INTERFERENCES OF OXIDE, HYDROXIDE AND CHLORIDE ANALYTE SPECIES IN THE DETERMINATION OF RARE-EARTH ELEMENTS IN GEOLOGICAL SAMPLES BY INDUCTIVELY-COUPLED PLASMA-MASS SPECTROMETRY

The analytical procedure for the determination of Ba and rare earth elements in rocks and minerals by ICP-MS is described. The yield of mono-oxide and hydroxide ions of Ba and rare earth elements, and chloride ions of Ba has been determined. A Microsoft Excel spreadsheet template has been written to calculate the expected peak intensities for all possible analyte species (M+, MO+, MOH+ and MCl+) as a function of the mass number. The degree of interferences of different analyte isotopes is estimated and interferent equivalent concentrations are given for elements, for which no isotope free from interferences is available. The method is applied to the analysis of the four Geo-Reference samples AC-E, GSP-1, G-2 and AGV-1; the analytical accuracy is better than +/- 10% for most of the elements when compared with recommended reference values.