HG-AFS Determination of Total and Inorganic Selenium in North Cordyceps

The sample of north cordyceps was digested with mixed acid of HNO3-HClO4 (5+1), and the content of total selenium in sample solution was determined by HG-AFS. The sample was leached with HCl, and the content of inorganic selenium was determined by HG-AFS. Hydride of Se ion was generated by reacting with 20 g·L-1 KBH4 solution (dissolved in 5 g·L-1 KOH solution). Flow-rates of 500 mL·min-1 for carrier gas and 1 000 mL·min-1 for shielding gas were taken in the analysis. Linear relationship between values of fluorescence intensity and mass concentration of Se found was in the range within 100 μg·L-1, with detection limit (3s/k) of 0.2 μg·L-1. The proposed method was applied to the determination of Se in north cordyceps, giving values of RSD′s (n=5) in the range of 3.4%-3.9% for total Se and average recovery of 103% for inorganic Se.