【作者】 谢海洋；

【导师】 何友昭；

【作者基本信息】 中国科学技术大学 ， 分析化学， 2010， 博士

【摘要】 毛细管电泳(CE)是高效、快速、样品和试剂消耗少的一种分离技术。由于CE极小的样品注入体积和极短的吸收光程,导致常用的紫外-可见吸收法的检测灵敏度差。为此,常采用高灵敏的检测器和样品预富集技术来提高毛细管电泳的检测灵敏度。本文综述了近年来液相微萃取技术和毛细管电泳在柱电动富集技术的发展和应用。本文的主要研究内容包括液相微萃取中装置的设计和制作、萃取条件的理论研究、一体化的顶空液相微萃取技术、液相微萃取技术和在柱电动富集技术联用的研究等,主要研究成果如下：1.设计并制作了液相微萃取装置,详细描述了其制作方法和要点。这些装置能完美融合顶空液相微萃取技术和毛细管电泳,以及实现液相微萃取技术和碱堆积技术结合作为双重富集方法从而显著提高CE-UV的检测灵敏度,同时也简化了样品前处理的操作步骤。2.在顶空液相微萃取理论的基础上,深入研究了在顶空液相微萃取中样品溶液体积条件对萃取富集效率的影响,经过理论推导得到最佳样品体积条件,并得到了以前多数文献结果和本论文实验结果的验证。3.建立了一体化的顶空液相微萃取和毛细管电泳直接联用的方法,并成功用于地表水中的常见酚类污染物的检测。我们研究了该技术中影响萃取效率的因素,主要有萃取接受相的选择、萃取温度、样品液pH值、搅拌速率、盐效应、样品体积、萃取时间等。在最佳萃取条件下,对六种常见的酚类的富集倍数达到520～1270。该技术对挥发性或半挥发性痕量物质,是一种富集倍数高、操作简便的毛细管区带电泳样品预富集技术。4.建立了液-液-液微萃取技术和碱堆积在柱富集技术联用的双重富集模式,并成功用于蔬菜中氨基甲酸酯类农药残留的分析。我们研究了该技术中影响富集倍数的因素,主要包括有机相的选择,萃取接受相的选择、样品体积、萃取时间、碱堆积时间等。在最佳萃取条件下,对四种常见的氨基甲酸酯类农药的富集倍数达到1100～1410。该技术是一种能有效去除样品基体干扰、富集倍数高,简便快速,操作简单的毛细管电泳在柱预富集技术。5.进一步发展了一体化顶空液相微萃取技术,使之直接与胶束电动毛细管色谱(MEKC)联用对微量非极性化合物进行检测。对药品中的酯类防腐剂(对羟基苯甲酸甲、乙和丙酯)的富集倍数达到25～86。该技术能有效浓缩样品,去除基体干扰,是一种富集倍数高、操作简便的MEKC样品预富集技术。此外,在一体化的顶空液相微萃取技术中,对于可离子化的分析物,可直接采用运行缓冲液作为萃取接受相来富集分析物。我们用此技术在稀释的酱油样品中富集测定了防腐剂山梨酸和苯甲酸的含量,并已取得重要进展。更多还原

【Abstract】 Capillary electrophoresis (CE) is a powerful separation technique with high separation efficiency, fast separation speed and low sample consumption. For its small injected sample volume and short optical path, the detection sensitivity of ultraviolet-visible (UV-Vis) spectrophotometry is not satisfied. High sensitivity detector and sample preconcentration techniques are often adopted to improve concentration detection limits in CE. The author reviews the developments and applications of liquid-phase microextraction (LPME) and on-column sample stacking in CE analysis. The main research in this thesis include design and production of liquid-phase microextraction unit, study of extraction conditions in headspace liquid-phase microextraction, the integration of headspace liquid phase microextraction with capillary electrophoresis, and the combination of liquid-liquid-liquid microextraction with base stacking as a dual preconcentration method for capillary zone electrophoresis. The details of the contents and results of the thesis are as follows:1. We design and produce two liquid-phase microextraction units and describe the method and the key point in detail. These liquid-phase microextraction units realize the integration of headspace liquid-phase microextraction with capillary electrophoresis, and the combination of liquid-liquid-liquid microextraction with base stacking as a dual preconcentration method for capillary zone electrophoresis, which highly improve the detection limits in CE and simplify the sample pretreatment steps.2. On the basis of headspace liquid-phase microextraction theory, the effect of the sample volume on the enrichment factor of HS-LPME was studied by both theoretical and experimental methods. The experimental results of our work and most of the analytes in reported work was close to our prediction.3. An analytical technique of in-line coupling headspace liquid-phase microextraction (HS-LPME) with capillary electrophoresis (CE) was proposed to determine volatile analytes. To evaluate the proposed method, phenols were used as model analytes. The parameters affecting the extraction efficiency were investigated, including the configuration of acceptor phase, kind and concentration of acceptor solution, extraction temperature and time, salt-out effect, sample volume, etc. Under the selected conditions, the enrichment factors were obtained from 520 to 1270. The proposed method was successfully applied to the quantitative analysis of the phenols in tap water, and proved to be a simple, convenient and reliable sample preconcentration and determination method for volatile analytes in water samples.4. A simple and efficient dual preconcentration method of on-column liquid-liquid-liquid microextraction (LLLME) coupled with base stacking was developed for capillary zone electrophoresis (CZE) in this paper. Four N-methyl carbamates were used as target compounds to evaluate the enrichment means. The parameters affecting the extraction efficiency were investigated, including the selection of organic phase, kind and concentration of acceptor solution, extraction time, sample volume and the injection time in base stacking etc. Under the selected conditions, the enrichment factors of the carbamates were obtained from 1100 to 1410. The analytical results demonstrated that the LLLME coupled with base stacking was a simple, convenient and reliable on-column sample pretreatment method for the analysis of anionic analytes in CZE.5. We developed in-line headspace liquid phase microextraction technique, and realized the direct preconcentration the non-polar compounds in micellar electrokinetic capillary chromatography (MEKC). The method was applied to the analysis of p-hydroxybenzoate preservatives in medicine. The enrichment factors of methyl-, ethyl-and propyl-parabens ranged from 25 to 86. The integrative coupling technique was able to concentrate analytes and eliminate the matrix interference effectively, and be used to determine neutral analytes in complex samples by CE. The running buffer could be adopted as acceptor phase in the analysis of ionized compouds in the intergrative headspace liquid phase microextraction technique. More recently, benzoic acid and sorbic acid preservatives in diluted soy sauce samples were analyzed by the this method, and we have made some important progress.更多还原