Simultaneous quantification of the speciation of inorganic selenium and Se amino acids in food by high performance liquid chromatography combined with inductively coupled plasma mass spectrometry

A new method based on high performance liquid chromatography combined with inductively coupled plasma mass spectrometry( HPLC- ICP- MS) for selenium speciation of inorganic selenium and Se amino acids has been developed. The different parameters affecting extraction efficiency and the retention behaviors of six target selenium species including the effect of p H and concentration of mobile phase,methanol content,flow rate and column temperature had been studied. Under the optimal condition of the mobile phase of 7.5 mmol / L diammonium phosphate buffer solution( p H11.0) with flow rate of0.60 m L / min,six target selenium species including Se O_3~(2-)( Se( IV)),Se O_4~(2-)( Se( Ⅳ)),L- Selenocystine( Se Cys2),DLSelenomethionine( Se Met),Se- methylseleno- L- Cysteine( Me Se Cys),Seleno- D,L- Ethionine( Se Et) were separated completely.The limits of detection for the target compounds were varied from 0.15 to 0.35 μg Se / L and the calibration curves were linear in the range of 2.0~2500 μg Se / L for Me Se Cys and Se Cys2,1.2~1200 μg Se/L for Se( Ⅳ) and Se( Ⅵ),1.5~1500 μg Se / L for Se Met and 2.2~2200 μg Se / L for Se Et with good correlation coefficient( R~2≥0.9997).The recoveries at three spike levels ranged from 80.8% to 106.7% with the relative standard deviations( RSDs,n = 3) of 4.7~9.6%.The method was found to be simple,rapid,efficient and inexpensive,and provided an accurate and sensitive detection platform for elemental speciation in food samples.