SPECIATION OF D,L-SELENOMETHIONINE ENANTIOMERS ON A BETA-CYCLODEXTRINCOLUMN WITH FLUOROMETRIC AND ONLINE HYDRIDE GENERATION INDUCTIVELY-COUPLED PLASMA-MASS SPECTROMETRIC DETECTION

O-Phtharaldehyde (OPA) and 2,3-naphthalenedicarboxaldehyde (NDA) were investigated as pre-column derivatizating reagents in order to achieve the chiral separation of D,L-selenomethioninn enantiomers on a beta-c yclodextrin column using fluorimetric detection. Good resolution was a chieved between the NDA-derivatized enantiomers with a mobile phase of 60% v/v methanol-0.5% triethylammonium acetate (pH 5). The sensitivit y and selectivity of the fluorimetric detection of the derivatives wer e compared with selenium-specific detection by on-line microwave-HG-IC P-MS. Limits of detection of 2.7 and 70 mu g l(-1), respectively, were obtained, This sensitivity allowed the detection of small amounts (0. 1-1%) of D-selenomethionine in commercially pure L-selenomethionine sa mples using both detectors. The HG-ICP-MS detector proved to be superi or in terms of selectivity to selenium, as demonstrated by preliminary results obtained for D,L-selenomethionine determination in complex sa mples (selenium-enriched yeast), Selenomethionine could not be determi ned in such samples by fluorimetric detection owing to the presence of many other interfering amino acids at concentrations higher than that of selenomethionine which react with OPA and NDA.