An improved digestion technique for determination of platinum group elements in geological samples

This paper reports a modified digestion method for the determination of platinum group elements (PGEs) in geological samples. Samples are first digested by HF in a custom made 120 ml PTFE beaker on a hot plate to remove silicates. The dried residue is then digested with HF + HNO(3) at 190 degrees C for about 48 h after the beaker is sealed in a stainless steel pressure bomb. Although only HF + HNO(3) are used for sample digestion at relatively low temperature, ultramafic rocks with refractory minerals can be effectively decomposed by this method. Analytical results for CCRMP (CANMET, Ottawa, Canada) certified reference materials WGB-1 (gabbro), UMT-1 (ultramafic ore tailings), WPR-1 (peridotite) and WMS-1(Massive Sulphide), agree well with the certified values. The proposed method significantly simplifies the sample digestion procedures for PGE analysis compared to those used previously.