【作者】 张莉；

【导师】 常希俊；

【作者基本信息】 兰州大学 ， 分析化学， 2012， 博士

【摘要】 金属离子污染存在于人类生活的各个领域,严重威胁到了人类的健康及生命。有效检测及治理环境中的痕量金属污染物就成为环境分析化学工作者所面临的一大挑战。固相萃取技术(SPE)是目前预处理样品技术中最为灵活、高效的的一种手段。对于固相萃取技术而言,吸附剂的选择决定着方法的回收率和富集因子。为了提高固相萃取技术的选择性,一般通过物理或者化学手段对吸附剂的表面进行修饰。本论文致力于合成新型的固相萃取剂并将其用于环境样品中痕量金属离子的分离富集,主要的研究工作如下：1、制备一种新型的固相萃取剂(三乙四胺修饰活性炭),并通过红外光谱进行表征。ICP-OES检测表明：在pH4时,这种萃取剂对Cr(Ⅲ)、Fe(Ⅲ)和Pb(Ⅱ有很好的吸附效果；洗脱条件为0.5M HCl;吸附剂对Cr(Ⅲ)、Fe(Ⅲ)和Pb(Ⅱ)的饱和吸附容量分别是34.6、36.5和51.9mg g-；检出限分别是是0.71、0.35和0.45ng mL-1；相对偏差分别为3.7%、2.2%和2.5%。将新型吸附剂应用于实际样品的测定,结果令人满意。2、用罗丹明6G修饰活化的活性炭合成制备了新型吸附剂AC-Rh6G,并建立了很好的富集分离Cr(Ⅲ)、Cu(Ⅱ)、Cd(Ⅱ)和Pb(Ⅱ)的方法。该方法对Cr(Ⅲ)、Cu(Ⅱ)、Cd(Ⅱ)和Pb(Ⅱ)具有较大的吸附容量和富集因子,并且大量共存的干扰物质对该方法影响不大。此外,该吸附剂的制备过程相对简单和方便。该方法已经成功用于实际样品和水样的检测,结果令人满意。3、用硫代二酰肼修饰凹凸棒合成了新型的固相萃取剂,实验结果表明这种新型萃取剂对Au(Ⅲ)有很好的分离富集效果。此外,吸附剂的合成过程相对简单和方便,和其他吸附剂相比具有较大的吸附容量。在实际水样和标样的应用中,均得到很好的测试结果。4、用1-氨基-2-萘酚-4-磺酸钠盐修饰活性炭合成了新型的固相萃取剂,合成过程相对简单方便,并建立了新的分离富集Au(Ⅲ)的方法,和其他文献报道过的吸附剂相比具有比较好的吸附容量。在实际水样和标样的应用中,均得到很好的测试结果。5、在pH7.4,铕(Ⅲ)与蛋白质作用引起共振散射强度在250-600nm范围中明显增强。当pH值大于蛋白质等电点时,蛋白质带负电荷,蛋白质通过静电作用和铕(Ⅲ)结合,由于这个实验现象,我们建立了一种新的简单、灵敏度高的检测蛋白质含量的方法。在优化条件下,共振散射强度分别与血红蛋白(0.16-30.00ug mL-1)和丙种球蛋白的浓度(0.05-20.00ug mL-)成正比,对血红蛋白和丙种球蛋白的检出限分别是80ng mL-1和22ng mL-1,而且本方法受干扰物质(金属离子、氨基酸)影响不大。应用在合成样品中结果令人满意。更多还原

【Abstract】 The toxicity and the effect of trace elements on human health and the environment are receiving increasing attention in pollution and nutritional studies. Therefore, it is crucial to develop simple, rapid, and efficient methods for monitoring metal ions in the environment. In SPE procedure, the choice of appropriate adsorbent is a critical factor to obtain full recovery and high enrichment factor. To improve the selectivity, a chemical or physical modification of the sorbent surface with some organic compounds, is usually used to load the surface with some donor atoms such as oxygen, sulfur, nitrogen and phosphorus. Based on it, this research paper is devoted to the design, synthesis and application of newly selective solid-phase extractors in order to pre-concentration and separation of trace metal ions. The detailed novelty of this study has been listed in the following:1. A new selective solid-phase extractant using activated carbon as matrix which was purified, oxidized and modified by triethylenetetramine (AC-TETA) was prepared and characterized by FT-IR spectroscopy. At pH4, quantitative extraction of trace Cr(Ⅲ), Fe(Ⅲ) and Pb(Ⅱ) was obtained and determined by inductively coupled plasma optical emission spectrometry (ICP-OES). Complete elution of the adsorbed metal ions from the sorbent surface was carried out using0.5mol L-1HCl. The maximum static adsorption capacity of sorbent for Cr(Ⅲ), Fe(Ⅲ) and Pb(Ⅱ) was34.6,36.5and51.9mg g-1, respectively. The time of quantitative adsorption was less than2min. The detection limits of the method was found to be0.71,0.35and0.45ng mL-1for Cr(Ⅲ), Fe(Ⅲ) and Pb(Ⅱ), and the relative standard deviation (RSD) was3.7%,2.2%and2.5%, respectively. Moreover, the method was free from interference with common coexiting ions. The method was also successfully applied to the preconcentration of trace Cr(Ⅲ), Fe(Ⅲ) and Pb(Ⅱ) in synthetic samples and a real sample with satisfactory results.2. In this study, Cr(lII), Cu(Ⅱ), Cd(Ⅱ) and Pb(Ⅱ) have been preconcentrated and separated by a new sorbent using rhodamine6G modified oxidized activated carbon and characterized by Fourier transform infrared spectra. At pH4, quantitative extraction of trace Cr(Ⅲ), Cu(Ⅱ), Cd(Ⅱ) and Pb(Ⅱ) was obtained and determined by ICP-OES. The adsorbed metal ions were completely eluted by1.0mol L-1HCl. The method was free from interference with common coexisting ions. The maximum adsorption capacity of the adsorbent at optimum conditions was found to be37.8,47.8,56.5and41.7mg g-1for Cr(Ⅲ), Cu(Ⅱ), Cd(Ⅱ) and Pb(Ⅱ) at pH4, respectively. The detection limits of the method were under0.35ng mL"1and the relative standard deviations were lower than3.5%(n=11). The method was validated using a standard reference material, and has been applied for the determination of trace Cr(Ⅲ), Cu(II), Cd(Ⅱ) and Pb(Ⅱ) in biological and natural water samples with satisfactory results.3. The study on the high efficiency of triocarbohydrazide modified attapulgite as solid-phase extractant for preconcentration of trace Au(Ⅲ) prior to the measurement by ICP-OES has been reported. Experimental conditions for effective adsorption of trace levels of Au(Ⅲ) were optimized with respect to different experimental parameters using batch and column procedures in detail. At pH3, Au(Ⅲ) could be quantitatively adsorbed on the new sorbent, and the adsorbed Au(Ⅲ) could be completely eluted from the sorbent surface by2.0mL1.0mol L-1of HCl+2%CS(NH2)2solution. An enrichment factor of150was accomplished. Moreover, common interfering ions did not interfere in both separation and determination. The maximum adsorption capacity of the sorbent for Au(Ⅲ) was found to be66.7mg g-1. The detection limits (3σ) of this method was0.32μg L-1and the relative standard deviation (R.S.D.) was3.3%(n=8). The method, with high selectivity, sensitivity and reproducibility, was validated using certified reference materials, and had been applied for the determination of trace Au(Ⅲ) with satisfactory results.4. A new method of separation, preconcentration and determination of trace gold(Ⅲ) in water samples was developed based on utilized1-amino-2-naphthol-4-sulfonate modified activated carbon as a solid-phase sorbent and measured by ICP-OES. The new sorbent was confirmed by Fourier transform infrared spectra. Experimental conditions for effective adsorption of trace gold(Ⅲ) were optimized in details. At pH3, gold(Ⅲ) could be quantitatively adsorbed on the new sorbent, and the adsorbed gold(Ⅲ) could be completely eluted from the sorbent surface by2.0mL of1.0mol L-1of HC1+2%CS(NH2)2. An enrichment factor of200was accomplished. The maximum adsorption capacity of the sorbent for gold(Ⅲ) was found to be32.3mg g-1. Moreover, common electrolytes did not interfere with the adsorption and determination of the analytes. The detection limit (3σ) of this method was found to be0.26ug L-1, and the relative standard deviation (R.S.D.) was3.1%(n=8). The method, with high certified selectivity, sensitivity and reproducibility, was satisfactorily applied to determinate a reference materials and water samples.5. At pH7.4, the resonance light scattering (RLS) intensity of the interaction of europium(Ⅲ) with proteins was obviously enhanced in wavelength range of250-600nm. When the pH value is higher than the isoelectric point of protein in Palitzsch buffer solution (pH7.4), protein takes negative charge. So the electrostatic interaction between europium(Ⅲ) and proteins may occur. Based on the phenomenon, a new simple, sensitive and selective method for the determination of proteins has been developed. Under the optimum condition, the enhanced RLS intensities were proportional to the proteins concentration over the ranges0.16-30.00and0.05-20.00ug mL-1for hemoglobin (Hb) and immunoglobulin G (IgG), respectively. The corresponding limits of detection were80and22ng mL-1for Hb and IgG, respectively. Moreover, the method was free from interference with many metal ions and animo acids. Synthetic samples were satisfactorily determined with the recovery of97.5-103.2%.更多还原