白芍中19种农药残留的毛细管电泳-质谱联用检测方法

摘要

Objective:To establish a capillary electrophoresis-mass spectrometry( CE-MS) method for the analysis of nineteen organonitrogen pesticides in Paeoniae Radix Alba. Methods:CE-MS analysis was performed on a 70 cm ×50 |xm fused-silica capillary. The optimal buffer was composed of 1% formic acid and 15% methanol ( V/V, pH 2. 2). The temperature of capillary was controlled at 25t. The separation voltage was + 20 kV. The optimal MS parameters were as follows; ESI-MS analysis was performed in the positive mode;90% methanol containing 0. 2% formic acid with a flow rate of 8 μl · min was selected as the sheath liquid; the flow rate and temperature of drying gas were 6 L · min and 250t , respectively; The nebulizing gas pressure was set at 5 psig;The optimal values of fragmentor and ESI voltage were 100 V and 5 000 V,respectively. Results: The nineteen pesticides had good linearityover the testing ranges. The average recoveries were in the range of 80. 1 % - 108. 4% with RSDs less than 20% (except ethoxyquin and spiroxamine, those of which were 29. 2% and 22. 3% at 0. 01 mg · kg-1 concentration level). The LODs of nineteen pesticides were 0. 503 ~ 10. 1 μg · kg-1 . Conclusion; The method can be used effectively to analyze the nineteen organonitrogen pesticides residue in Paeoniae Radix Alba.%目的:建立白芍药材中19种有机氮类农药残留的毛细管电泳-质谱联用(CE-MS)检测方法.方法:采用CE-MS方法,熔融石英毛细管柱(70 cm×50 μm),运行缓冲液为1％甲酸-15％甲醇水溶液(V/V,pH 2.2).毛细管温度为25℃,分离电压为20 kV.质谱条件:采用电喷雾离子源(ESI),正离子模式检测；鞘液为90％甲醇-0.2％甲酸水溶液,流速为8μl·min-1；干燥气流速为6 L· min-1,干燥气温度为250℃；雾化气压力为5 psig;碎片电压为100 V,毛细管电压为5 000 V.结果:19种农药在一定浓度范围内呈线性关系,相关系数为0.9918 ～0.9986.19种农药的加样回收率为80.1％～108.4％,相对标准偏差(RSD)＜20％(除螺环菌胺为22.3％,乙氧喹啉为29.2％外),检测限(LOD)为0.503μg·kg-1～10.1 μg· kg-1.结论:该CE-MS分析方法专属性强、重现性好,适用于白芍药材中有机氮类农药的检测分析.