Abstract:

A reversed phase-high performance liquid chromatography (RP-HPLC) method for the determination of organic
selenium compounds in selenium-enriched Aspergillus oryzae was established. The extraction of organic selenium compounds
from samples was performed through hydrolysis with 6 mol/L HCl solution for 48 h at 50 ℃. After pre-column derivatization
with 4-chlorine-3,5-dinitrobenzotrifluoride (CNBF), the derivatives were separated on a C18 reversed-phase column through
gradient elution with acetonitrile-water and pH 6.8 acetic acid-sodium acetate buffer solution. UV detection was carried
out at 240 nm. The organic selenium compound in selenium-enriched A. oryzae was mainly selenocystine (SeCys2).
The limit of detection (LOD) (RSN = 3) was 0.680 mg/L and the limit of quantitation (LOQ) (RSN = 10) was 2.244 mg/L.
The linear range was 5.0–100 mg/L. The recoveries were in the range of 94.8%–105.8% and selenium-enriched A. oryzae
contained 1.25 mg/g selenocystine. This method is simple, sensitive and accurate, and could be used to determine organic
selenium compounds in selenium-enriched A. oryzae and related products.

Key words: selenium-enriched Aspergillus oryzae, organic selenium, selenoamino acids, pre-column derivatization-RP-HPLC