SEPARATION AND DETERMINATION OF GOLD FROM TRON RICH MATRICES BY AN OFF ON-LINE PRECONCENTRATION SYSTEM COUPLED TO ICP-AES/

A preconcentration/separation method has been developed for the off/on -line determination by ICP-AES of gold in complex matrices, containing iron and manganese which cause severe spectral interferences on the t wo most sensitive Au-lines. The available automated preconcentration a pparatus was modified using as absorbent the highly selective, for pre cious metals, chelating anion exchanger SRAFION NMRR. From the elution of this resin with 5% thiourea a nearly quantitative recovery of gold and its separation from iron, existing in percent range in the matrix , and from manganese was obtained. The validity of the developed metho d was tested by the determination of gold in standard reference materi als from BCR, such as sewage sludge of domestic and mainly industrial origin and in a calcareous loam soil. The preconcentration procedure w as synchronized with the ICP operating parameters in order to get an o ptimised on-line coupling of these two systems. The described process has been successfully applied to the determination of low gold content s in dissolved iron rich sediments using for the gold prospection.