SPECIATION OF SELENOAMINO ACIDS AND ORGANOSELENIUM COMPOUNDS IN SELENIUM-ENRICHED YEAST USING HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY INDUCTIVELY-COUPLED PLASMA-MASS SPECTROMETRY

As part of an ongoing study to identify selenium compounds with cancer chemopreventive activity, selenium-enriched yeast was analyzed by HPL C-ICP-MS. More than twenty selenium-containing species were found in h ot water and enzymatic hydrolysis extracts of the yeast, Trifluoroacet ic acid was used as an ion-pairing agent in a water-methanol mobile ph ase with reversed-phase chromatography on an octylsilane stationary ph ase. The presence of selenocystine, selenomethionine and methylselenoc ysteine was confirmed by comparative retention of standards. The colum n efficiency was 8500 theoretical plates and the mobile-phase was comp atible with standard ICP-MS operating conditions.