超高效液相色谱-串联质谱法测定牛乳中氯虫苯甲酰胺、氟苯虫酰胺和2甲4氯的残留

目的:建立了一种牛乳中氯虫苯甲酰胺、氟苯虫酰胺和2甲4氯的超高效液相色谱-串联质谱（UPLC-MS/MS）检测方法。方法:样品经乙腈提取，氯化钠盐析，正己烷除脂，两步低温冷冻离心净化；采用Acquity UPLC BEH C₁₈柱（50 mm×2.1 mm（i.d.），1.7 μm）色谱柱分离，以乙腈和0.1%甲酸水溶液为流动相进行梯度洗脱；采用电喷雾电离源，正负离子切换模式扫描，多反应监测模式，以基质标准曲线外标法进行定量。结果:三种农药在10~150 ng/mL范围内线性关系良好（R2>0.999）。分别在5.0、10.0和50.0 μg/kg添加水平进行添加回收实验，三种农药的平均回收率在73.3%~117.3%之间，相对标准偏差在1.0%~5.9%之间（n=6）；方法的检出限（S/N≥3）和定量限（S/N≥10）分别为1.0、5.0 μg/kg。结论:本方法简便、准确、灵敏，适用于牛乳中氯虫苯甲酰胺、氟苯虫酰胺和2甲4氯的同时测定。

Determination of Chlorantraniliprole,Flubendiamide and 2-Methyl-4-chlorophenoxyacetic Acid Residues in Milk by Ultra Performance Liquid Chromatography-tandem Mass Spectrometry

Objective: A method was developed for the determination of chlorantraniliprole, flubendiamide and 2-methyl-4-chlorophenoxyacetic acid in milk by ultra performance liquid chromatography-tandemmass spectrometry (UPLC-MS/MS). Methods: The samples were extracted by acetonitrile, salted out by sodium chloride, degreased by n-hexane and purified by two-step cryogenic centrifugation. The analytes were separated by Waters Acquity UPLC BEH C₁₈ chromatographic column. The mobile phase was eluted with a gradient of acetonitrile and 0.1% formic acid aqueous solution. The detection was carried out with electrospray ion source, positive and negative ion switching, scanning mode and the quantification was accomplished by external standard method of matrix standard curve. Results: The three pesticides showed a good linear relationship (R2>0.999) in the range of 10~150 ng/mL. With the addition of 5.0, 10.0 and 50.0 μg/kg in the standard recovery experiment, the recoveries were 73.3%~117.3% and the relative standard deviations were 1.0%~5.9% (n=6). The detection limits (S/N≥3) and the limit of quantification of the method (S/N≥10) were 1.0 and 5.0 μg/kg, respectively. Conclusion: This method is simple, accurate and sensitive, which is suitable for simultaneous determination of chlorfenoxamide, fluorofenoxamide and 2-methyl-4-chlorophenoxyacetic acid residues in milk.