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    气相色谱-质谱法测定粮食种植土壤中6种农药的残留量

    Determination of 6 Pesticide Residues in Grain Planting Soil by Gas Chromatography-Mass Spectrometry

    • 摘要: 将土壤样品除杂、自然风干、粉碎过筛后,分取10.0 g置于加速溶剂萃取池中,用约10 g硅藻土和体积比1:1的乙酸乙酯-正己烷混合溶液33 mL提取。提取液经含1 g硫酸镁,500 mg N-丙基乙二胺(PSA)和500 mg C18的净化管净化后,于45℃氮吹至近干,用1.0 mL乙酸乙酯溶解,经0.22 μm滤膜过滤。滤液进入气相色谱仪,在Rtx-5MS石英毛细管色谱柱上分离后,以配有电子轰击离子源的质谱仪在多反应监测模式下检测。结果显示:粉锈宁、速保利、氟菌唑、霜霉威、萎锈灵和丙环唑的质量浓度均在0.05~5.0 mg·L-1内与其对应的峰面积呈线性关系,检出限(3S/N)分别为0.005,0.004,0.006,0.006,0.006,0.006 mg·kg-1;对空白样品进行3个浓度水平的加标回收试验,回收率为89.5%~101%;用此法对空白加标样品平行测定6次,测定值的相对标准偏差均小于5.0%。

       

      Abstract: After impurity removal, natural air drying, crushing and screening of the soil sample, 10.0 g of the soil sample was taken and placed in the accelerated solvent extraction tank, and extracted with about 10 g of diatomite and 33 mL of the mixed solution of ethyl acetate and n-hexane at a volume ratio of 1:1. The extract was purified by a purification tube containing 1 g of magnesium sulfate, 500 mg of N-propyl ethylenediamine (PSA) and 500 mg of C18, and blown to near dryness by nitrogen at 45℃. The residue was dissolved with 1.0 mL of ethyl acetate, and passed through 0.22 μm filter membrane. The filtrate was introduced into the gas chromatograph, separated on Rtx-5MS quartz capillary column, and detected in the multiple reaction monitoring mode with a mass spectrometer equipped with an electron impact ion source. As shown by the results, linear relationships between values of peak area and mass concentration of triadimefon, diniconazole, triflumizole, propamocarb, carboxin and propiconazole were found in the same range of 0.05-5.0 mg·L-1, with detection limits (3S/N) of 0.005, 0.004, 0.006, 0.006, 0.006, 0.006 mg·kg-1, respectively. Tests for recovery were made on blank samples at three concentration levels by standard addition method, giving results in the range of 89.5%-101%. The blank spiked sample was determined 6 times in parallel by this method, with RSDs of the determined values less than 5.0%.

       

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