原子吸收法测定食品中微量硒

Determination of Trace Selenium in Foods by Atomic Absorption Spectrophotometry

原子吸收法测定微量硒被认为是最困难的技术之一，主要因为硒是一种易挥发元素。本文在前人工作的基础上，以Ｐｄ＋Ｍｇ混合金属为石墨炉原子吸收法测定硒的基体改进剂，提高了灰化和原子化温度，降低了基体干扰，提高了检测灵敏度；同时还对多种金属基体改进剂和复合金属基体改进剂在石墨炉测硒时的行为进行了全面考察，并详细讨论了铁对微量硒石墨炉测定的干扰情况。通过一系列试验，建立起一种石墨炉原子吸收法测定食品中微量硒的方法，方法特征量ｍ＿０＝２．６８ｎｇ／０．００４４Ａ，校准曲线在０－４００ｎｇ／ｍＬ间呈线性，相关系数ｒ＝０．９９９，回收率在８９．５％－１０６％之间且结果与氢化物原子吸收法一致。

Determination of trace selenium by atomic absorption spectrophotometry is considered as one of the most difficult technologies,because selenium is a volatile element.This paper used Pd+Mg as the matrix modifier to determine selenium by graphite furnace AAS to raise the pyrolysis & atomic temperatures,to reduce the matrix interferences and to raise detection sensitivity;meanwhile a number of metallic and complex metallic matrix modifiers have been studied for the climination of matrix effect in the determination of trace selenium by GF-AAS as well as interferences of iron.A method for determining trace selenium in foods by GF-AAS has been established by a series of experiments.The characteristic mass is 2.68ng/0.0044A,the standard curve is linear from 0 to 400ng/mL.The coefficient of correlation is 0.999.The recovery rates of the element are from 89.5% to 106% and the results are in conformity with those of hydride generation AAS.