大青叶中3种拟除虫菊酯农药残留量的测定

目的：建立大青叶中3种拟除虫菊酯农药残留量的测定方法。方法：样品以丙酮超声提取，并采用固相萃取柱进行净化，选用气相色谱-质谱联用（GC-MS）法在DB-5MS色谱柱上采用程序升温技术分离；采用选择离子检测方式，以保留时间和特征离子进行目标成分的定性鉴别；采用外标法对样品进行测定。结果：3种拟除虫菊酯农药在10～1000μg/L范围内呈良好的线性关系，方法定量限在18．0～24．0μg／kg之间，加样回收率在80．30％-87．91％之间，相对标准偏差（RSD）〈8％（n=9）。结论：苓方法灵敏度高，重现性好，可用于大青叶中3种拟除虫菊酯农药残留的检测。

Determination of 3 Pyrethroid Pesticides in Folium Isatidis by Gas Chromatography-Mass Spectrometry

OBJECTIVE： To establish a method for determination of 3 pyrethroid pesticides in Folium lsatidis METHODS： The samples underwent ultrasonic extraction with acetone, purification by solid phase extraction column and separation by GC-MS on DB-5MS column using a temperature programming and selective ion monitoring （SIM） mode. The target components were identified qualitatively with retention time and characteristic ions as indexes. The samples were determined by external standard method. RESULTS ： The linear ranges of 3 pyrethroid pesticides were within 10-1 000 μg/ L, with methodological limits of quantification （LOQs） at 18. 0-24. 0 μg/Kg, average recovery rates of samples at 80. 30%- 87. 91% and relative standard deviations （RSD） at 〈 8% （n = 9 ）. CONCLUSION： The method is sensitive and reproducible and it can be used for the detection of residues of 3 pyrethroid pesticides in Folium Isatidis.