DETERMINATION OF BASE METALS IN GOLD BULLION BY FLOW-INJECTION INDUCTIVELY-COUPLED PLASMA-ATOMIC EMISSION-SPECTROMETRY

Gold bullion (unrefined gold) can be dissolved in concentrated nitric and hydrochloric acids. In order to prevent silver chloride precipitation, sample dilution was done with concentrated hydrochloric acid. This enables the determination of base metals (Cu, Fe, Ni, Pb, and Zn) in gold bullion by flow injection ICP-AES. Sample introduction through a single line flow injection manifold minimizes the amount of concentrated acid introduced directly into the spectrometer. Calibration standards were made from pure metals dissolved in the same manner as the samples. The accuracy of the method was assessed by recovery experiments (97-108%). Method detection limits were estimated to be 0.02%, 0.004% 0.08%, 0.01%, and 0.02% (% wt/wt) for Cu, Fe, Ni, Pb, and Zn, respectively. The method of analysis was useful for analytes, Fe, Ni, Pb, and Zn, ranging in concentration from 0-1.5% (wt/wt) and for Cu which ranged from 0-13%.