Study of Selenium Speciation in Selenized Rice Using High-Performance Liquid Chromatography-Inductively Coupled Plasma Mass Spectrometer

On the basis of Osborne fractionation, albumin, globulin, prolamine, and gluletin in selenium (Se) rich rice were extracted with water, 2% NaCl solution, 70% alcohol, and 0.5% alkaline solution subsequently. The content of Se in these protein extracts was determined by inductively coupled plasma mass spectrometry (ICP-MS). The chemical forms of Se in albumin extract and enzymatic digests of rice were analyzed with a hyphenated technique of high performance liquid chromatography and ICP-MS. The Se content in four types of extracts shows an order of gluletin > prolamine > albumin > globulin. The protein with molecular weight of 12.6 kDa is the primary Se-containing protein in extracts of albumin, and the Se from selenocysteme is approximately 30% of the total Se present in the selenized rice.