Determination of selenium species in cereal food with ultrasonic enzyme extraction and high performance liquid chromatography-inductively coupled plasma mass spectrometry

  Objective  To detect selenium species in cereal food using high performance liquid chromatography-inductively coupled plasma mass spectrometry (HPLC-ICP-MS).

  Methods  Hamilton PRP-X100 anion exchange column was used as analytical column; 40 mmol/L diammonium phosphate (pH = 5.0) and 60 mmol/L diammonium phosphate (pH = 6.0) were used as mobile phase for gradient elution. Baseline separation of selenocysteine (SeCys₂), methylselenocysteine (MeSeCys), selenite Se(IV), selenomethionine (SeMet), and selenate Se(VI) were completed in 16 minutes. Ultrasonic-assisted enzyme extraction was used to extract selenium species in cereal food samples.

  Results  The method detection limit for SeCys₂, MeSeCys, Se(IV), SeMet, and Se(VI) were 2.5, 5.0, 2.5, 10.0, and 5.0 μg/kg, respectively. The linear correlation coefficients (r) were all greater than 0.999 in the range of 0.5 – 200.0 μg/L for the detections.

  Conclusion  Selenomethionine is a main selenium species, with a small amount of selenocystine, inorganic selenium and some unknown selenium compounds being detected, in cereal food.