APPLICATION OF PALLADIUM-PLATING AND RHODIUM-PLATING OF THE GRAPHITE-FURNACE IN ELECTROTHERMAL ATOMIC-ABSORPTION SPECTROMETRY

Palladium- and Rh-plating of the graphite furnace has been evaluated a s a method of introducing the metallic form of Pd and Rh for chemical modification in electrothermal atomic absorption spectrometry, It is s hown that by electroplating Pd and Rh onto the inner surface of the tu be, the pre-treated graphite surface may resemble the behaviour of the corresponding modifier, The resulting metallic layer is very effectiv e in inhibiting the loss of volatile elements (e.g., As and Se), as we ll as reducing the influence of oxide and carbide formation (e.g., Si) , The advantage of the proposed procedure of introduction of a solid c hemical modifier is that the pre-treated tubes exhibit an extended ana lytical lifetime for the determination of As and Se, up to 80 and 160 brings in the presence of Pd and Rh, respectively, In the case of Si t he Rh-plated graphite tube could last for about 100 firings.