OPTIMIZATION OF THE DETERMINATION OF INORGANIC AND ORGANIC SELENIUM SPECIES USING HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY - ELECTROTHERMAL ATOMIC-ABSORPTION SPECTROMETRY

The liquid chromatographic simultaneous separation of selenite, selena te, selenocystine and selenomethionine was studied with a selenium-spe cific detector; electrothermal atomic absorption spectrometry. Three c hromatographic modes were compared; two ion-pairing ones using either a cationic or an anionic reagent and ion-exchange. Separation paramete rs such as composition, pH and concentration of the mobile phase were investigated. The influence of chromatographic conditions on the sensi tivity of the detector is studied. The ion-exchange method was determi ned to give the best results, with detection limits ranging from 8 to 17 mu g l(-1) within a 30 min separation time. An application of this method to the analysis of seleno compounds present in a selenium-rich yeast after enzymic hydrolysis extraction is presented.