A solid-sampling system for a transversely heated graphite furnace and its application to trace element analysis of high-purity tantalum powders by atomic absorption spectrometry

An electrothermal atomic absorption spectrometer with transversely heated graphite tube and a solid-sampling system was applied to the direct analysis of high-purity tantalum powders. Sample introduction was based on the 'boat' technique. The optimized sample platform was short enough to fit completely into the tube and its semicylindrical cross-section allowed the introduction of sample volumes up to 30 mu l. The platform manipulator constructed for the handling of these boats provided high mechanical precision, low risk of contamination and rapid operation. The maximum applicable tantalum sample amount was 60 mg per atomization. For the analyte elements Cu, Fe, K, Mg, Mn, Na and Zn, the method provided limits of detection of 0.15, 4.0, 0.1, 1.3, 0.12, 0.16 and 0.02 ng g(-1), respectively. Calibration was performed using aqueous standard solutions, and the results agreed satisfactorily with those obtained by ETAAS involving sample digestion. (C) 1998 Elsevier Science B.V. All rights reserved.