QuEChERS结合气相色谱-质谱法测定农产品中杀螨剂和拟除虫菊酯农药残留

建立了QuEChERS-改性多壁碳纳米管提取净化,气相色谱-质谱法同时检测农产品中1种杀螨剂和8种拟除虫菊酯农药的分析方法。样品经水浸润后,以乙酸乙酯-正己烷混合溶剂提取,再以适量改性多壁碳纳米管填料净化提取液,净化液以Shimadzu Rtx-1701毛细管色谱柱为分离柱,采用质谱测定和确证,选择离子模式监测,外标法定量。在优化实验条件下,9种农药在0.010~1.0μg/mL范围内具有良好的线性关系,相关系数为0.9840~0.9977,检出限(S/N=3)为2.2~6.2μg/kg。3个加标水平下的平均回收率为76.7%~107%,相对标准偏差为3.1%~9.5%。该方法准确、灵敏度高、操作简单、快速,可满足新会陈皮等农产品中上述9种农药残留同时测定的要求。

Determination of Acaricide and Pyrethroid Pesticides Residues in Farm Produce by QuEChERS and Gas Chromatography-Mass Spectrometry

An analytical method based on QuEChERS with modified multiwalled carbon nanotubes (MWNTs) as adsorbent was developed.The determination of 1 acaricide and 8 pyrethroid pesticide residues in xinhui dried orange peel and other agricultural products was carried out by gas chromatography-mass spectrometry(GC-MS).The factors affecting the extraction,purification,detection efficiency were optimized.The separation was performed on a Shimadzu Rtx-1701 capillary column with temperature programmed within 46 min,and their contents were confirmed and determined by GC-MS under selected ion monitoring mode by using external standard.Under the optimized conditions,the calibration curves of 9 pesticides were linear in the range of 0.010-1.0 μg/mL with correlation coefficients of 0.9840-0.9977.The detection limits were in the range of 2.2-6.2 μg/kg(S/N=3).The recoveries of the pesticides in xinhui dried orange peel and its products at three spiked levels ranged from 76.7％ 107％,with relative standard deviations of 3.1％-9.5％.With the advantages of accurate,sensitive and rapid detection and easy operation,the method is applicable in the simultaneous determination of 9 kinds of pesticides in xinhui dried orange peel and other agricultural products.The study provides a useful method for the analysis of trace substance and the proposed method can be applied to the dctermination of 9 pesticide residues in real products with satisfactory results.