Rapid determination of Ru, Rh, Pd, Ir, and Pt in rock samples using ICP-MS following microwave digestion

This study introduces a novel rapid and efficient analytical approach for the determination of PGEs, excluding Os, in rock samples by ICP-MS. This approach combines effective matrix removal in silicate rock samples through the formation of insoluble fluorides during microwave-assisted digestion and the volatilization of silicon as SiF₄ with the capability of ICP-MS to quantify target isotopes at very low signal intensities (10-100 cps) using optimized acquisition parameters. Moreover, the ability to perform ICP-MS measurements at such low signal intensities also enables matrix reduction in other sample types, such as ores, through simple dilution while maintaining sufficient analytical sensitivity. Since proposed strategy employs fast microwave dissolution of PGEs together with their reliable and accurate determination, without the need for complex and time-consuming matrix-separation procedures such as ion-exchange chromatography or tellurium co-precipitation, the analytical workflow is significantly simplified, and the overall analysis time is reduced several-fold compared with conventional methods. At the same time, detection and quantitation limits are below 0.1 and 0.5 ng/g, respectively, for all analytes except Pd, for which the corresponding limits are 0.18 and 0.9 ng/g, enabling the determination of PGEs in variety rock types. The new method was verified using six rocks certified reference materials (CRMs) MUH-1 (harzburgite), NCS-DC73354/GBW07290 (peridotite), OKUM (komatiite), and UMT-1 (ultramafic ore tailings), WMS-1a (massive sulfide) and NCS-DC73356/GBW07292 (chromitite). The results obtained showed excellent agreement with both certified values and previously published data, with the vast majority of measurements falling within stated uncertainties or within ±10% of certified values.