基于磁固相萃取-便携式离子阱质谱的蔬菜中3种农药残留的快速检测

    Rapid detection of three pesticide residues in vegetables based on magnetic solid phase extraction and portable ion trap mass spectrometer

    • 摘要: 针对当前我国典型的高风险蔬菜芹菜、韭菜和豇豆中易超标农药啶虫脒、吡虫啉及禁限用农药克百威的残留问题,基于磁固相萃取和便携式离子阱质谱构建了多农药残留现场、快速检测技术。系统优化了磁固相萃取方法的关键影响因素,最佳优化条件为:2 g蔬菜样品经20 mL水萃取后,采用30 mg磁固相吸附剂,超声辅助吸附水溶液中目标农药15 min,再用4 mL体积分数为0.1%的甲酸乙腈超声解吸附3 min后进行便携式质谱分析。方法验证结果表明:啶虫脒、吡虫啉及克百威3种农药在芹菜、韭菜和豇豆样品基质溶液中的线性范围为0.01~0.25 mg/L (除吡虫啉在韭菜中的线性范围为0.05~0.5 mg/L外);检出限均为0.001~0.035 mg/L,定量限均为0.02~0.05 mg/kg;在0.02、0.05和0.2 mg/kg 3个添加水平下时,3种农药的回收率在50%~71%之间,相对标准偏差在4.2%~22%之间。该方法具有较好正确度、精密度和操作便捷等优势,在蔬菜中多种农药残留的快速定性/半定量筛查方面具有广阔的应用前景。

       

      Abstract: A rapid method was established for the detection of acetamiprid, imidacloprid and carbofuran in three typically high residue vegetables, including celery, leek and cowpea, using magnetic solid-phase extraction and portable ion trap mass spectrometer. The main extraction conditions were optimized and the suitable procedures were as follows: The vegetable samples were extracted by 20 mL water, and the target pesticides in the extracted solution was then adsorbed by 30 mg magnetic solid-phase absorbents using the ultrasonic extraction for 15 min. After the magnetic separation, the adsorbed pesticides were desorbed with 4 mL of acetonitrile with 0.1% (V/V) formic acid by ultrasonic extraction for 3 min. Method validation indicated that all the three pesticides showed good linearity in the range of 0.01-0.25 mg/L, except that it was 0.05-0.5 mg/L for imidacloprid in leek sample. The limits of detection were 0.001-0.035 mg/L, and the limits of quantitation were 0.02-0.05 mg/kg. The spiked recoveries ranged from 50% to 71% with the RSDs of 4.2% to 22% at the spiked levels of 0.02, 0.05 and 0.2 mg/kg. The presented method displayed good qualitative/semi quantitative ability, and could be used for simultaneous and rapid on-site detection of multiple pesticide residues in vegetables.

       

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