ADAPTATION OF THE FILTER FURNACE ATOMIZER FOR ATOMIC-ABSORPTION DETERMINATION OF LESS VOLATILE METALS

The filter furnace atomizer (FF), which has already been proposed for electrothermal atomic absorption spectrometry, provides enhanced sensi tivity, a reduction of interferences and reduced analytical time. The main disadvantage of the FF is the rapid destruction of the filter at the atomization temperatures of less volatile or carbide-forming eleme nts, In the current work, radiative heat exchange between the componen ts of the FF was considered to be predominant at high temperature. The thermal behaviour of the FF was therefore examined at fast heating ra te as a function of its configuration, the type of graphite used for t he components, and the voltage applied, The optimal combination of ele ctrical resistivity, relative dimensions and mass of the FF components was determined for the HGA-500 atomizer. The improvements resulted in a significantly increased lifetime of the FF in the multiple determin ation of Al, As, Co, Cr, Cu and Ni. The filter withstood 150 firings a t 2600 degrees C (hold time 15 s) in the determination of Cr. The theo retical approach can be applied to different types of atomizers. (C) 1 997 Elsevier Science B.V.