蔬菜中硒总量及形态的氢化物发生-原子荧光光谱测定方法

采用氢化物发生原子荧光光谱法(HG-AFS)测定了几种蔬菜中的总硒含量，并测定了其中无机硒和有机硒的相对含量。实验优化了仪器测量参数，考察了载流盐酸和硼氢化钾浓度、样品介质盐酸浓度和残留硝酸浓度及干扰元素对测定的影响。结果表明：几种蔬菜中硒的含量都较低，而草菇的硒含量达到0.151 μg·g-1。此外，蔬菜中硒主要以有机硒的形态存在。方法的检出限为0.35 ng·g-1,加标回收率为97.6%～101%。实验方法操作简便、灵敏度高，结果令人满意。

Total Selenium and Se Species in Vegetables Measured with Hydride Generation-Atomic Fluorescence Spectrometry

The amounts of total selenium and Se-species including organic and inorganic selenium in vegetables were measured with the method of hydride generation-atomic fluorescence spectrometry. The instrumental parameters and analytical conditions were optimized. In order to obtain the maximum fluorescence signal, the effects of the concentrations of HCl and KBH₄ in carrier solution, the concentrations of HCl and HNO3 in sample medium, and the interference from foreign ion (Cu) on the signal were mainly investigated. Under the optimum conditions, the detection limit estimated with 3-fold standard deviation by 11 replicates of procedure blank was 0.35 ng·g-1. The recovery tested by adding standards ranged from 97.6% to 101%. After being digested with HNO₃ by microwave, selenium in several kinds of vegetables was measured. The results indicated that the total amounts of Se in the vegetable samples were low except straw mushroom, in which the content of Se was 0.151 μg·g-1 (dry weight). In addition, the species of organic selenium were the main existing forms in vegetables.