【作者】 王喆；

【导师】 李方实；

【作者基本信息】 南京工业大学 ， 应用化学， 2003， 硕士

【摘要】 硒是人体的必须微量元素之一，对人体健康具有重大的意义。近年来，很多实验调查结果都表明，机体硒摄入水平与多种疾病的发生有关。在微量元素硒的性质不断被认识的今天，含硒材科尤其是含硒生物材料中硒的测定，在有关硒的研究中占有十分重要的地位。各种硒化合物的生理、生化作用、在环境中的迁移规律不仅取决于硒的总体水平，而且与硒存在的具体化学形态和各种化学形态的浓度密切相关。尽管在硒的分析以及形态分析方面已经做了大量的工作，但由于硒的生物化学作用以及对于人体健康的意义，发展实用的分析方法对环境中的硒进行监测，利用各种联用技术进一步探明不同形态存在的硒的生化行为，仍然意义重大。原子荧光法是上个世纪六十年代发展起来的分析技术，具有谱线简单、灵敏度高、检测限低和多元素分析的优点。氢化物发生的进样方法具有实现分析元素与基体的分离消除基体干扰、实现待测元素的预富集、进样效率高、易于实现自动化、进行价态分析等优点。本文运用氢化物发生－原子荧光法测定了食品中硒，创新之处在于研究了表面活性剂对硒的测定的影响，并在此基础上测定了康必硒中的Se（Ⅵ）、Se（Ⅳ），和有机硒。第一部分：建立了断续流动氢化物发生原子荧光法测定富硒食品中微量硒的方法。样品用硝酸高氯酸混酸消化，铁氰化钾为掩蔽剂，在优化的实验条件下，工作曲线在100μg/L范围内线性良好，相关系数为0.9999，方法的检测限为0.065μg/L，应用于测定鸡蛋、富硒米和富硒盐中微量硒，回收率分别为90.6％、98.5%和104.3％。 第二部分：先以正交实验对仪器和氢化物发生条件进行了优化，在优化的条件下研究了阴离子表面活性剂、阳离子表面活性剂和非离子表面活性剂对硒的测定的影响，发现在CTAB浓度为0.1～0.8×10-5mol/L时，荧光强度增加，与水相相比，增加幅度达到22.72%，提高了分析的灵敏度；CTAB 浓度为0.2×10-5mol/L时，检测限较之水相中显著降低，同时提高了共存离子的允许限量，尤其对Cu2+的作用更为显著。 把上述结果用于测定康必硒中的硒；确定了定量提取康必硒中硒的条件和提取<WP=5>率，以6mol/L的HCl定量还原Se（Ⅵ）为Se（Ⅳ），测定了康必硒中的Se（Ⅵ）、Se（Ⅳ）和有机硒，结果康必硒中99.5%以上的硒以有机硒的形式存在。更多还原

【Abstract】 Selenium is a necessary trace element for the health of people. In recent years, many investigations show that many diseases are related to intaking level of selenium. At today when selenium is known more clearly, the determination of selenium in selenium-containing materials and selenium-containing biological matairals become more important for the study of selenium. The roles of selenium in biological systems and geochemical cycle not only depend on the total content of selenium but also depend on the forms in which it is present and the content of these forms. Although many works have been done in the fields of determanation and speciation of selenium, developing applied method to detect selenium in environment, appling hyphenated techniques to prove up the biological behavior of different chemical and biological forms are significant. Atomic fluorescence spectrometry（AFS） is an analytical technique which have been developed since 1960’.The technique has many virtues such as simple spectral line,high sensitivity,low detection limit and multi-element analysis.Hydride generation（HG） thchnique has the virtues of separating from matrix,eliminating interference of matrix,enriching elements, high sampling efficiency, apting to realize automatic analysis,speciation.In this paper,hydride generation-atomic fluorescence spectrometry(HG-AFS) was used to determine selenium in foods;the innovation of the paper was that the influence of surfactant on the determination of selenium was studied and on the basis, Se（Ⅵ）、Se（Ⅳ）and organic selenium in Kangbixi were determined. Part Ⅰ：A method was developed for the determination of trace selenium in selenium-enriched foods by intermittent flow-hydride generation-atomic fluorescence spectrometry. Samples were digested with a mixture of nitric acid and perchloric acid, potassium ferricyanide acted as masking agent. Under the optimized conditions, the working curve was linear in the range of 100μg/L and the correlation coefficient was 0.9999. The detection limit was 0.065μg/L. When the method was applied to determine trace selenium in eggs, selenium-enriched rice, and selenium-enriched salt the recoveries were 90.6%, 98.5%, and 104.3% respectively.<WP=7> Part Ⅱ：Instrument and hydride generation conditions were optimized with orthogonal experiment;under optimized conditions,the influence of anionic surfactant,cationic surfactant and nonionic surfactant on the determination of selenium was studied; when the concentration of CTAB was 0.1～0.8×10-5mol/L,the intensity of signal was enhanced 22.72% compared with the intensity of signal in water media,so the sensitivity was improved.In the media of 0.2×10-5mol/L CTAB,a three-fold improvement in detection limit was obtained;at the same time, the levels of tolerance of interfering elements in the selenium determination were increased, the effect was even more remarkable for Cu2+. Selenium in Kangbixi was determined in the media containing 0.2×10-5mol/L CTAB.In order to quantitatively extract selenium in Kangbixi,the extracting condition and extracting percentage were investigated.Se（Ⅵ）was reduced to Se（Ⅳ）with 6mol/L HCl. Se（Ⅵ）、Se（Ⅳ）and organic selenium in Kangbixi were determined, as a result ,99.5% selenium in Kangbixi was organic selenium.更多还原