QuEChERS-气相色谱-质谱法同时测定小麦胚中45种农药残留

Simultaneous determination of 45 kinds of pesticide residues in wheat germ by QuEChERS-gas chromatography-mass spectrometry

目的建立QuEChERS-气相色谱-质谱法(gas chromatography-mass spectrometry,GC-MS)同时测定小麦胚中45种农药残留的方法。方法通过比较目标化合物特征定量离子的响应值,选取适宜的复溶溶剂,并通过比较标准曲线的斜率,明确所有待测目标化合物的基质效应。采用含有1%醋酸的乙腈作为溶剂提取样品中的目标农药,经QuEChERS技术净化和溶剂复溶置换后,使用气相色谱-质谱法在选择离子监测(selected ion monitoring,SIM)模式下测定,通过空白基质匹配标准溶液内标法定量。结果乙酸乙酯是较为理想的复溶溶剂,所有待测目标物均表现出不同程度的基质增强效应。45种目标农药在0.005~0.500μg/mL的质量浓度范围内呈现出较好的线性关系,相关系数均大于0.9991;定量限在0.0030~0.0075 mg/kg之间。3个水平的加标回收率均在81.54%~111.62%范围内,相对标准偏差(relative standard deviations,RSDs)在0.34%~9.84%范围内(n=5)。结论该方法前处理过程简单,灵敏度好、准确性高、重复性好,适用于小麦胚片及以其为主要原料的食品中多农药残留的快速筛查和定量检测。

Objective To establish a method for the simultaneous determination of 45 kinds of pesticide residues in wheat germ by QuEChERS-gas chromatography-mass spectrometry(GC-MS).Methods By comparing the response values of characteristic quantitative ions of target compounds,the appropriatere-soluble solvent was selected,and the matrix effects of all target compounds were determined by comparing the slopes of the standard curves.After extracted with acetonitrile containing 1%acetic acid,purified by the QuEChERS method,redissolved and replaced,45 kinds of target pesticides were determined by GC-MS under selected ion monitoring(SIM)mode,and quantified by blank matrix matching standard solution with internal standard method.Results Acetyl acetate was appropriate re-dissolved solvent,all of the target pesticides showed different degree of positive matrix effects.The 45 kinds of pesticides in the concentration range of 0.005‒0.500μg/mL showed good linear relationships,and the correlation coefficients were all greater than 0.9991.The limits of quantitation were 0.0030‒0.0075 mg/kg.The recoveries of spiked samples at 3 levels ranged from 81.54%to 111.62%,with the relative standard deviations(RSDs)in the range of 0.34%‒9.84%(n=5).Conclusion The method has the advantages of simple pretreatment process,high sensitivity,high accuracy and easy repetition,which is suitable for the rapid screening and quantitative determination of multiple pesticide residues in wheat germ and food with wheat germ as main raw materials.