The platinum group elements (PGEs) Pt, Pd, Ru, Rh, Os, and Ir are found in nature heterogeneously distributed at ultratrace levels. They are, however, of major economic importance, being used as catalysts in the petroleum and chemical industries, as a raw
material in the manufacture of electronic components and jewellery, and as a form of investment. Levels of a few þgþg-1 may be economic to recover, and consequently determinations of sub-ngþg-1 levels are required for geological studies. Recent developments in analytical instrumentation, such as
graphite furnace-atomic absorption spectroscopy, inductively coupled plasma-atomic emission spectroscopy (ICP-AES) and ICP-mass spectroscopy (ICP-MS), have encouraged a reassessment of methods for PGE determination. To analyze at the ultratrace levels present in natural materials, however, usually
requires a preconcentration and/or separation step before final analysis. Traditionally, fire assay has been used to concentrate PGEs in ores, collecting the noble metals in a lead, copper, or nickel sulphide button. This technique requires specialized equipment, large amounts of analytical
reagents, and special procedures to avoid loss of volatile Os and Ru compounds. Additionally, analytical results are highly dependent on the assay conditions. Tellurium collection has also been used to separate and collect the PGEs, although this procedure is lengthy and isotope dilution is
necessary to correct for incomplete co-precipitation. An alternative to Te collection is ion-exchange chromatography. The PGEs readily form anionic chloro-complexes enabling two approaches to ion exchange: (1) an anionic resin can be used and PGE species trapped on the resin, to be subsequently
eluted and analyzed; or (2) a cationic resin can be used to remove the matrix elements, thereby allowing the analysis of concentrated solutions of PGEs. This paper will present results from our research programme which aims to develop simplified procedures for the determination of the PGEs. A
two-step dissolution will be discussed which combines a quick acid attack in sealed microwave vessels, followed by lithium borate fusion of the refractory minerals. Results for two types of ion-exchange resins will be presented (anionic resin, Dowex 1-X8, and cationic resin, Dowex 50W-X8), based on
data obtained by ICP-AES and ICP-MS. Procedures will be evaluated using a range of PGE certified reference materials from South Africa (SARM-7) and Canada (PTA-1, PTC-1, PTM-1, and SU-1a).