Determination of germanium in different media by atomic absorption spectrometry with electrothermal atomization

Effectsof acids, alkalis or salts on the atomic absorption spectrometry (electrothermal atomization) of germanium are described. Most of the species tested interfere with the absorption. The mechanisms of the interferences were investigated by using tantalum-coated and standard graphite tubes. The results showed that positive interferences are due to inhibition of the reaction of germanium dioxide with carbon to form volatile GeO₃ and that suppressive interferences are due to physical occlusion effects. The addition of sodium hydroxide to the sample solution provides a very sensitive analysis (0.004 ppm for 1% absorption) for germanium without matrix interferences. This is probably due to the formation of stable Na₂GeO₃ during the ashing step in the presence of sodium hydroxide.