Analytical selenoamino acid studies by chromatography with interfaced atomic mass spectrometry and atomic emission spectral detection

摘要

Consumption of selenium enriched plants oryeast-based nutritional supplements has been reported toprovide anticarcinogenic benefits which are seleniumcompound dependent. Separation and identification ofthese selenium compounds is critical to understand the activity.Plants and yeast convert inorganic selenium in thesoil or growth media into organoselenium compounds,probably following a route similar to the sulfur assimilatorypathway. Non-volatile selenium compounds producedinclude selenoamino acids, some of which haveshown anticarcinogenic activity. Volatile compounds producedby chemical reaction of involatile precursors havealso been found. An ion pair chromatographic methodwith ICP-MS detection for the separation of selenoaminoacid standards potentially present in real samples is given.The method allows separation of selenoamino acids includingsuch analytes as the cis-trans isomers of Se-1-propenyl-DL-selenocysteine. The method also providesthe capability of determining the presence of selenoxidesand possibly selenones, and tracking of other functionalitiesand reactions by selective derivatization. Alternatively,selenoamino acids are treated with ethylchloroformateto produce stable volatile derivatives which areamenable to GC separation with element specific atomicemission detection (GC-AED). Results of total seleniumdetermination and speciation of selenium enriched yeastbasednutritional supplements, selenium enriched alliumvegetables and bioremediation samples are presented.