螺螨酯在苹果和土壤中的残留分析及消解 动态研究

Degradation dynamics and residues analysis of spirodiclofen in apple and soil

中文关键词:  螺螨酯  消解动态  残留  苹果  土壤

英文关键词:spirodiclofen  dissipation dynamics  residue  apple  soil

中文摘要:

      目的 研究螺螨酯通过喷雾施药方式在苹果和土壤中的残留水平及消解动态, 制定螺螨酯悬浮剂防治苹果叶螨的安全间隔期。方法 在北京、安徽及山东3地进行农药残留的田间消解试验。样品采用乙腈提取, 经弗罗里硅土固相萃取柱净化, 气相色谱-电子捕获检测器(gas chromatography-election capture detector, GC-ECD)检测, 外标法定量。结果 在添加水平为0.01~2 mg/kg范围内, 螺螨酯在苹果及土壤中的添加回收率为91.6%~104.6%, 相对标准偏差为1.4%~4.2%; 方法定量限为0.01 mg/kg。在北京、安徽及山东3地试验中, 螺螨酯在苹果及土壤中的消解动态符合一级动力学指数模型, 在苹果中的半衰期为11~19 d, 在土壤中的半衰期为1.4~4.1 d。按照推荐高剂量及其1.5倍剂量施药1次和2次, 在距末次施药间隔为30、40、50 d苹果样品中, 螺螨酯的残留量均低于0.071 mg/kg。结论 参照国际食品法典、美国及欧盟规定的螺螨酯在苹果上的农药最高残留限量均为0.8 mg/kg, 在推荐施药条件下, 采收间隔30 d之后的苹果是安全的。

英文摘要:

      Objective To formulate the scientific basis for the reasonable dosage and the pre-harvest interval (PHI) on controlling apple red mite with spraying application based on the investigation of the degradation dynamics of spirodiclofen in apple and soil. Methods The residual trials of spirodiclofen in apple were carried out in Beijing, Anhui and Shandong Province. The samples were extracted with acetonitrile, purified by florisil solid-phase extraction (SPE) column and determined by gas chromatography equipped with electron capture detector (GC-ECD). The external standard method was used for quantitation. Results The average recoveries spiked at the levels of 0.01~2 mg/kg were 91.6%~104.6% in apple and soil with the relative standard deviations (RSD) of 1.4%~4.2%. The limit of quantification of this method was 0.01 mg/kg. The degradation dynamic equations of spirodiclofenin apple and soil were fitted the first order reaction dynamic equations, and the degradation half-lives of spirodiclofen were 11~19 d in apple and 1.4~4.1 d in soil. The final residues of spirodiclofen in apple were below 0.071 mg/kg at the end of the time interval of 30, 40 , 50 d after the last application with the 1 and 1.5 times of high level of recommend does. Conclusions Considering about the maximum residue limit (MRL) of 0.8 mg/kg set by Codex Alimentarius Commission, United States of America and European Union, it is suggested that apple is safe for human after spraying spirodiclofen for 30 d under the application dosage and times of spirodiclofen.