Direct determination of germanium in botanical samples by graphite furnace atomic absorption spectrometry with palladium-zirconium as chemical modifier.

A method has been described for the direct determination of trace levels of germanium by graphite furnace atomic absorption spectrometry (GFAAS) using chemical matrix modification technique. The stabilization and the pyrolysis temperatures for germanium were investigated with various chemical modifiers including palladium, palladium-magnesium, palladium-strontium and palladium-zirconium. The highest pyrolysis temperature and highest integrated absorbance were obtained using palladium-zirconium modifier, and the severe matrix interference from sulfate can be eliminated. The characteristic mass and absolute detection limit (3sigma) of germanium were found to be 16 and 12 pg, respectively. The proposed method was applied to the determination of trace levels of germanium in botanical samples with a recovery range of 92-106%. The hydride generation atomic fluorescence spectrometric (HGAFS) method was employed to analyze the samples and the results agree well with those obtained by GFAAS. The contents of germanium in standard reference materials were determined and the results were in good agreement with the reference values.