Determination of Ultra-Trace Au, Pt and Pd in Topsoil Samples by Foam Plastics Enrichment-Inductively Coupled Plasma-Mass Spectrometry

The samples were dissolved by aqua regia, reduced by SnCl₂ and absorbed by the foam plastics. The ultra-trace Au, Pt and Pd in topsoil samples had been simultaneously determined by inductively coupled plasma-mass spectrometry (ICP-MS) with Re as internal standard. The adsorption efficiency was stable under the conditions of 15% HCl, 45 g/L SnCl₂ and absorption time of 30 minutes at 25℃. The detection limits of Au, Pt and Pd were 0.21 ng/g, 0.18 ng/g and 0.16 ng/g, respectively. The recovery coefficients of Au, Pt and Pd were 93.3%-97.6%, 92.5%-102.5% and 91.0%-98.4%, respectively. This method was verified by the analysis of the national standard samples with accurate and reliable results. This method has the advantages of simple operation, rapid analysis, wide linear range and reproducibility.