Simultaneous determination of ruthenium, palladium, iridium, and platinum at ultratrace levels by isotope dilution inductively coupled plasma mass spectrometry in geological samples

Inductively coupled plasma mass spectrometry employing isotope dilution quantification (ID-ICPMS) has been applied to determine trace levels of Ru, Pd, Lr, and Pt in geological materials, Accuracy, precision, and reproducibility are better than those obtained by other ICPMS calibration methods, For this purpose, it is important to achieve isotopic equilibrium by use of a microwave oven, Due to the trace concentration of these elements in geological samples, a method for separation of these elements from the matrix has been developed, taking advantage of formation of strong anionic complexes of Pd, Pt, Ru, and Ir in a hydrochloric acid medium, Since doubly charged complexes, MCl(6)(2-), are strongly sorbed by the anion exchange resin, whereas triply charged complexes, MCl(6)(3-), are weakly bound, various oxidizing agents were examined in this study to convert the lower oxidation states of these elements to their higher oxidation states, Systematic studies on retention and elution of these elements were carried out with various mineral acids, optimum conditions for which were established, Recoveries obtained were 90 +/- 10% for all four elements, Reproducibility was subsequently checked with synthetic samples, The method has been applied to the determination of PGEs in reference materials WPR-1 and WMS-1, a meteorite sample (Orgueil), and cretaceous-tertiary (K-T) boundary samples from Stevns Klint, Denmark.