ELEMENTAL SPECIATION BY ANION-EXCHANGE AND SIZE-EXCLUSION CHROMATOGRAPHY WITH DETECTION BY INDUCTIVELY-COUPLED PLASMA-MASS SPECTROMETRY WITH DIRECT-INJECTION NEBULIZATION

A direct injection nebulizer (DIN) is used with packed microcolumns fo r anion chromatography (AC) and size exclusion chromatography (SEC). T wo Se species (SeO32- and SeO42-) are separated by AC with detection l imits of 15 pg of Se. The isotope ratio Se-74/Se-78 can be measured wi th a relative standard deviation of 0.5 % on 25 ng of each Se species during the actual chromatographic separation. Proteins in human serum are separated by SEC without sample pretreatment. The metals present i n each molecular weight fraction are determined by ICP-MS with detecti on limits of 0.5-3 pg of metal. These absolute detection limits are 1- 2 orders of magnitude better than those obtained with conventional neb ulizers.