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在系统优化固相萃取吸附剂填料类型和洗脱溶剂种类的基础上,建立了含硫蔬菜(青葱、韭菜和蒜薹)中86种农药残留的气相色谱-负化学离子源质谱(GC-NCI/MS)的测定方法。样品在低温冷冻的条件下,加磷酸去除大部分硫化物,然后用乙腈均质提取,经装有无水碳酸钠的石墨化碳黑/氨基固相萃取柱(ENVI-Carb/NH_2)净化后,用GC-NCI/MS选择离子监测方式(SIM)进行检测,外标法定量。结果表明,86种农药在相应的范围内线性关系良好,相关系数均大于0.99,方法检出限(以3倍信噪比计)为0.05~3.33μg/kg,方法定量限(以10倍信噪比计)为0.16~9.99μg/kg,在10,50和100μg/kg的加标水平下,各目标农药的平均添加回收率为70.3%~117.5%,相对标准偏差(RSD)为4.5%~18.7%。该方法灵敏、准确,相比其他含硫蔬菜分析方法净化效果好,可用于含硫蔬菜中86种农药残留的检测。
Gas chromatography-negative chemical ionization mass spectrometry (GC-NCI / GC-MS / MS) was developed for the determination of 86 pesticide residues in sulfur-containing vegetables (green onions, leeks and garlic sprouts) based on the optimization of packing types and solvent- MS). Samples were chilled to remove phosphorous acid to remove most of the sulfide and then homogenized with acetonitrile. After purification by ENVI-Carb / NH 2 column with anhydrous sodium carbonate , Using GC-NCI / MS selected ion monitoring mode (SIM) for detection, external standard quantitative. The results showed that 86 pesticides showed a good linear relationship in the corresponding range with the correlation coefficients greater than 0.99. The detection limit (by 3 times signal-to-noise ratio) was 0.05-3.33 μg / kg, and the limit of quantification The average recovery of each target pesticide was 70.3% ~ 117.5% and the relative standard deviation (RSD) was 4.5% at the spiked level of 10, 50 and 100 μg / kg, ~ 18.7%. The method is sensitive and accurate and has a good purification effect compared with other sulfur-containing vegetable analysis methods and can be used for the detection of 86 pesticide residues in sulfur-containing vegetables.