Determination of platinum-group elements in rocks by ICP-MS with external calibration after cation exchange separation of matrix elements by KU-2-8 resin

Abstract

The analytical technique to determine platinum-group elements ( PGEs ) Ru, Rh, Pd, Ir, Pt and Re in the geological samples within 0.1 ng/g – 10 μg/g range and Os on ng/g level in the ultramafic rocks by inductively coupled plasma mass-spectrometry with external calibration and without chemical removal of main interferences of Zr and Hf was proposed. The samples were prepared after their burning by acid decomposition in the open vessels, melting the insoluble residue with NH 4 F and with a subsequent cation exchange separation of PGEs from matrix elements by KU-2-8 resin (Russia). The measurements have been carried out using the high resolution mass-spectrometer Element 2 (Germany). The accuracy of the technique on μg/g level has been verified with reference materials: pyrrhotite ore RP-1 (Russia) and sulfide copper-nickel ore Zh-3 (Russia). In addition, the accuracy of the trace level (ng/g) has been verified by comparison of the results obtained in this study with those reported in the literature for international sample of comparison OPY-1, developed by the International Association of Geoanalysts (IAG). The procedural blanks are 0.000 n ng/ml for Os, 0.00 n ng/ml for Ru, Rh, Re, Ir and 0.0 n ng/ml for Pt and Pd. The detection limits were estimated by taking into account the blanks and their standard deviations (sample mass 1 g, volume 50 ml) and were 0.02 ng/g for Os, 0.07 ng/g for Re, 0.09 ng/g for Rh and Ir, 0.13 ng/g for Ru, 1.0 ng/g for Pt and 1.4 ng/g for Pd respectively. The content of Re was determined in the reference materials RP-1 and Zh-3, and in the sample of comparison OPY-1. Key words : platinum-group elements and Re, inductively coupled plasma mass-spectrometry, chromatographic separation, RP-1, Zh-3, OPY-1, external calibration. (Russian) DOI: http://dx.doi.org/10.15826/analitika.2016.20.3.003 V.I. Men’shikov, V.N. Vlasova, V.I. Lozhkin, Iu.V. Sokol’nikova Vinogradov Institute of Geochemistry, Siberian Branch of the Russian Academy of Sciences (IGC SB RAS) Favorsky ul., 1A, Irkutsk, 664033, Russian Federation