PALLADIUM AS A MATRIX MODIFIER IN GRAPHITE-FURNACE ATOMIC-ABSORPTION SPECTROMETRY OF GROUP IIIB-VIB ELEMENTS

The performances of palladium as a matrix modifier for group IIIB - VIB elements in graphite-furnace atomic absorption spectrometry were compared to those of other modifiers hitherto reported. The application of palladium and mixed modifiers containing palladium to biological, mineral sediment or natural water samples is summarized. The addition of palladium generally makes a higher thermal pretreatment temperature possible without any sensitivity loss, thus reducing the interferences of coexisting materials. Mass spectrometry connected to graphite-furnace atomic absorption spectrometry enabled real-time observations of the vaporized species in the furnace and revealed the vaporization and atomization process of arsenic and selenium in the presence of palladium. Both elements form compounds Pd(n)M(m)O(l) (M=As or Se), which are then decomposed to PdM and finally to atomic vapor of M.