Objective] The aim was to study method for determining diafenthiuron residue in vegetables, to provide reference basis for safety uti-lization.[Method] Using QuEChERS pretreatment technology and LC -MS/MS analysis method, detection method for diafenthiuron in cabbage and cauliflower was established, field experiment was carried out to study digestion dynamics of diafenthiuron residue in cabbage and cauliflower. [Result] Within the range of 0.01 -1.00 mg /kg, recovery rate in cabbage samples was between 79.4% -86.8%, variation coefficient was 4.6% -7.2%; recovery rate was between 83.8% -88.5% in cauliflower samples, variation coefficient was 5.1% -7.7%, detection limit was 2.5 μg/kg.The field residue test showed that degradation of diafenthiuron in cabbage and cauliflower was accord with dynamics curve , the half-life period was 2.2 and 3 .2 d respectively.[Conclusion] The residue determination for diafenthiuron in cabbage and cauliflower is sensitive , reproduciable and is in accordance with the requirements of pesticide residues detection.Combined with the MRL value of China and abroad, safety interval of diafenthiuron in cabbage and cauliflower is 7 d, the use of diafenthiuron should be careful in export vegetables.%[目的]研究丁醚脲在蔬菜中的残留检测方法和田间消解动态，为丁醚脲在蔬菜上的使用安全提供参考依据。[方法]结合QuEChERS 前处理技术和 LC －MS／MS 分析技术，开发建立丁醚脲在甘蓝和花菜中的检测方法，并采用田间试验方法研究丁醚脲在甘蓝和花菜中的残留消解动态规律。[结果]试验表明，在0．01～1．00 mg ／kg 添加水平范围内，甘蓝样品中的添加回收率在79．4％～86．8％，变异系数为4．6％～7．2％，花菜样品中的添加回收率在83．8％～88．5％，变异系数为5．1％～7．7％，检出限为2．5μg／kg。田间残留试验表明，丁醚脲在甘蓝和花菜中降解符合动力学曲线，丁醚脲在甘蓝和花菜中的消解半衰期分别为2．2和3．2 d。[结论]该试验方法进行甘蓝和花菜中丁醚脲残留测定，灵敏度高，重现性好，符合农药残留检测的要求。消解动态和最终残留试验结果结合我国和国外 MRL 值，建议推荐用量的丁醚脲在甘蓝和花菜中的安全间隔期为7 d，出口蔬菜中谨慎使用丁醚脲。
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