【作者】 王雪芹；

【导师】 殷学锋；

【作者基本信息】 浙江大学 ， 分析化学， 2008， 硕士

【摘要】 砷大量存在于自然环境中,具有很高的毒性,并且易于在有机体中聚积,因此对痕量砷的测定依然是一个持续的并且备受关注的挑战。无机砷主要以As~Ⅲ和As~V的形式存在,具有高度的毒性,大量样品中砷的一些化合物均需在低浓度下进行测定,因为砷在实际样品中的含量很低。因此需要有精益的分析方法和分析仪器。氢化物发生—原子荧光光谱法具有灵敏度高、操作简单、成本低等优点,在易形成氢化物的元素的测定中得到了广泛的应用。第一章对砷的分析方法、氢化物发生法、原子荧光光谱法以及原子荧光技术的研究与应用发展进行了综述。第二章研究了氢化物发生—原子荧光法测定砷时消解液中的亚硝酸和过量的硝酸对测定的干扰,首次提出微波消解样品,尿素除去微波消解液中的亚硝酸,氢氧化钠中和微波消解液中过量的硝酸,用盐酸调节pH值后,L—半胱氨酸在低酸度下预还原砷(Ⅴ)到砷(Ⅲ)的预处理方法,避免了赶酸所引起的样品的玷污和由于挥发产生的待测元素的损失。同时避免了对环境的污染和工作人员身体健康的危害,大大减少了氢化物发生—原子荧光法测定砷的时问。实现了食品中痕量砷的准确、快速地测定。更多还原

【Abstract】 There is a continuing interesting challenge in the trace determination of arsenic because of its high toxicity and ability to bioaccumulate in many organisms and its abundance in all environmental compartments. The high toxicity of arsenic (As^III and As^V, which together constitute inorganic arsenic) and some of its compounds requires its determination at very low concentrations in a variety of samples. Since the arsenic levels in real samples are very low, state-of-the-art enrichment methods and instrumentation are required. Hydride generation atomic fluorescence spectrometry （HG-AFS） has been used for determination of hydride-forming elements because of its high sensitivity, simplicity, and low costs.In Chapter I, the methods for determination of arsenic, hydride generation and atomic fluorescence spectrometry with its research and application were reviewed.In Chapter II, a novel pretreatment method without evaporating and exhausting the excess nitric acid used for digesting biological sample was developed based on the evaluation of the interference of nitrite and nitric acid on the determination of arsenic using HG-AFS. After microwave sample digestion, the interference from nitrite ion generated during sample digestion was removed by adding urea. The excessive nitric acid was neutralized by sodium hydroxide. L-cysteine was used to prereduce As（V） to As（III） in low hydrochloric acid concentration. The pretreatment mothod is fast and accurate and was successfully applied to the determinationof As in a variety of biological samples. In addition, the proposed pretreatment method can prevent sample contamination and loss during exhausting the excess nitric acid . The experimental environment and hazards to staff’s health are also greatly improved.更多还原