多壁纳米碳管固相萃取测定水中的有机氯农药

对于水样中的有机氯农药的净化方法主要是采用传统的液液分配的方法,缺点是溶剂使用量和前处理复杂。近年来固相萃取及固相微萃取等技术被应用到水样中的有机污染物的测定。如利用键合在硅胶上的非极性(C18,LC18等)或极性物质(LC-CN,LC-NH2)对水中有机物进行富集,用GDX或XAD自填的固相柱的报道也很多。纳米技术和纳米材料的发展为开发固相萃取材料带来新契机。纳米材料是指尺寸大小在从1～100m之间物质。与普通的块体材料相比,纳米材料具有较大的比表面,因而有可能具有较大吸附容量。纳米材料在环境有机污染物分离富集方面的应用研究才刚刚开始。本文主要就纳米碳管对水样中的有机氯农药进行研究,优化固相萃取条件。

Multiwalled Carbon Nanotubes as a Solid-Phase Extraction Adsorbent for the Determination of OCPs in Water

The adsorptive potential of multiwalled carbon nanotubes (MWNTs) for solid-phase extraction of HCHs and DDT in water was investigated for the first time. The analytes are quantitatively adsorbed on a MWNTs-packed cartridge, then the analytes retained on the cartridge are quantitatively desorbed with suitable amounts of acetone and ethyl acetate. Finally, the analytes in the eluent are determined by gas chrornatography. Parameters influencing the extraction efficiency, such as volume of the sample solutions, pH of the sample, methanol content in water, solid-phase extraction adsorbent amount and the eluent solution and eluent volume were examined. Comparative studies showed that MWNTs were at least as effective as C18 for the extraction of OCPS in water. When the extraction volume was less than 500 mL there was no OCPs detected for saturation OCPs solution. The accuracy of the proposed method was tested by recovery measurements on spiked samples, and good recovery results( 68.9% - 102.9% ) were obtained compared with liquid-liquid extraction method. And the relative standard deviation was from 3.81% to 15.05% (the sample number is 3). The detection limit of this method is range from 0.02 to 10.60 ng/mL for different organoclorine pesticides.