紫外光诱导化学蒸气发生—电感耦合等离子体质谱分析法测定痕量锇和铅

发布时间：2018-03-22 00:29

本文选题：电感耦合等离子体质谱　切入点：紫外光诱导化学蒸气发生　出处：《成都理工大学》2017年硕士论文　论文类型：学位论文

【摘要】：进一步提高元素分析的灵敏度,降低分析方法的检出限,并将其应用于复杂基体样品中痕量及超痕量元素的准确分析,一直是原子光谱的主要研究方向。电感耦合等离子体质谱(ICP-MS)作为元素分析的重要技术,具有灵敏度高、光谱干扰小、分析速度快、多元素同时分析等优点。紫外光诱导化学蒸气发生(PVG)可将目标分析物通过光化学反应转化为挥发物形态,作为原子光谱的进样手段,具有进样效率高、方法简单、绿色和抗干扰能力强等优点。本文中,我们发展了新型的PVG技术,将其与ICP-MS联用,大大提高了目标分析物的进样效率,降低了样品基体对分析物准确测定的影响。方法成功应用于环境样品中锇(Os)和铅(Pb)的分析。具体工作包括以下两方面内容:(1)Re-Os同位素体系在地表过程研究领域中的应用越来越广泛。由于Os在地质体系中的自然丰度很低及其在低温下易形成挥发性的四氧化锇(OsO4)等特点,为Os的测定带来了巨大的挑战。目前,Os的分析过程常伴随着灵敏度低、提取步骤复杂、流程空白高以及“记忆效应”严重等问题,因此发展准确和高灵敏的测定Os元素分析方法具有重要的意义。本文利用PVG结合ICP-MS,用于环境水样中Os的测定。通过使用5%的硝酸作为氧化剂,在紫外光的辐射下,使Os有效转化为具有挥发性的OsO4,并采用ICP-MS进行分析,这大大提高了分析的灵敏度,降低了分析的流程空白;文中还利用5%的氨水作为洗脱液,有效消除了传统Os分析中严重的“记忆效应”对分析准确度的影响。方法的检出限可达0.8 pg g-1。该方法具有灵敏度高和操作流程简单、安全等特点,适用于环境以及地质样品中痕量Os的测定。(2)Pb由于其毒性、不可降解性及生物累积性,对海洋生态系统具有潜在威胁。阐明海水中Pb的分布及浓度特征对于确定污染物来源和污染物防治具有至关重要的作用。ICP-MS是环境样品中痕量元素分析最常用的方法。然而,海水样品中Pb浓度极低及其高盐的样品基体为Pb的直接测定带来很大挑战。本文利用镍离子辅助PVG结合ICP-MS,用于海水样品中的痕量Pb测定;通过使用15μg g-1镍离子和10%(v/v)甲酸的混合物作为光化学还原介质,有效消除样品基体对Pb的PVG抑制的影响,使得直接测定海水样品中的Pb成为可能。该方法的检出限可达0.003 ng g-1,该方法具有灵敏、简单的特点,适用于海水中痕量/超痕量Pb的分析。
[Abstract]:Further improving the sensitivity of element analysis, reducing the detection limit of the analytical method, and applying it to the accurate analysis of trace and ultra-trace elements in complex matrix samples, Inductively coupled plasma mass spectrometry (ICP-MS) is an important element analysis technique with high sensitivity, low spectral interference and fast analytical speed. UV induced chemical vapor generation (PVG) can transform the target analyte into volatile form by photochemical reaction. As an injection method of atomic spectrum, it has high injection efficiency and simple method. In this paper, we develop a new type of PVG technology and combine it with ICP-MS to greatly improve the sample injection efficiency of the target analyte. The method has been successfully applied to the analysis of osmium (Osn) and lead (Pb) in environmental samples. The specific work includes the following two aspects. Because of the low natural abundance of Os in geological systems and the volatile osmium tetroxide OsO4 at low temperature, At present, the analytical process of Os is often accompanied by the problems of low sensitivity, complex extraction steps, high process blank and "memory effect". Therefore, it is of great significance to develop an accurate and highly sensitive analytical method for the determination of Os elements. In this paper, PVG combined with ICP-MSis is used for the determination of Os in environmental water samples. By using 5% nitric acid as oxidant, under ultraviolet radiation, The Os was effectively converted to OsO4 with volatility and analyzed by ICP-MS, which greatly improved the sensitivity of the analysis, reduced the blank of the analysis process, and used 5% ammonia water as the eluant. The influence of "memory effect" in traditional Os analysis on analytical accuracy is effectively eliminated. The detection limit of the method can reach 0.8 PG g-1.This method has the characteristics of high sensitivity, simple operation flow and safety, etc. Suitable for the determination of trace amounts of Os in environmental and geological samples due to their toxicity, non-degradability and bioaccumulation, Potential threats to marine ecosystems. Clarifying the distribution and concentration characteristics of Pb in seawater is essential for determining the source and prevention of pollutants. ICP-MS is the most commonly used method for the analysis of trace elements in environmental samples. The direct determination of Pb in seawater samples with very low Pb concentration and high salt content is a great challenge. In this paper, nickel ion-assisted PVG combined with ICP-MS is used for the determination of trace Pb in seawater samples. By using the mixture of 15 渭 g / g nickel ion and 10 渭 g / v / v) formic acid as photochemical reduction medium, the effect of sample matrix on PVG inhibition of Pb was effectively eliminated. It is possible to directly determine Pb in seawater samples. The detection limit of this method is up to 0.003 ng g ~ (-1). The method is sensitive and simple. It is suitable for the determination of trace / ultra-trace Pb in seawater.
【学位授予单位】：成都理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X834;O657.63

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