Degradation process of graphite furnace estimated from atomic gas temperature of iron in graphite furnace atomic absorption spectrometry

GF-AAS has been employed for determining several trace impurities in metallic materials. The analytical precision in the continuous analysis tends to worsen due to thermal degradation of the graphite furnace at the atomization stage. Changes of the atomization condition along with increasing the number of measurements were investigated by monitoring the temporal variation in the atomic gas temperature of iron. In a working solution containing low-concentration of acid, the inner wall of the graphite furnace was gradually damaged and then the efficiency for the atomizing process was reduced. In a working solution containing sub-mol/L order of sulfuric acid, thinning or cracking of the graphite furnace progressed more rapidly and the function of it was greatly deteriorated.