HPLC-ICP-MS Rapid Determination of 4 Species of Selenium in Starchy Crops with Accelerated Solvent Extraction

A method was established for rapid simultaneous determination of 4 species of seleniumincluding selenate, selenite, (Methyl) seleno-cysteine and selenomethionine in starchy crops using accelerated solvent extraction (ASE) combined with HPLC-ICP-MS. The freeze-dried and crushed samples (0.300 0 g) was added into 0.03 g of protease XIV, and the mixture was rapidly extracted at 40℃ for 25 min with water as extraction agent. The extract was made up to 100.0 mL with water, and filtered by ultrafiltration centrifuge tube immediately. The 4 species of selenium were separated on a Hypersil Gold C₈ chromatographic column, with using 20 mmol·L^-1 potassium dihydrogen phosphate-0.1% (volume fraction) heptafluorobutyric acid-5% (volume fraction) methanol as mobile phase for isocratic elution. ICP-MS was used to determine the 4 species of selenium in the eluate. The results showed that the 4 selenium species were separated effectively in 6 min. Linear relationships between peak area and mass concentration of the 4 selenium species were kept in the definite range. Limits of detection were found in the range of 0.05-0.10 mg·kg^-1. Values of recovery obtained by standard addition method were in the range of 81.6%-110%, and RSDs (n=6) were in the range of 2.1%-11%.