Comparative study to evaluate the effect of different acids on the determination of germanium by hydride generation inductively coupled plasma atomicemission spectrometry

A comparative study was performed to evaluate the effect of hydrochloric, t artaric, citric, oxalic, acetic and sulfosalicilic acids on the hydride gen eration of germanium at trace levels in a continuous flow system and induct ively coupled plasma atomic emission spectrometry (ICP-AES) detection. The operating conditions (chemical and physical parameters) and the concentrati ons of the acids studied have been optimized for the generation of GeH4 (ge rmane). Analytical figures of merit including detection limits, precisions and linear dynamic ranges are given for the six acids employed. The detecti on limits for Ge ranged between 0.096 and 0.295 mu g l(-1) depending on the acid used to generate germane. Compared to a conventional continuous nebul ization, the present coupling gives a sensitivity increase of a factor of a pproximately two orders of magnitude. The interferent effect of transition metals (Cd, Co, Cu, Cr, Mn, Ni, Zn), other hydride forming elements (As, Bi , Pb, Sb, Se, Sn, Te) and Hg upon Ge signal using the different acids studi ed were evaluated. Tartaric acid is the most suitable reaction medium, in t erms of efficiency in the hydride generation process and in reduction of in terferences. Besides, it allows for less strict control of the pH at which the generation of germane takes place. The proposed method was applied to t he determination of Ge in coal fly ashes. (C) 1998 Elsevier Science B.V. Al l rights reserved.