【作者】 柳诚；

【导师】 陈世忠；

【作者基本信息】 武汉工业学院 ， 应用化学， 2009， 硕士

【摘要】 现代科学技术的迅速发展不断向分析化学提出新的挑战,要求分析化学用更低的消耗、更简便的方法、更快的速度提供准确的有关物质成分、形态与结构等信息。由于分析对象越来越复杂,待测组分含量越来越低,尽管微电子技术的应用使分析仪器的性能大大改善,可以达到痕量甚至超痕量水平,然而对于复杂样品,由于基体效应和干扰物质的存在,在大多数情况下直接对样品进行分析常常很难得到满意的结果。因此,必须借分离富集技术,以提高分析方法的灵敏度、选择性和准确度。固相萃取分离富集技术因具有操作简单、富集倍数高、样品和试剂消耗少、无乳化现象、易于收集组分、对环境友好以及易于与不同的检测技术联用等优点,在样品前处理中得到了广泛的应用。在固相萃取分离富集中,固相吸附材料的选择非常重要。因此,寻找新的、性能优越的吸附材料一直是分析科学研究领域中的一个热点问题。纳米材料是近年来受到广泛重视的一种新兴功能材料,具有一系列新异的物理化学特性。如具有较高的比表面积、表面能和表面结合能等,其表面原子周围缺少相邻的原子,具有不饱和性,易与其它原子相结合而趋于稳定,具有很高的化学活性,因此,对金属离子具有很强的吸附能力和较大的吸附容量,是一种很有发展潜力的吸附材料。电感耦合等离子体质谱(ICP-MS)作为一种痕量、超痕量元素分析技术,具有检出限低、精密度高、动态线性范围宽、多元素同时测定等优点,在环境、食品、临床、生物、材料等领域里获得了广泛的应用。本论文的研究目的是:较系统地研究单壁碳纳米管对金属离子的吸附性能、主要影响因素及其相关规律性,在此基础上,将其应用于地质、环境和生物等样品中痕量/超痕量金属元素的分离富集与测定。主要研究内容概括如下:(1)以单壁碳纳米管为吸附材料,采用ICP-MS作为检测手段,研究了单壁碳纳米管对金属离子Cu、Co和Pb的吸附性能。考察了pH值、洗脱剂、共存离子等因素对吸附的影响,并将方法应用于实际样品分析。(2)以单壁碳纳米管为柱吸附剂,将微柱分离富集与ICP-MS联用,对稀土离子La、Gd、和Yb的吸附行为进行了研究,并将所建立的方法应用于生物和环境样品中稀土离子的分离富集与测定。(3)研究了在动态条件下单壁碳纳米管对贵金属离子Au、Pd的吸附性能,确定了最佳吸附和解吸条件,建立了单壁碳纳米管分离富集ICP-MS联用测定地质样品中痕量Au、Pd的新方法。更多还原

【Abstract】 With the rapid development of modern science and technology, there is an increasing demand for the information about the ingredient,species and structure of substances. In spite of the great improvement of instrumental power of detection at present ,direct determination of trace elements in extremely low concentration by modern analytical techniques is,in many cases, difficult.This is not only due to the insufficient sensitivity of the methods, but also the matrix interferences. To overcome these difficulties,the preliminary separation/preconcentration methods are still frequently required prior to the analysis for the improvement of sensitivity, selectivity and accuracy of analytical method.Solid-phase extraction(SPE) technique has become increasingly popular in trace elements separation/preconcentration due to its advantages of simple to operate, high preconcentration factor, low consumption of organic solvents, rapid phase separation and the ability of combination with different detection techniques. It should be pointed out that the choice of adsorbents for solid-phase extraction is decisive factor that affects analytical sensitivity and selectivity. Therefore, it has still been a very interesting research field to find new and effective adsorbentsNanometer material is a new function material that gained development and importance in recent years because of its special properties such as large specific surface area, surface energy and surface binding energy. One of the specific properties is that a high percent of the atoms of the nanometer particle is on the surface. The surface atoms are unsaturated and can therefore bind with other atoms easily, possess highly chemical activity. Consequently, nanometer materials can adsorb metal ions with high adsorption capacity. These facts imply that nanometer-size material may be a promising adsorption material for solid-phase extraction.As is well known, inductively coupled plasma mass spectrometry (ICP-MS)has become one of the most effective techniques for the determination of trace/ultra-trace elements due to its low detection limits, super high sensitivity,broad dynamic linear range and rapid multi-element detection capability. The aim of this dissertation is to systematically study the adsorption characteristics of the metal ions on single-walled carbon nanotubes by ICP-MS, and apply it to the separation/preconcentration of trace elements in real samples. The major contents are described as follows:(1) The adsorption behaviors of trace Cu, Co and Pb on single-walled carbon nanotubes were studied. The effects of pH, sample flow rate and volume, elution solution and interfering ions on the preconcentration and separation of analytes were examined in detail. The proposed method was applied to the preconcentration/separation and determination of trace Cu、Co and Pb in biological and environmental samples.(2) The adsorption characteristics of rare earth elements on single-walled carbon nanotubes(SWNTs)were studied, and the conditions for preconcentration/separation of trace elements were optimized and selected in detail. On the basis of the obtained experimental results, a new method of SWNTs preconcentration coupled with ICP-MS for simultaneous determination of rare elements in biological and environmental samples. was proposed.(3) A novel method was developed for the preconcentration of trace gold and palladium with a microcolumn packed with single-walled carbon nanotubes under dynamic conditions prior to their determination by ICP-MS. The conditions of preconcentration were investigated. The proposed method was applied to the analysis of gold and palladium in geological samples.更多还原