Comparison of Two Methods for Determination of Rhenium and Platinum-Group Elements in Meteorites Using On-Line and Off-Line Matrix Separation Modes

Abstract

The abundances of rhenium (Re) and platinum-group elements (PGE) and their variation patterns provide crucial insights into the evolution of planetary bodies, including the Moon. The objective of this study is to evaluate the applicability of the Carius tube and HPA-S digestion methods, as well as online and offline separation and detection techniques, for determining the mass fractions of Re and PGE in meteorites. The findings demonstrated that HPA-S is capable of completely dissolving refractory minerals and is a more effective dissolution method for meteorite samples than the Carius tube approach. The combination with cation exchange resin and online matrix separation allows for complete control over interfering elements, making it particularly promising for analysing extraterrestrial samples with high Zr/Pd ratios, such as Martian meteorites and lunar rocks. However, it was observed that PEEK tubing adsorbs Pd and Pt ions, resulting in significantly reduced recoveries of these elements during chromatographic separation. Therefore, the use of PEEK during chromatographic separation is not recommended. The optimised measurement procedure was validated using PGE reference materials OKUM, GPt-3 and UMT-1, and the resulting measurement values were found to agree with the literature values.