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    氟醚菌酰胺与烯酰吗啉在烟叶中的残留及消解动态

    Decline Dynamics and Residues of Fluopimomide and Dimethomorph in Tobacco Leaves

    • 摘要: 为明确氟醚菌酰胺与烯酰吗啉两种农药在烟叶中的残留与消解动态,建立了高效液相色谱-串联质谱法(HPLC-MS/MS)检测方法。样品经乙腈提取,分散固相萃取净化后,采用Thermo Hypersil GOLD C18色谱柱分离,乙腈-0.1%甲酸水梯度洗脱,电喷雾正离子源(ESI+)雾化,多重反应监测(MRM)。结果表明,该方法线性关系良好,在0.02~20 mg/kg(鲜烟叶)与0.05~50 mg/kg(烤后烟叶)添加水平下,两种农药的平均回收率在86%~96%之间,相对标准偏差(RSD)在3.0%~9.4%范围内,该方法简便准确,可行性高。通过田间试验对氟醚菌酰胺与烯酰吗啉在烟叶上的消解动态进行研究表明,二者消解动态符合一级动力学模型,半衰期分别为7.2~15 d与5.3~12 d,均属于易降解农药;末次施药后21 d的最终残留量分别为0.045~7.2 mg/kg与0.058~4.0 mg/kg。本研究建立了烟叶中氟醚菌酰胺与烯酰吗啉的HPLC-MS/MS检测方法,探明了二者的消解动态及最终残留,为其在烟草上的合理安全使用提供了科学依据,并为二者在烟草上的最大残留限量(MRL)制定提供了数据支持。

       

      Abstract: To clarify the residues and decline dynamics of fluopimomide and dimethomorph in tobacco leaves, an efficient method using high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was established. Samples were extracted with acetonitrile and purified by dispersive solid-phase extraction. Then, they were separated by a Thermo Hypersil GOLD C18 column, eluted with acetonitrile-0.1% formic acid gradient, ionized by electrospray ionization source (ESI+), and monitored by multiple reaction monitoring (MRM). The results indicated that the method had a good linearity, with average recoveries of the two pesticides between 86% and 96% at levels of 0.02-20 mg/kg (fresh tobacco leaves) and 0.05-50 mg/kg (cured tobacco leaves), and relative standard deviations (RSDs) ranging from 3.0% to 9.4%. This method is simple, accurate, and highly feasible. Field experiments were conducted to study the decline dynamics of fluopimomide and dimethomorph in tobacco leaves, revealing that the decline dynamics of both pesticides followed the first-order kinetic model, with half-lives of 7.2-15 days and 5.3-12 days, respectively, indicating that both pesticides are readily degradable. The final residue levels 21 days after the last application were 0.045~7.2 mg/kg and 0.058~4.0 mg/kg, respectively. In this study, an HPLC-MS-MS detection method for fluopimomide and dimethomorph in tobacco leaves was established, elucidated their decline dynamics and final residues, which provided scientific evidence for their rational and safe use in tobacco cultivation and provided data support for the establishment of maximum residue limits of fluopimomide and dimethomorph in tobacco.

       

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