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).
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.