SLURRY SAMPLING ELECTROTHERMAL ATOMIC-ABSORPTION SPECTROMETRY FOR THEANALYSIS OF GRAPHITE POWDERS

A direct method for the determination of Al, Ca, Cr, Cu, Fe, K, Mg, Na , Ni, Pb, Si, Sn and Zn in graphite powder using slurry sampling elect rothermal atomic absorption spectrometry is described. The influence o f the refractory matrix on the atomisation behaviour of the analyte el ements is examined. The method is optimised in respect of slurry prepa ration, pyrolysis and atomisation parameters. Except for Mg and Si, no chemical modification is necessary. The limits of detection are in th e range 8-30 ng g(-1) for Ca, Cr, Cu, K, Mg, Na and Zn, between 50 and 200 ng g(-1) for Al, Fe, Ni, Pb and Sn, and for Si a detection limit of 800 ng g(-1) is achieved. By comparison of the results with those o btained by instrumental neutron activation analysis and by various oth er methods used in a collaborative study, it is shown that the propose d method provides good accuracy.