HYDRIDE GENERATION INDUCTIVELY-COUPLED PLASMA-ATOMIC EMISSION-SPECTROMETRY FOR THE DETERMINATION OF GERMANIUM IN IRON-METEORITES

A simple, rapid, and sensitive method is described for the determination of trace concentrations of germanium by inductively coupled plasma atomic emission spectrometry (ICP-AES) with hydride generation. The operating conditions have been optimized for the continuous generation of germanium hydride (GeH4, germane) and its determination by ICP-AES. The effects of several inorganic and organic acids and interelement interference effects have been examined. Phosphoric acid (0.02 M) is the most suitable reaction medium for germane generation. Compared with a conventional solution nebulization the present system can give rise to a sensitivity increase of a factor of approximately three orders of magnitude. The method has a detection limit of 0.063 ng/ml of germanium, and the linear dynamic range spans nearly five orders of magnitude from 0.1 ng/ml of germanium. The precision values at 5 and 500 ng/ml of germanium are 1.4 and 1.2% relative standard deviation (n = 10), respectively. Iron meteorites have been digested in a microwave oven equipped with Teflon-perfluoroalkoxy digestion vessels. Most of the interference effects of matrix elements in the samples can be minimized by the addition of either thiourea or 1,10-phenanthroline, but the method of standard additions is recommended for accurate determinations. The present method is applied to the determination of germanium in several iron meteorites. The results are in good agreement with the reported values. (C) 1994 Academic Press, Inc.