Analytical Sciences

Abstract − Analytical Sciences, 26(8), 867 (2010).

Application of a Dynamic Reaction Cell (DRC) ICP-MS in Chromium and Iron Determinations in Rock, Soil and Terrestrial Water Samples
Yasumasa OGAWA, Shin-ichi YAMASAKI, and Noriyoshi TSUCHIYA
Graduate School of Environmental Studies, Tohoku University, 6-6-20 Aoba, Aoba, Aramaki, Sendai 980-8579, Japan
Despite environmental and geochemical interests, Cr and Fe have been left beyond the reach of determinations by ICP-MS due to severe interferences originating from Ar. The applicability of a dynamic reaction cell (DRC)-ICP-MS has been examined for determinations in environmental and geochemical samples. The reaction with NH3 in the DRC system provides an eligible technique to determine Cr, because of a greater improvement in the signal/noise (S/N) ratio due to an effective elimination of interferences arising from Ar (ArC, ArN and ArO), and makes it possible to analyze Cr even at sub-μg L−1 levels. As compared to non-DRC mode analyses, the DRC technique using m/z 56 appeared to be preferable for Fe determination in most terrestrial waters because of effective suppression of 40Ar16O+. In addition, the effects of cluster ions, such as 39K14N1H3+ and 40Ca14N1H2+, on Fe determination were also negligibly small. Measurements using 54Fe by the DRC mode are also advantageous for Ca-rich samples, such as limestone and dolomite.