多壁碳纳米管固相萃取净化气相色谱法分析蔬菜中有机氯和拟除虫菊酯农药残留

Analysis of organochlorine pesticides and pyrethroid pesticides in vegetables by gas chromatography-electron capture detection coupled with solid-phase extraction using multiwalled carbon nanotubes as adsorbent

建立了多壁碳纳米管为吸附剂的固相萃取(SPE)净化、气相色谱-电子捕获检测(GC-ECD)测定蔬菜中6种有机氯和7种拟除虫菊酯农药的方法。采用双柱(HP-50和HP-1色谱柱)双检测器进行定性和定量分析。蔬菜样品采用乙腈提取,多壁碳纳米管SPE柱净化,正己烷溶解上样,丙酮-正己烷(7∶3,v/v)洗脱,13种农药中有11种农药的添加回收率高于70%。将该净化方法用于荷兰黄瓜、卷心菜、红圣女果、奶油生菜、紫甘蓝、韭菜、大葱和洋葱等样品的净化,与弗罗里硅土SPE柱相比较,净化效果更好,表明多壁碳纳米管具有较强的吸附去除色素的能力,可以避免色素对测定的干扰。

A multi-residue analytical method based on solid-phase extraction（SPE） with multi-walled carbon nanotubes（MWCNTs） as adsorbent was developed.The determination of 6 organochlorine pesticides and 7 pyrethroid pesticides in vegetables（including cucumber,cherry tomato,cabbage,lettuce,purple cabbage,leek,shallot and onion） was carried out by gas chromatography-electron capture detection（GC-ECD）.The GC-ECD method used two columns（HP-50 and HP-1） and two ECD detectors.The HP-50 column was used for the analysis and the HP-1 column for validation.The clean-up conditions were optimized.The analytes were extracted by acetonitrile,and the extract was cleaned up by the MWCNTs SPE cartridge.The extract was re-dissolved by hexane,eluted with acetone-hexane（7∶3,v/v） from the columns.The recoveries were over 70% for the 11 pesticides in the 13 pesticides.The results indicated that the MWCNTs SPE cartridge was efficient for 8 vegetable samples,because it reduced the contamination of the coloring materials to GC-ECD.The experimental results showed the MWCNTs SPE cartridge can adsorb the coloring materials and the eluant was nearly colorless.