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, selenate, selenocystine and selenomethionine was studied with a selenium-specific detector; electrothermal atomic absorption spectrometry. Three chromatographic modes were compared; two ion-pairing ones using either a cationic or an anionic reagent and ion-exchange. Separation parameters such as composition, pH and concentration of the mobile phase were investigated. The influence of chromatographic conditions on the sensitivity of the detector is studied. The ion-exchange method was determined 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.