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

The performance of a double-focusing inductively coupled plasma mass spectr ometer equipped with a microconcentric nebulizer was investigated for the d irect simultaneous determination of Rh, Pd, and Pt in less than 1 mt of mel ted snow and ice samples originating from remote sites. Ultraclean procedur es were adopted in the laboratories and during the pretreatment steps, to a void possible contamination problems. Spectroscopic and nonspectroscopic in terferences affecting the determination of Rh, Pd, and Pt were carefully co nsidered. Detection limits of 0.02, 0.08, and 0.008 pg g(-1) for Rh, Pd, an d 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 analy sis of samples coming from Greenland, Antarctica, and the Alps in order to assess the past natural background concentrations and to determine the pres ent level of these polluting substances. The extremely low detection limits allowed the direct analysis of all samples except for two Greenland ice ca re sections dating from 7260 and 7760 years ago for which a preconcentratio n 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). Th e lowest concentrations were measured in the enriched Greenland ancient ice samples.