蔬菜农药残留GC-MS分析方法改进与基质效应探讨

改进了国家标准GB/T5009.20-2003和农业部标准NY/T761-2004中的2种样品前处理方法,适用于GC-MS多农药残留检测,并探讨了基质效应的影响。使用GC-MS-SIM检测,做到了快速准确地检测多种农药残留、排除假阳性;采用基质标准结合单点校正进行定量分析,解决了保留时间的漂移,基质增强效应和个别有机磷农药拖尾的问题。建议使用农业部标准的改进方法进行多种农药的检测,而在甲胺磷或乙酰甲胺磷的单项检测中使用国标改进方法。采用2次脱水的国标改进方法,加标回收率在70%~105%;采用丙酮 正己烷混合溶剂溶样的农业部标准改进方法,加标回收率在90%~105%(甲胺磷和乙酰甲胺磷在65%左右),2种方法的相对标准偏差均在15%以内。

An Improvement on the GC-MS Method for Vegetable Pesticide Residues Analysis and Discussion of Matrix Effects

This paper improves two sample pretreatment methods stipulated in GB/TS009.20-2003 and NY/ T761-2004. These improved methods can be used in many kinds of vegetable pesticides residues analysis and also discuss the matrix effect. GC-MS-SIM can analyze vegetable pesticide residues rapidly, accurately and elimihate false positives. Using extraction standard with a unitary criterion for quantitative analysis, it can avoid the matrix effects, such as the change in the retention time and the matrix enhance effect, and solve the problem of tailed peaks for some organophorus pesticides. The improved method of NY/T761-2004 can be used in the determination of multiresidue pesticides in vegetables, and the improved method of GB/TS009.20-2003 can be used in the determination of Methamidophos or Acephate. The dehydration process in the improved method of GB/T5009.20-2003 uses double dehydration to dehydrate the extraction, and the recoveries are 70 % -105 %. Dissolving the extraction with a mixture of Acetone and Hexane in the improved method of NY/T761-2004, the recoveries are 90 % - 105 % except Methamidophos and Acephate, which are about 65 %. The relative standard deviations of the two improved methods are less than 15 %.