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

Abstract

The determination of ultratraces of Au, Ir, Pd, Pt and Rh in silver nitrate by graphite furnace laser-induced fluorescence (GF–LIF) spectrometry is subject to strong interference by the formation of condensation. Two kinds of condensation are clearly identifiable: diatomic molecules (AgH, Ag₂) and condensed particles. In order to find the best analytical parameters for the determination of Au, Ir, Pd, Pt and Rh in silver nitrate by GF–LIF, a detailed study of the origin and spatio-temporal behaviour of these condensations was carried out. Solutions for matrix interference reduction are proposed, these include the use of neon as a purge gas, a preliminary evaporation of part of the matrix prior to atomization, and the use of a transverse heated atomizer.