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United States Department of Agriculture

Agricultural Research Service

Title: Selenomethionine Contents of Nist Wheat Reference Materials

Authors
item Wolf, Wayne
item GOLDSCHMIDT, ROBERT

Submitted to: Analytical and Bioanalytical Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 15, 2004
Publication Date: March 15, 2004
Citation: Wolf, W.R., Goldschmidt, R.J. 2004. Selenomethionine contents of nist wheat reference materials. Analytical and Bioanalytical Chemistry. 378(5):1175-1181.

Interpretive Summary: As the form in which Se occurs in foods and dietary supplements is important from a nutritional perspective, adding information about Se speciation to total Se values in available Reference Materials makes them more valuable in relevant analytical work. Wheat is an important source of Se in the diet. Values of the total selenium and selenomethionine (Semet) content of four wheat-based reference materials, available from NIST, have been obtained using gas chromatography-stable isotope dilution mass spectrometry methods. The total Se method is an established one, and the results obtained with it are consistent with previously assigned values for these materials. The Semet method (previously reported by our laboratory) is based on reaction with CNBr. Our data indicate that the four wheat Reference Materials (wheat gluten, durum wheat, hard red spring wheat, and soft winter wheat), though having a 30-fold range in total Se content, all have about 45 % of their total Se values in the form of selenomethionine. These data will be used by researchers in the public and private sectors interested in the species of selenium in foods.

Technical Abstract: Values of the total selenium and selenomethionine (Semet) content of four wheat-based reference materials, available from NIST, have been obtained using gas chromatography-stable isotope dilution mass spectrometry methods. The total Se method is an established one, and the results obtained with it are consistent with previously assigned values for these materials. The Semet method (previously reported by our laboratory) is based on reaction with CNBr. Our data indicate that the four wheat Reference Materials (wheat gluten, durum wheat, hard red spring wheat, and soft winter wheat), though having a 30-fold range in total Se content, all have about 45 % of their total Se values in the form of selenomethionine. Investigation of the CNBr-based method suggests that additional experiments are needed to verify that all selenomethionine in the wheat samples is accounted for, but also indicates that the values obtained are within 15 % of the true values. As the form in which Se occurs in foods and dietary supplements is important from a nutritional perspective, adding information about Se speciation to total Se values in available Reference Materials makes them more valuable in relevant analytical work.

Last Modified: 9/10/2014
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