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 hea ted graphite tube and a solid-sampling system was applied to the direc t analysis of high-purity tantalum powders. Sample introduction was ba sed on the 'boat' technique. The optimized sample platform was short e nough to fit completely into the tube and its semicylindrical cross-se ction allowed the introduction of sample volumes up to 30 mu l. The pl atform manipulator constructed for the handling of these boats provide d high mechanical precision, low risk of contamination and rapid opera tion. The maximum applicable tantalum sample amount was 60 mg per atom ization. For the analyte elements Cu, Fe, K, Mg, Mn, Na and Zn, the me thod provided limits of detection of 0.15, 4.0, 0.1, 1.3, 0.12, 0.16 a nd 0.02 ng g(-1), respectively. Calibration was performed using aqueou s standard solutions, and the results agreed satisfactorily with those obtained by ETAAS involving sample digestion. (C) 1998 Elsevier Scien ce B.V. All rights reserved.