Determination of germanium by graphite-furnace atomic-absorption spectrometry

The premature loss of germanium as volatile GeO results in low sensitivity and poor reproducibility in the determination of germanium by graphite-furnace atomic-absorption spectrometry. This interference can be eliminated by suppressing the premature reduction of GeO(2) to GeO during the ashing step, and dissociating the germanium oxides into the atoms simultaneously with their vaporization during the atomization step. The premature reduction of GeO(2) to GeO has been successfully prevented by several approaches: (1) diminishing the reducing activity of the graphite furnace by (a) oxidizing the graphite surface and intercalating oxygen into the graphite lattice with oxidizing acids, such as nitric or perchloric, in the sample solution, or (b) using a tantalum-treated graphite furnace; (2) keeping the analyte as germanium (IV) by addition of sodium or potassium hydroxide to the sample solutions.