Determination of Platinum, Palladium and Gold in Geological Samples by Bomb-inductively Coupled Plasma-Mass Spectrometry with Concentrate and Extraction by Mixed Adsorbent

Fire assay separation enrichment technology has been applied to precious metals analysis, however, its ingredients are complex, time-consuming, analysis costs are relatively high and blank controls are more difficult. A new method was set up such as the samples were dissolved with H₂O₂-HCl before Pt, Pd and Au were determined by Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). In 10% hydrochloric acid solution, LSC-400 mercapto resin and activated carbon were mixed as the adsorbent. Pt，Pd and Au in the sample solution were separated and enriched by using dynamic adsorption. Lu was selected as the internal standard element to eliminate non-spectral interference and spectrum interference along with tracers of ¹⁹⁵Pt, ¹⁹⁷Au and ¹⁰⁸Pd. The recovery rates of each element were more than 96.4%. The detection limits were 0.06 ng/g for Pt, 0.08 ng/g for Pd and 0.12 ng/g for Au. Compared with the detection limits, this established method was better than the fire assaying method and other separation and enrichment methods. The method has been applied to the determination of these elements in National Standard Materials for PGEs and results were in agreement with the certified values. The relative standard deviations (RSD, n=12) was less than 16.1%. The method is simple, low cost and greatly improves the speed of analysis，and effectively reduces the blanks of the chemical processing.