气相色谱-电子轰击离子源质谱法分析卷烟和烟叶中29种农药的残留

开展了卷烟和烟叶中有机氯、有机磷和拟除虫菊酯3类29种农药残留的气相色谱-电子轰击离子源质谱(GC-EI/MS)的分析方法研究。优化与选择了卷烟和烟叶样品的前处理条件,样品经正己烷-丙酮(体积比为1∶1)混合提取剂超声提取、Florisil硅土和中性氧化铝双净化剂固相萃取柱净化、二氯甲烷-正己烷(体积比为95∶5)混合洗脱剂洗脱和浓缩后,以磷酸三苯酯(TPP)为内标物,采用GC-EI/MS的选择离子监测方式(SIM)进行定性和定量分析。当样品的加标水平为20,50,100 μg/kg时,加标回收率为70%～110%,相对标准偏差在2%～8%之间;除了甲氰菊酯、氯菊酯和溴氰菊酯的方法检出限(LOD)分别为1.85,1.74与2.54 μg/kg外,其余的26种农药的LOD均小于0.8 μg/kg;线性范围为5.0～500.0 μg/kg,相关系数都大于等于0.9994。此分析方法已成功地应用于卷烟和烟叶样品中3类29种痕量农药残留的分析

Determination of 29 pesticide residues in tobacco by gas chromatography-electron impact ionization mass spectrometry

A method was developed for rapid determination of 29 pesticide residues in tobacco based on gas chromatography coupled with electron impact ionization mass spectrometric detection (GC-EI/MS). After the optimization of different parameters, such as the extraction solvent, elution solvent, purificant, pesticides were extracted from tobacco with hexane-acetone (1∶1, v/v) in an ultrasonic bath, cleaned-up on a column, packed with Florisil and neutral alumina, eluted with dichloromethane-hexane (95∶5, v/v), and then determined by GC-EI/MS in the selected ion monitoring mode (SIM) with triphenyl phosphate (TPP) as internal standard. The recoveries were performed at 20, 50 and 100 μg/kg fortification levels for each pesticide, and the recoveries ranged from 70% to 110% with the relative standard deviations between 2% and 8%. The detection limits were less than 0.8 μg/kg for 26 pesticides except for the fenpropathrin, deltamethrin and permethrin. The method was linear over the range of 5.0-500.0 μg/kg with the correlation coefficients between 0.9994 to 0.9999. The method was successfully applied to the analysis of these pesticides in tobacco.