基质分散固相萃取-超高效液相色谱-串联质谱法测定蔬菜风险监测中的9种农药残留

建立了基质分散固相萃取-超高效液相色谱-串联质谱测定蔬菜中多菌灵、氧乐果、克百威、涕灭威、毒死蜱、甲胺磷、甲拌磷、对硫磷、甲基对硫磷9种农药残留的方法。蔬菜通过乙腈提取、盐析分配、基质分散固相萃取净化后,采用Waters BEH C18柱(100 mm×2.1 mm, 1.7 μm),以乙腈和0.1%甲酸水溶液作为流动相,梯度洗脱,电喷雾电离正离子(ESI⁺)、多反应监测(MRM)模式测定,基质匹配标准溶液工作曲线法定量。该方法的检出限为0.8~4.0 μg/kg,回收率为72.8%~117.4%。50批蔬菜样品中毒死蜱、多菌灵和氧乐果残留的检出率分别为42.0%、14.0%和2.0%,毒死蜱超标率为8.0%,其他农药未检出。该法可同时测定食品风险监测中蔬菜的农药残留,具有操作方便、准确率高、重复性好等优点,可满足蔬菜中农药残留的检测要求。

Determination of nine pesticide residues in vegetables by matrix solid-phase dispersion-ultra performance liquid chromatography-tandem mass spectrometry

A matrix solid-phase dispersion-ultra performance liquid chromatography-tandem mass spectrometry (MSPD-UPLC-MS/MS) method was established for the simultaneous determination of carbendiazin, omethoate, carbofuran, aldicarb, chlorpyrifos, methamidophos, phorate, parathion and parathion-methyl residues in vegetables. The samples were extracted by acetonitrile and separated with salting out method. And then the supernatants were purified by matrix solid-phase dispersion for the UPLC-MS/MS analysis. The separation was performed on a Waters Acquity UPLC system with a BEH C18 column with the gradient elution of acetonitrile and water containing 0.1%(v/v) acetic acid. The nine pesticides were determined in the modes of electrospray positive ionization (ESI⁺) and multiple reaction monitoring (MRM). The analytes were quantified by matrix matched standard solution curves. The limits of detection (S/N≥3) were 0.8-4.0 μg/kg. The average recoveries were 72.8%-117.4%. The detection rates were 42.0% for chlorpyrifos, 14.0% for carbendiazin and 1.5% for dimethoate, and the excessive rate of chlorpyrifos was 8.0% in the determination of 50 real samples; the other pesticides were not detected. The method is simple, accurate and highly reproducible. This method is suitable for the quality control of pesticide residues in risk monitoring of the safety of the foods.