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目的建立一种基于微波辅助水蒸气萃取结合液液分散微萃取用于西红柿中三嗪类农药残留的绿色萃取方法。方法西红柿样品经微波辅助水蒸气萃取后,用液液微萃取法对萃取液进行净化和富集,采用液相色谱-串联质谱法(LC-MS/MS)对三嗪类农药进行定性和定量分析。结果微波辅助水蒸气萃取结合液液微萃取法的最佳萃取条件为:微波功率为200 W,萃取剂为添加300μL乙腈的水蒸气,样品与石英砂比例为1:2,收集液体积为18mL;分散液液微萃取中的萃取剂为350μL的氯仿,分散剂为600μL的丙酮,并加入0.2 g NaCl以增加三嗪类农药的回收率。在最佳的萃取条件下,6种三嗪类农药在1、50和500μg/kg添加水平的回收率为62.1%~108.1%;日内和日间精密度分别在1.6%~6.7%和4.8%~10.3%之间(n=6),方法定量限为2μg/kg。结论该方法快速、准确、灵敏,适合测定西红柿中三嗪类农药残留。
OBJECTIVE To establish a green extraction method based on microwave-assisted water vapor extraction combined with liquid-liquid dispersive microextraction for triazine pesticide residues in tomato. Methods Tomato samples were extracted by microwave-assisted water vapor, and the extracts were purified and enriched by liquid-liquid microextraction. The quality and quantity of triazine pesticides were determined by liquid chromatography-tandem mass spectrometry (LC-MS / MS) analysis. Results The optimum extraction conditions of microwave-assisted water vapor extraction combined with liquid-liquid microextraction were as follows: the microwave power was 200 W, the extractant was water vapor with 300 μL acetonitrile added, the ratio of sample to quartz sand was 1: 2, the volume of collecting liquid was 18 mL ; The extractant in the dispersion liquid microextraction was 350 μL of chloroform, the dispersant was 600 μL of acetone, and 0.2 g of NaCl was added to increase the recovery rate of the triazine pesticide. Under the optimal extraction conditions, the recoveries of six triazine pesticides at the levels of 1, 50 and 500 μg / kg were 62.1% -108.1%. The intra- and inter-day precision was 1.6% -6.7% and 4.8% ~ 10.3% (n = 6), the limit of quantification was 2μg / kg. Conclusion The method is rapid, accurate and sensitive and suitable for the determination of triazine pesticide residues in tomatoes.