HG-AAS Determination of Micro-amount of Selenium in Tatary Buckwheat with Microwave Assisted Sample Digestion

The sample of Tatary buckwheat was digested with HNO3, and the stable species of Se(Ⅵ) in the solution was reduced to Se(Ⅳ) by 6 mol·L-1 HCl. Selenium was determined by hydride generation-atomic absorption spectrometry (HG-AAS) with KBH4 as reducing reagent and HCl(1+99) solution as carrying solution. Linear relationship between values of absorbance and mass concentration of selenium was obtained in the range of 5-40 μg·L-1, with detection limit (3S/N) of 0.083 μg·L-1. Three samples of Tatary buckwheat were analyzed by the proposed method, value of average recovery found by standard addition method was 97.3%.