Trace element determination in alpine snow and ice by double focusing inductively coupled plasma mass spectrometry with microconcentric nebulization

Abstract

Double focusing inductively coupled plasma mass spectrometry (ICP-MS) has been applied to the direct, simultaneous determination of Ti, V, Cr, Mn, Fe, Co, Cu, Zn, Mo, Ag, Cd, Sb, Ba, Au, Pb, Bi and U in recent Alpine snow and old ice at the ng g ^–1 and pg g ^–1 level. Small amounts of sample (about 1 ml) were analysed using a microconcentric nebulizer. To avoid possible spectral interferences, measurements were carried out both in medium (m/Δm≈3400) and low (m/Δm≈300) resolution modes. Clean procedures were adopted both in the field and in the laboratory in order to reduce the possibility of sample contamination to a minimum. Concentration ranges of Alpine surface snow were (in pg g ^–1 ): Ti (8-106×10 ³ ), V (3-4601), Cr (3-2985), Mn (1-173×10 ³ ), Fe (67-1058×10 ³ ), Co (2-973), Cu (8-29.1×10 ³ ), Zn (2-6311), Mo (11-721), Ag (0.5-107), Cd (16-218), Sb (1.7-6173), Ba (9-36.5×10 ³ ), Pb (23-33.7×10 ³ ), Bi (0.1-116) and U (0.1-265). Much lower concentrations were detected in high altitude sites in the Alps. Measurement repeatability, in terms of RSD, ranged between 9 and 34%, depending on the element. The reliability of the analytical method was confirmed by analysis of a certified reference material (SLRS-3, riverine water) and by determination of Cd, Pb, Cu and Zn by ETAAS. For some of the elements investigated these results constitute the first available for recent Alpine snow and old ice.