固态萃取搅拌棒技术与气相色谱联用测定植物中的有机氯农药

以固态萃取搅拌棒为样品前处理技术,采用气相色谱法分析了荞麦和苦参中的8种有机氯农药残留。实验对比了聚醚砜酮(PPESK)和聚二甲基硅氧烷(PDMS)对所测定的有机氯农药的相对萃取量(以峰面积计),发现前者是后者的1～11倍。用PPESK作萃取相,对萃取温度、萃取时间和盐浓度等萃取条件进行了优化,并考察了基质效应对萃取效率的影响。所用方法对荞麦中有机氯农药的LOD为4～85pg/g,重复性的RSD小于26%,回收率为83%～135%;对苦参中有机氯农药的LOD为3～17pg/g,重复性的RSD小于17%,回收率为82%～128%。

Determination of Organochlorine Pesticides in Plants by Stir Bar Sorptive Extraction Coupled with Gas Chromatography

Organchlorine pesticides in buckwheat and sophora flavescens were determined using stir bar sorptive extraction coupled to gas chromatography and electron capture detection.Poly(phthalazine ether sulfone ketone(PPESK) and poly(dimethysiloxane)(PDMS) were used as extraction phases,and their relative extraction amount for 8 organchlorines were compared.The results showed that the extraction capacity of PPESK were 1 to 11 times higher than that of PDMS.Factors affecting the amount of extraction,such as temperature,extraction time and ion strength,were optimized,and the matrix effect was also evaluated.Limits of detection(LOD) of organchlorines in buckwheat were between 4 pg/g and 85 pg/g;the error of precision was less than 26%;the recoveries were from 83% to 135%.The LOD of organchlorines in sophora flavescens were in the range of 3-17 pg/g,the error of precision was less than 17%,the recoveries were 82%-128%.