对比3种不同的QuEChERS前处理方式在气相色谱-串联质谱检测分析烟草中上百种农药残留中的应用

Comparison of three different QuEChERS sample treatment methods in the analysis of more than one hundred pesticide residues in tobacco by gas chromatographytandem mass spectrometry

以气相色谱-串联质谱（GC-MS/MS）技术为基础,建立了适合烟草中上百种农药残留分析的3种QuEChERS前处理方法：溶剂转换法、提取液稀释法和正己烷液液萃取法.以烟草中的有机磷、有机氯、拟除虫菊酯类、酰胺类、氨基甲酸酯类、二硝基苯胺类等共155种农药为研究对象,从基质效应、共萃取基质、色谱峰干扰、回收率和定量限等方面对3种前处理方式进行对比分析.经考察发现,3种方法各有优缺点,正己烷液液萃取法得到的提取液中共萃取基质含量最少,但只能保证约100种目标物的回收率在70％ ～ 120％;溶剂转换法和提取液稀释法对绝大部分目标物都能保证回收率在70％～ 120％,适合用于多农药残留分析检测.对不同种类农药进行对比,发现有机磷、酰胺类和氨基甲酸酯类农药的基质效应相对较强,而有机氯和拟除虫菊酯类目标物的基质效应相对较弱,因此,对有机磷农药单独分析时,建议使用提取液稀释法;对有机氯和拟除虫菊酯类农药单独分析时,建议使用正己烷液液萃取法.

With a combination of QuEChERS method and gas chromatography-tandem mass spectrometry （GC-MS/MS） technique,three sample treatment methods （solvent exchange method,toluene dilution method,hexane liquid-liquid extraction method） were established to analyse more than one hundred pesticide residues in tobacco.The 155 pesticide analytes contained 58 organophosphorus,28 organochlorine,10 pyrethroids,10 acyl amide,11 carbamate,7 dinitroaniline and 31 other family pesticides.Comparison of the three treatment methods was investigated on performances including matrix effect,co-extracted matrix,peak interference,recovery and the limit of quantification （LOQ）.The hexane liquid-liquid extraction method gave the cleanest extract but poorer recovery; the solvent exchange and toluene dilution method could guarantee recoveries in the range of 70% and 120% for most of the 155 pesticides.We found that organophosphorus,acyl amide and carbamate pesticides exhibited relative strong matrix effects compared with organochlorine and pyrethroid pesticides.Toluene dilution method was recommended to analyse organophosphorus pesticides,and hexane liquid-liquid extraction （LLE） method was recommended to analyse organochlorine and pyrethroid pesticides.