Examination of the effect of furnace design on sensitivity in graphite furnace atomic absorption spectrometry

Abstract

The performances of three small laboratory-made graphite furnaces, designed for use in electrothermal atomisation atomic absorption spectrometry (ETA-AAS) with a longitudinal magnetic-field Zeeman-effect background-correction system and operated without a sample drying stage, have been examined and compared with those of conventional tubular furnaces. The performance of a double-pass optical system was also examined. The purpose of this study was to obtain the lowest detection limit for copper with respect to the analyte concentration in the sample and also to minimise the cycle time per sample. The performances of the furnaces were related to a simple theoretical model of atomisation. It was found that the sensitivities of the commercial systems were an order of magnitude better than the laboratory-made furnaces but their minimum cycle times were twice as long, i.e., 1 min compared with 30 s. The use of a double-pass optical system led to a doubling of the sensitivity.