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    气相色谱-质谱法结合QuEChERS方法和分散液液微萃取技术测定茭白中三唑类农药残留

    Determination of Triazole Pesticides in Zizania Latifolia by GC-MS Combined with QuEChERS and Dispersive Liquid-Liquid Microextraction

    • 摘要: 采用QuEChERS方法结合分散液液微萃取技术萃取茭白中的腈菌唑、戊唑醇和苯醚甲环唑残留,并采用气相色谱-质谱法进行测定。3.000 g样品经3 mL乙腈超声提取1 min,提取液经30 mg的PSA与30 mg的C18混合吸附剂净化。移取800 μL净化液于巴斯德吸管中,加入甲苯30 μL,混匀后快速注入水2.5 mL,超声45 s后离心,上层有机相经无水硫酸钠除水后在DB-5MS毛细管色谱柱上分离,质谱分析中选择电子轰击离子源和选择离子监测模式。3种农药的线性范围分别为5.0~500,5.0~500,12.5~1 250 μg·kg-1,检出限(3S/N)分别为1.4,0.86,3.0 μg·kg-1。加标回收率为82.7%~116%,测定值的相对标准偏差(n=5)为4.1%~15%。

       

      Abstract: The residues of myclobutanil, tebuconazole and difenoconazole in Zizania latifolia were extracted with a method of QuEChERS combined with dispersive liquid-liquid microextraction (DLLME), and then determined by GC-MS. The sample (3.000 g) was ultrasonically extracted with 3 mL of acetonitrile for 1 min, and the extract was cleaned up with a mixture of PSA (30 mg) and C18 (30 mg). The purified solution (800 μL) was transferred to Pasteur pipette, and then 30 μL of toluene was added. After the solution was mixed well, 2.5 mL of water was injected quickly and the solution was treated with ultrasonic for 45 s and centrifugation. After dehydration with anhydrous sodium sulfate, the upper organic phase was separated on a DB-5MS capillary chromatographic column. EI and SIM were adopted in MS analysis. The linearity ranges of the 3 presticides were 5.0-500, 5.0-500, 12.5-1 250 μg·kg-1 respectively, with detection limits of 1.4, 0.86, 3.0 μg·kg-1 respectively. Recovery rates obtained by standard addition method were 82.7%-116%, and RSDs (n=5) were 4.1%-15%.

       

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