材料期刊网

以自制改性多壁碳纳米管（MWNTs）和 N-丙基乙二胺（PSA）填料分层填装的双层固相萃取柱为净化柱，建立了测定陈皮及其制品中11种有机磷农药残留的分析方法。样品经乙酸乙酯提取、离心后，固相萃取柱净化，净化液经 Agilent RTS-1701毛细管柱分离，火焰光度检测器检测，外标法定量。考察了填料类型、填料用量、洗脱方式等因素对提取效率的影响。在优化条件下，11种有机磷农药检测的线性范围为0.020~1.0 mg／L，相关系数为0.9990~0.9998，检出限为3.5~9.6μg／kg。样品在10、25、100μg／kg 3种水平下的加标回收率为50.8％~109％，相对标准偏差为2.7％~8.5％。该法准确度和灵敏度高、操作简单、快速，检出限能满足对有机磷农药残留的限量要求。自制固相萃取柱可降低成本，值得推广应用。

By packing N-propylethylenediamine ( PSA ) and multi-walled carbon nanotubes (MWNTs) separately,a homemade double solid phase extraction purification column was made. A gas chromatographic method was developed for the simultaneous determination of 11 kinds of organophosphorus pesticides,including dichlorovos,methamidophos,acephate,phor-ate,omethoate,dimethoate,chlorpyrifos,malathion,parathion-ethyl,quinalphos and ethion in Xinhui dried orange peel and its products. The samples were centrifuged after extracted by ethyl acetate,and then cleaned up with a homemade double PSA/MWNTs solid phase extrac-tion column. The separation of target compounds was performed on an Agilent RTS-1701 capil-lary column with temperature programmed within 25 min,then determined by a flame photo-metric detector and quantified by using external standard method. The factors affecting the determination,such as packing type,amount of packing,elution mode,extraction solution and ultrasonic time,were investigated. Under the optimized experimental conditions,the novel method showed a good linearity in the range of 0. 020-1. 0 mg/L with correlation coefficients of 0. 999 0-0. 999 8,the limits of detection were 3. 5-9. 6 μg/kg for the pesticides. The new method was successfully applied to the analyses of organophosphorus pesticides in Xinhui dried orange peel and its products. The recoveries spiked with organophosphorus pesticides standards at three concentration levels of 10,25 and 100 μg/kg in samples were 50. 8%-109% with relative standard deviations of 2. 7%-8. 5%. The established method is accurate,sensitive,simple and fast. The detection limits of the method meet the limited requirements of organophosphorus pesticide residues. The homemade column is cost saving and worthy of popularization and application. The study provides a useful method for the analysis of trace substance.