Speciation of Selenoamino Acids and Organoselenium Compounds in Selenium-enriched Yeast Using High-performance Liquid Chromatography–Inductively Coupled Plasma Mass Spectrometry

Abstract
As part of an ongoing study to identify selenium compounds with cancer chemopreventive activity, selenium-enriched yeast was analyzed by HPLC–ICP-MS. More than twenty selenium-containing species were found in hot water and enzymatic hydrolysis extracts of the yeast. Trifluoroacetic acid was used as an ion-pairing agent in a water–methanol mobile phase with reversed-phase chromatography on an octylsilane stationary phase. The presence of selenocystine, selenomethionine and methylselenocysteine was confirmed by comparative retention of standards. The column efficiency was 8500 theoretical plates and the mobile phase was compatible with standard ICP-MS operating conditions.