【作者】 战锡林；

【导师】 陈世忠；

【作者基本信息】 武汉工业学院 ， 应用化学， 2008， 硕士

【摘要】 随着现代环境科学、生命科学等学科的发展,人们发现元素的毒性与其存在形态密切相关,仅测量体系中元素的总量已不能满足研究该元素在体系中的生理、毒理作用的需要,因此提出了元素形态分析的概念。元素形态分析一般需要采用分离富集技术进行样品预处理,然后用高灵敏度的检测仪器进行测定。固相萃取作为一种常用的分离富集技术,具有较高的富集倍数、选择性好、有机溶剂消耗量少、能处理小体积样品、可重复使用吸附材料、操作简单、易于实现自动化等优点,在样品前处理中得到了广泛的应用。固相萃取中吸附材料的选择非常重要,直接关系到方法的灵敏度和选择性。因此,寻找新的吸附材料一直是分析科学研究领域中的一个热点问题。纳米碳纤维作为一种新型的纳米碳材料,具有较高的比表面积、表面能和表面结合能等,对许多金属离子具有较强的吸附能力,是一种颇具潜力的分离富集材料。电感耦合等离子体质谱法(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、分析速度快、线性范围宽和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,用纳米碳纤维作为固相吸附材料,以电感耦合等离子体质谱为检查手段,系统地研究了纳米碳纤维对铬、锰、砷三种元素不同价态的吸附性能、主要影响因素及其相关规律性,并将所建立的方法用于生物和环境样品中相关元素的形态分析。主要研究内容概括如下:(1)以纳米碳纤维为吸附剂,将微柱分离富集与ICP-MS联用,对Cr(Ⅲ)和Cr(Ⅵ)的吸附行为进行了研究,考察了影响吸附的主要因素,建立了Cr(Ⅲ)和Cr(Ⅵ)分析的新方法。(2)将微柱分离富集与ICP-MS联用,探讨了纳米碳纤维对Mn(Ⅱ)和Mn(Ⅶ)的吸附行为,考察了pH值、洗脱剂、共存离子等因素对吸附的影响,并用所建立的方法测定了实际样品中的Mn(Ⅱ)和Mn(Ⅶ)。(3)用纳米碳纤维作为吸附剂,以ICP-MS作为检测手段,研究了纳米碳纤维在APDC存在下对As(Ⅲ)和As(Ⅴ)的吸附行为,考察了影响吸附的主要因素,并将所建立的方法应用于实际样品中As(Ⅲ)和As(Ⅴ)的分析。更多还原

【Abstract】 With the development of environmental science and biological science, there is an increasing demand for the information about speciation because the different chemical forms of an element have different effects on human health, the environment and the ecosystems. Therefore, the separation and determination of elemental species is of great importance. In general, in order to obtain the data about the chemical form of elements, the separation and preconcentration are usually required before analysis by instruments.Solid phase extraction(SPE) as a separation and preconcentration technique has become increasingly popular in the pretreatment of samples 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. The choice of adsorbents for SPE is very important as it is decisive and direct factor that affects analytical sensitivity and selectivity. Therefore, it has still been an interesting research field to find new and effective adsorbents nowadays. Carbon nanofibers(CNFs), as a novel and interesting carbon material, have very attractive features:small size, large specific surface area, excellent mechanical strength, highly chemical stability, and unique electrical property. Their surface properties can be modified through different treatments to satisfy special needs. These make them a promising candidate as adsorbers for solid phase extraction. As is well know, inductively coupled plasma mass spectrometry (ICP-MS) has become one of the most appropriate 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 use a microcolumn packed with CNFs coupled to inductively coupled plasma mass spectrometry (ICP-MS) for the speciation analysis of elements in real samples. The major contents are described as follows:(1) The adsorption characteristics of Cr(Ⅲ) and Cr(Ⅵ) on CNFs were investigated systematically. Based on the obtained results,a novel method was developed for the speciation of chromium by a microcolumn packed with CNFs as adsorbent coupled with ICP-MS. The proposed method has been applied to the determination of the chromium in certified materials, and chromium species in water samples with satisfactory results.(2) The adsorption behaviors of Mn(Ⅱ) and Mn(Ⅶ) on CNFs under dynamic conditions were studied systematically. The main factors influencing preconcentration and determination of the analytes have been examined in detail. A novel method with carbon nanofibers(CNFs) as a solid phase extraction adsorbent for the preconcentration and determination of Mn(Ⅱ) and Mn(Ⅶ) was developed by inductively coupled plasma mass spectrometry (ICP-MS) detection.(3) A new method for the separation/preconcentration of As(Ⅲ) and As(Ⅴ) with a microcolumn packed with carbon nanofibers is described for the determination by inductively coupled plasma mass spectrometry in the presence of APDC. The effects of pH, sample flow rate and volume, elution solution and interfering ions on the adsorption of analytes were examined in detail. The proposed method was applied to the determination of As(Ⅲ) and As(Ⅴ) in real samples with good results.更多还原