Abstract:

【Objective】 To explore the storage stability and residual behavior of dinotefuran and its metabolite UF and DN on rice, and carry out the standard residue field test of furoxime on rice in Shanghai, Anhui and other 12 places.【Methods】 The samples were extracted by acetonitrile acetate, and the supernatant was purified by dispersed solid phase extraction and detected by membrane, liquid chromatography-mass spectrometry.【Results】 The results showed that the average recovery rate of furoxime in rice was 86.8%-97.5%, the relative standard deviation (RSD, n=5) was 1.6%-6.9%, and the average recovery rate of UF was 9%. The average recovery-DN was 86.1%-97.8%, the relative standard deviation (RSD, n=5) was 1.5%-7.0%, and the quantitative limit (LOQ) was 0.05. The minimum detection was 2.5×10 ^-11. The final residue test showed that: 20% furoxime water dispersible granule, the dosage of preparation was 40 g /hm² (120 ga.i/hm²), the application time was 2 times, the application interval was 10 d, the harvest interval was 14 d and 21 d, residue of furoxime in straw and rice was less than 0.5 mg/kg; and the residue of metabolites in straw and rice was less than 0.2 mg/kg, which respectively met the requirements of our country for the residue limit of furoxime in rice. Stability test also showed that furoxime and its metabolites were stored stably in -20℃ refrigerator.【Conclusion】 The data measured by this experimental method are in line with the requirements of China's limit of the residue of pyridosamine in rice, the storage of experimental drugs in the refrigerator at -20℃ is stable, indicating that the test data is effective, therefore, according to China's maximum residual limit on rice, it is recommended that 20% of the water dispersants of pyrethroids, the dosage is 40 g preparation / 667m² (120 g a.i/hm²), applied in rice most twice, a safe interval is 10 days, and a safe harvesting interval is 14 days.

Key words: furoxime; final residue; stability test; rice

摘要：

【目的】研究呋虫胺及其代谢物1-甲基-3-[(3- 四氢呋喃)甲基]脲 (1-methyl-3-[(3- tetrahydrofuran) methyl] urea, UF)及1-甲基-3-[(3-四氢呋喃)甲基] 二氢胍盐 (1-methyl-3 -[(3-tetrahydrofuran) methyl] dihydroguanidine, DN)在水稻上的储存稳定性及其残留行为。【方法】在上海、安徽等12地开展呋虫胺在水稻上的规范残留田间试验。样品经乙酸乙腈提取,上清液经分散固相萃取净化后,过膜,液相色谱-质谱联用仪检测。【结果】在0.05~0.5 mg/L的添加水平范围内,水稻中呋虫胺的平均回收率在86.8%~97.5%,相对标准偏差(RSD,n=5)为1.6%~6.9%;UF的平均回收率在91.9%~96.4%,相对标准偏差(RSD,n=5)为1.6%~6.1%;DN的平均回收率在86.1%~97.8%,相对标准偏差(RSD,n=5)为1.5%~7.0%,定量限(LOQ)均为0.05 mg/kg,最小检出量均为2.5×10^-11 g。最终残留试验表明:20%呋虫胺水分散粒剂,用药量为制剂40 g/hm²(120 g a.i/hm²),施药2次,施药间隔10 d,采收间隔期14和21 d,分别采收稻谷(稻壳、糙米)和秸秆,秸秆、稻谷中呋虫胺的残留量均小于0.5 mg/kg;秸秆、稻谷中代谢物DN残留量均小于0.2 mg/kg;秸秆、稻谷中代谢物UF残留量均小于0.2 mg/kg。稳定性试验也表明:呋虫胺及其代谢物在-20℃冰箱储藏稳定。【结论】测得数据均符合我国对水稻中呋虫胺残留限量的要求,实验药品在-20℃冰箱储藏稳定,检测数据有效,20%呋虫胺水分散粒剂,用药量为制剂40 g制剂 /667m²(120 g a.i/hm²),于水稻最多施药2次,安全间隔期10 d,采收安全间隔14 d。

关键词: 呋虫胺, 最终残留, 稳定性试验, 水稻