Probe design considerations in graphite probe electrothermal atomisation atomic absorption spectrometry

Abstract

The development of a new design of graphite probe suitable for use in a front entry automatic graphite probe system for graphite furnace atomic absorption spectrometry is described. The optimum design consisted of a thick stem (1.5 mm) for increased mechanical strength, a thin probe head (0.3 mm) for fast heating rates and a thin ridge to stop solutions spreading down the probe stem and out of the graphite tube during the drying phase of the analytical cycle. Although sensitivity was reduced slightly with the use of the probe system the range of signals free from vapour phase interferences was greatly extended when compared with tube-wall atomisation. Up to 1.0%m/V MgCl2 could be tolerated with the probe system whereas a 60–70% depression of the analytical signal was observed with tube-wall atomisation.