Optimization of hydride generation atomic fluorescence spectrometry for the determination of trace amounts of germanium: emphasis on acidity and interferences Original Research Article

Three mol l−1 phosphoric acid or its mixture with another mineral acid (0–6 mol l−1) is recommended as a suitable medium for the generation of germanium hydride. In the presence of 3 mol l−1 phosphoric acid, the atomic fluorescence signal of germanium remains constant over a wide acidity range of the mineral acid (0–6 mol l−1) and the interferences from the transition metal ions are greatly reduced. The gas-phase interference from arsenic can be eliminated by on-line adsorption of the interferent by a HgCl2 mini-column. A (3σ) detection limit of 0.43 ng ml−1 Ge and a relative standard deviation of 2.5% for 200 ng ml−1 of Ge (n=11) were obtained. A convenient, rapid and selective method for the determination of traces of germanium in geological samples is proposed and the results obtained are in good agreement with the certified values.