悬浮进样-氢化物发生原子荧光法用于面粉和富硒盐中微量硒形态分析

Speciation Analysis of Trace Selenium in Flour and Selenium Rich Salt by Slurry Sampling and Hydride Generation Atomic Fluorescence Spectrometry

为了探索悬浮进样-氢化物发生原子荧光法直接测定总Se、无机Se和Se(Ⅵ)的新方法。样品中的总硒以5mL浓盐酸提取,用悬浮进样-氢化物发生原子荧光法加以测定;以环己烷萃取分离无机硒和有机硒,水相中的无机硒在浓盐酸量为20%(V/V)的介质中以悬浮进样-氢化物发生原子荧光法加以测定,而水相中的Se(Ⅵ)在5g/L亚硫酸钠溶液中以同样的方法加以测定。利用差减法求得有机硒和Se(Ⅳ)的含量。结果表明,硒的检出限(RSN=3)为0.10μg/L,回收率为90.7%～107%,相对标准偏差(RSD,n=5)为0.7%～1.9%。本方法具有准确、操作简易、快速、灵敏度高等优点,可用于小麦面粉、大米面粉和富硒盐中总硒、无机硒和Se(Ⅵ)的测定。

A new method was developed for directly determining total Se, inorganic Se and Se（Ⅵ） using slurry sampling-hydride generation atomic fluorescence spectrometry （SS-HGAFS）. For total Se determination, samples were extracted with 5 mL of concentrated HCl, followed by SS-HGAFS analysis. Cyclohexane extraction was used for the separation between inorganic Se and organic Se, and total inorganic Se and Se（Ⅵ） dragged into the water phase were determined by SS-HGAFS in concentrated HCl medium in the absence and presence of 5 g/L Na2SO3, respectively. Organic Se could be calculated by the difference between total Se and inorganic Se, and Se（Ⅳ） by difference of the inorganic Se and the Se（Ⅵ）. The method detection limit （RSN = 3） was 0.10 μg/L for Se. Mean spike recoveries for total Se, total inorganic Se and Se（Ⅵ） in real samples of wheat flour, rice flour and Se rich salt were between 90.7% and 107%, with a relative standard deviation （RSD） ranging from 0.7% to 1.9%. The proposed method has the characteristics of accuracy, easy operation, rapidity and high sensitivity, and is most suitable for the speciation analysis of selenium in real samples.