论文标题:新型固相微萃取探头的制备、研究与应用
Preparation, Study and Application of New Solid-Phase Miroextraction Fibers
论文作者 赵鸿雁
论文导师 陆光汉,论文学位 硕士,论文专业 分析化学
论文单位 华中师范大学,点击次数 73,论文页数 60页File Size2612k
2003-05-01论文网 http://www.lw23.com/lunwen_903918857/ 固相微萃取,Nafion,聚吡咯,活性炭,碳纤维
Solid-Phase Microextraction,Nafion,Polypyrrole,active carbon,carbon fiber
近年来，随着人们环保意识的增强，出现了一些新兴的无溶剂和少溶剂的样品前处理技术，固相微萃取技术就是新发展的一种无溶剂萃取技术，它集采样、萃取、富集、进样于一体，具有简单、高效、无污染、易与其它仪器联用等优点。固相微萃取技术从出现至今，主要在萃取方式、萃取理论、联用技术、涂层材料、涂渍技术等方面有了很大的发展。但SPME还有很多有待发展的地方。由于SPME探头涂层是整个技术的核心，它决定了检测的灵敏度和选择性等，所以开发不同性质的涂层是拓宽SPME技术的研究重点。 大多数情况下，商用探头可以成功的分析非极性和中等极性的物质，而极性物质如酚类物质、脂肪酸等则需要转化为非极性衍生物才能测定，根据相似相溶的原理，寻找极性稳定的涂层材料就成了研究的关键。并且商业探头寿命一般偏短(30—50次)，容易损坏，且价格偏高。因此开发经济有效、选择性强、灵敏度高、稳定性好、寿命长的涂层材料为本文的研究目的。本文即从这些方面开发了两类新型SPME涂层材料，并依据这两种新材料制备了3种SPME探头。 Nafion是广泛用于电化学和制碱工业上的一种性能优良的材料。它是一种全氟磺酸型离子交换剂，溶液可通过蒸发成膜。具有很高的热稳定性和化学稳定性，国外曾有人尝试了它在SPME中的应用，并未深入研究，本文开发了以Nafion为涂层材料的SPME探头，制备了Nafion探头和Nafion/AC (Nafion和活性炭)探头，并分别对这两种探头优化了萃取醇类和乙酸乙酯的实验条件，包括它们的萃取时间、萃取温度、解吸时间、解吸温度、搅拌条件和盐析的测试。并与商业涂层进行了萃取能力的对照。还考察了其测定醇类和乙酸乙酯的线性范围、检测限。两种探头都具有较低的检测限，较宽的线性范围，使用寿命长，与商用探头相比，对极性物质有明显好的萃取效率，并且测定了样品中甲醇和乙酸乙酯的含量，取得了较好的效果。 吡咯是一种新型的聚合电解质，具有高稳定性、吸附性强、易于制得、衍生物多样等特性，广泛用作离子交换剂、能量储存材料、防腐涂层、催化剂、化学传感器、分离材料等，由于它的多功能和优良特性，可以引入到SPME中用作制备SPME探头材料，国外也有人作了初步的开发，证明它不仅可以用来萃取挥发性、半挥发性物质还可以萃取溶液中的离子。本文最后一章探索了在不同条件下制得聚吡咯SPME涂层探头的方法，并且引入了碳纤维作为聚合吡咯的基体材料，制备了对极性物质具有强吸附性的聚吡咯包裹的碳纤维—聚吡咯/碳纤维(Ppy/CF)固相微萃取探头，实验中优化了测定醇类的实验条件，并用模拟样品测定了其回收率，证明Ppy/CFSPME探头具有很大的开发前景。
Solid-Phase Microextraction(SPME), a novel solvent-free method, integrates extraction, concentration and sample introduction in one step; it"s not only much quicker and simpler than conventional methods, but also sensitive, portable, and easily combined with other instruments, such as gas chromatography, high-performance liquid chromatography, capillary electrophoresis etc. Till now, this technique has mainly been developed in extraction modes, extraction theory, coupled equipment, coating material and coating technology. But there is still much more work needed to do. Since in real application, the material of SPME coating determines the detection sensitivity and selectivity. The development of material of Solid-Phase Microextraction coating is the important aspect in SPME. Therefore making more novel solid phase coatings can enable the SPME more adaptable in more fields.In most cases, commercial SPME fiber can successfully analyze the compounds with non-polarity or medium polarity, but for polar compounds, it can only deal with their derivative countparts. According to such a theorem "It"s easier for analogical substances to dissolve each other", the key part consists in searching the steady and polar coating material. What"s more, commercial SPME fiber is fragile, too expensive, and short-life. These shortcomings limit the range of SPME usage. Therefore, the aim of this paper is to exploit new SPME coating material with high selectivity, high sensitivity, thermal stability and long life. In this paper, we developed two kinds of coating material, and prepared three SPME fibers based on these materials.Nafion, a perfluorosulfonate ionomer, is widely applied in electrochemistry. Nafion solution is easy to form membrane by vaporizing, which mainly used as separating membrane in electrolytic cells, a solid polymer electrolyte in fuel cells and batteries, and electrode coating. Its resistance to chemical attack and thermal stability, in addition to its high mechanical strength, make it ideal for applications where SPME is required. We prepared Nafion fiber and Nafion/AC fiber. The coating methods are described in chapter 3 and chapter 4 in detail.Polypyrrole(Ppy) is one kind of conducting polymers. It has such good properties as high stability, strong adsorption, easy preparation, various derivatives, etc, which enable it a good candidate to be SPME coating material. Studies from foreign researchers show this material can extract not only volatile, less volatile compounds but also ions in extraction solution. The last chapter of this paper studied the methods for Ppy coating preparation under different electrochemical conditions. In the experiment, we polymerized pyrrole on carbon fiber to produce the new SPME fiber, i.e., a carbon fiber enwrapped in ploypyrrole. We also found this fiber has a porous structure film and good tenacity.The preparation conditions of these fibers and their properties were investigated respectively in each chapter, for example, extraction time, extraction temperature, desorption time, desorption temperature, extraction amounts, selectivity, detection limits, linear range andusing life. The extraction ability of Nafion and Nafion/AC fiber was compared with commercial fiber and the results show our fibers are better in specified aspects. The extraction and analysis of alcohols and esters are carried out respectively. The fibers were also used to determine methanol in wine, ethyl acetate in lake water, ethanol in pickles extraction solution. The results show that these fibers are suitable for the efficient extraction of these polar compounds.
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