GC-MS法测定拟除虫菊酯类农药残留

RAPID GC-MS DETERMINATION OF RESIDUAL PYRETHROID PESTICIDES IN VEGETABLES AND FRUITS

介绍了蔬菜水果中8种拟除虫菊酯农药残留的快速检测方法。采用选择离子一气相色译质谱联用（SIM—GC-MS）方式，依据保留时间和特征离子丰度比对农药进行确证。此方法可以在13．50min内快速检测拟除虫菊酯农药残留，并可同时定性和定量，用于蔬菜水果等多种作物的检验。回收率在75％-108％间，相对标准偏差〈10%，检出限为0．00090～0．0084mg·kg^-1。

The sample solution of vegetable or fruit was prepared by treating the sample （20 g） through the following steps： disintegration of sample; extraction with methyl cyanide; evaporation of an aliquot of the methyl cyanide extract on a water bath at 80℃ to nearly dryness; taking up the solution with n-hexane and passing the solution through florisil column; evaporation of the eluate, on a water bath at 55 ℃ with blowing of nitrogen, to nearly dryness; diluting of the solution to 2. 0 mL with n-hexane; filtration with 0. 45 μm filtermenbrane and sampling for GC-MS determination. The selected ion mode and the mass selective detector were applied in the GCMS analysis, eliminating effectively the matrix interferences. The residual pesticides were characterized, both qualitatively and quantitatively, according to the retention time and the abundance of characteristic ion. Recoveries were found to be in the range of 75%--108%. RSD＇s were less than 10%. Limit of detections were in the range of 0. 000 90-0. 008 4 mg · kg^-1.