxam and its metabolite clothianidin was 0.01 mg/kg.The half-lives of thiamethoxam in Chinese flowering cabbage were 1.2 and 1.8 days in Shandong Province and Anhui Province,respectively.The results of final residue trials in five provinces and one city showed that the residue level of thiamethoxam in Chinese flowering cabbage was<LOQ～0.125mg/kg 10 days after application when the dosage was 56.25-84.375 g a.i./hm~2and the application was 2 to 3 times.The recommended application of 25%thiamethoxam WG to control Phyllotreta striolata in Chinese flowering cabbage was 2 times at the maximum dosage of 56.25 a.i.g/hm~2with a safe interval of 7 days.更多还原