大体积进样-气相色谱-质谱法测定白芍中15种农药残留

目的:建立同时测定白芍中有机氯、有机磷和拟除虫菊酯类等15种农药残留的大体积进样-气相色谱-质谱联用(LVI-GC-MS)分析方法。方法:采用大体积进样-气相色谱-质谱法,色谱柱为DB-5MS毛细管柱(30 m×250μm,0.25μm),程序升温:初始温度40℃保持1 min,然后以20℃/min升至210℃保持2 min,以5℃/min升至280℃保持22 min。进样量15μl,流速1.0 ml/min。结果:各农药在一定质量浓度范围内线性关系良好,相关系数r=0.9937～0.9995。在10μg/kg和100μg/kg两个质量浓度水平下,各农药的回收率为60.4%～106.8%(除二甲戊乐灵和4,4’-DDE为53.1%、45.2%外),相对标准偏差(RSD)为3.6%～18.6%,检测限(S/N=3)为0.16～3.59μg/kg。样品中检测到4,4’-DDE,其含量远低于药典规定的残留限量。结论:本研究建立的LVI-GC-MS方法操作简单、准确、灵敏度高、成本低,可以实现白芍药材中多农药残留的快速检测。

Determination of fifteen pesticide residues in Radix Paeoniae Alba by gas chromatography-mass spectrometry with large volume injection

Objective: To establish a method for the simultaneous determination of 15 pesticides residues in Radix Paeoniae Alba by large volume injection-gas chromatography-mass spectrometry(LVI-GC-MS). Methods: The pesticides,including organochlorine pesticides,organophoshporus pesticides and pyrethroid insecticides,were analyzed by LVI-GC-MS using DB-5MS capillary column(30 m × 250 μm,0.25 μm).The column temperature programming:initial temperature 40℃ for 1 min,with the increasing rate of 20℃/min to 210℃ for 2 min,then with the increasing rate of 5℃/min to 280℃ for 22 min.The flow of carrier gas was 1.0 ml/min with the injection volume of 15 μl. Results: The calibration curves of the pesticides were linear in the specified concentration ranges with correlation coefficients of 0.9937-0.9995.The average recoveries of the pesticides in Radix Paeoniae Alba spiked at two spiked levels ranged from 60.4% to 106.8%(for pendimethalin and 4,4′-DDE those were 53.1% and 45.2%) with relative standard deviation(RSD) of 3.6% to 18.6%,and the detection limits(S/N=3) were in the range of 0.16 μg/kg to 3.59 μg/kg. Conclusion: The established method for determination of multi-pesticide residue in Radix Paeoniae Alba is rapid,convenient and accurate with high sensitivity and low-cost.