Characterization of Selenium Species in Brazil Nuts by HPLC-ICP-MS and ES-MS

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• 作者：Anne P. Vonderheide ; Kazimierz Wrobel ; Sasi S. Kannamkumarath ; Clayton B'Hymer ; Maria Montes-Bayó ; n ; Claudia Ponce de Leó ; n ; and Joseph A. Caruso
• 刊名：Journal of Agricultural and Food Chemistry
• 出版年：2002
• 出版时间：September 25, 2002
• 年：2002
• 卷：50
• 期：20
• 页码：5722 - 5728
• 全文大小：83K
• 年卷期：v.50,no.20(September 25, 2002)
• ISSN：1520-5118

文摘

Brazil nuts have been classified as the foodstuffs that contain the highest level of unadulteratedselenium, an essential trace element that appears to prevent cancer. To date, characterization of theselenium species in brazil nuts has not yet been investigated. In this work, various sample preparationapproaches, including microwave extractions and enzymatic treatments, are examined with the goalof species preservation and subsequent selenium speciation; of these approaches, an enzymatictreatment with Proteinase K proved most effective. High-performance liquid chromatography (HPLC)separation strategies and inductively coupled plasma mass spectrometry (ICP-MS) detection schemeswill also be presented. Extracts are evaluated against available standards for the commerciallyobtainable seleno-amino acids, selenomethionine (SeMet), selenoethionine (SeEt), and selenocystine(SeCys); selenomethionine was demonstrated to be the most abundant of these seleno-amino acids.Further characterization of unidentified selenium-containing peaks is attempted by the employmentof several procedures, including electrospray-mass spectrometry (ES-MS). A peptide structure wasidentified; however, this was considered a tentative proposal due to the large background producedby the extremely complicated brazil nut matrix.Keywords: Selenium speciation; brazil nuts; HPLC-ICP-MS; ES-MS