CHARACTERIZATION AND REDUCTION OF SILVER MATRIX INDUCED EFFECTS IN THE DETERMINATION OF GOLD, IRIDIUM, PALLADIUM, PLATINUM AND RHODIUM BY GRAPHITE-FURNACE LASER-INDUCED FLUORESCENCE SPECTROMETRY

The determination of ultratraces of Au, Ir, Pd, Pt and Ph in silver ni trate by graphite furnace laser-induced fluorescence (GF-LIF) spectrom etry is subject to strong interference by the formation of condensatio n, Two kinds of condensation are clearly identifiable: diatomic molecu les (AgH, Ag-2) and condensed particles, In order to find the best ana lytical parameters for the determination of Au, Ir, Pd, Pt and Ph in s ilver nitrate by GF-LIF, a detailed study of the origin and spatio-tem poral behaviour of these condensations was carried out, Solutions for matrix interference reduction are proposed, these include the use of n eon as a purge gas, a preliminary evaporation of part of the matrix pr ior to atomization, and the use of a transverse heated atomizer.