SILVER MATRIX EFFECTS ON GOLD ATOMIZATION IN A GRAPHITE-FURNACE INVESTIGATED BY 2-DIMENSIONAL LASER IMAGING WITH A GATED CHARGE-COUPLED-DEVICE CAMERA

A pulsed intensified charge coupled device (CCD) camera was used to make a diagnostic of perturbations, generated by increasing silver quantities, on the fluorescence signal of small amounts of gold. Using both absorption and laser-induced fluorescence (LIF) spectroscopy, pictures of the furnace, probed with a pulsed laser tuned on a gold transition, were recorded during the atomization step. Spectra of the atomic and molecular fluorescence generated by the laser were recorded using classical electrothermal atomization LIF. These data enabled the mapping of the atomic and molecular species distribution in the furnace, and the identification of the chemical nature of these molecules. No pronounced changes were observed in the gold atoms distribution when about 100-200 mu g of silver were atomized, relative to atomization of gold in a pure water matris. For the silver matrix (approximate to 1 mg), important silver condensations were formed and the distribution of gold atoms were strongly modified.