HS-SPME-GC-QTOF测定稻米中二硫代氨基甲酸酯类农药残留

    Determination of dithiocarbamate pesticide residues in rice using HS-SPME-GC-QTOF

    • 摘要: 本研究开发了一种水稻中二硫代氨基甲酸酯类农药残留检测的顶空-固相微萃取技术与气相色谱飞行时间质谱联用(HS-SPME-GC-QTOF)的方法。二硫代氨基甲酸酯类农药与氯化亚锡-盐酸溶液在顶空瓶中通过水浴锅加热到80 ℃发生酸热水解反应,生成衍生化产物二硫化碳(CS2),通过固相微萃取技术(SPME)萃取顶空瓶中CS2,并使用气相色谱飞行时间质谱进行检测。结果表明:SPME的最佳萃取涂层为聚二乙烯基苯/羧基/聚二甲基硅氧烷 (DVB/CAR/PDMS)、萃取温度为40 ℃、萃取时间为10 min;CS2在0.005~2 mg/L范围内线性良好(R2 = 0.9967);二硫代氨基甲酸酯类农药在稻米基质中的平均回收率为70%~116%,标准偏差为1.9%~7.6%,检出限为0.005 mg/kg、定量限为0.05 mg/kg。相比较于其他方法,HS-SPME-GC-QTOF可自动化、准确度高、环境友好,在实际样品检测中具有广阔的应用前景

       

      Abstract: A new method was developed for the determination of dithiocarbamate pesticide residues in rice by combining headspace-solid phase microextraction with gas chromatography time-of-flight mass spectrometry (HS-SPME-GC-QTOF). Based on the derivatization principle, dithiocarbamate pesticides react with stannous chloride-hydrochloric acid solution to produce carbon disulfide (CS2) derivatives via water-bath heating at 80 ℃ in headspace vials. Then the generated CS2 was absorbed by SPME fiber and analyzed by GC-QTOF. The results indicated that the optimal SPME conditions were DVB/CAR/PDMS fiber, extraction temperature of 40 ℃ and extraction time of 10 min. Good linearity of CS2 was achieved within the concentration range of 0.005~2 mg/L (R2 = 0.9967). The average spiked recoveries of dithiocarbamate pesticides in rice substrates were in the range of 70%-116%, and RSDs were 1.9%-7.6%. The limit of detection (LOD) and limit of quantification (LOQ) were 0.005 mg/kg and 0.05 mg/kg, respectively. Compared with conventional detection methods, this established HS-SPME-GC-QTOF method possesses the advantages of easy automation, high precision and favorable greenness, which exhibits great application potential in routine residue analysis of rice samples.

       

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