Determination of Rh, Pd, and Pt in polar and alpine snow and ice by double focusing ICPMS with microconcentric nebulization

The performance of a double-focusing inductively coupled plasma mass spectrometer equipped with a microconcentric nebulizer was investigated for the direct simultaneous determination of Rh, Pd, and Pt in less than 1 mt of melted snow and ice samples originating from remote sites. Ultraclean procedures were adopted in the laboratories and during the pretreatment steps, to avoid possible contamination problems. Spectroscopic and nonspectroscopic interferences affecting the determination of Rh, Pd, and Pt were carefully considered. Detection limits of 0.02, 0.08, and 0.008 pg g(-1) for Rh, Pd, and Pt, respectively, were obtained using the following isotopes: Rh-103, Pd-106, and Pt-195. Repeatability of measurements, as RSD, was 27, 28, and 29%, for Ph, Pd, and Pt, respectively. The new method was applied to the analysis of samples coming from Greenland, Antarctica, and the Alps in order to assess the past natural background concentrations and to determine the present level of these polluting substances. The extremely low detection limits allowed the direct analysis of all samples except for two Greenland ice care sections dating from 7260 and 7760 years ago for which a preconcentration step was necessary. Concentration ranges for all snow samples were (in pg g(-1)) as follows: Rh(0.0005-0.39), Pd (0.01-16.9), and Pt (0.008-2.7). The lowest concentrations were measured in the enriched Greenland ancient ice samples.