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

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 ate greatly reduced. The gas-phase interference from arsenic can be eliminated by on-line adsorption of the interferent by a HgCl2 mini-column. A (3 sigma) 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. (C) 1998 Elsevier Science B.V. All rights reserved.