New ICP-MS results for trace elements in five iron-formation reference materials

Abstract

Iron formations (IFs) typically contain low mass fractions of most trace elements, including the rare earth elements (REE), and few publications describe analytical methods dedicated to this matrix. In this study, we used bomb and table-top acid dissolution procedures and ICP-MS to determine the mass fractions of trace elements in IF reference materials FER-1, FER-2, FER-3, FER-4 and IF-G. The full digestion of the IF samples with the bomb procedure required the addition of a small amount of water together with the acids. The results obtained by this method mostly agreed statistically with published values. The most remarkable exception was the higher values obtained for the heavy REE in FER-3. The recoveries of the REE obtained with the table-top procedure were slightly higher than those of the bomb digestion, except for the values of the heavy REE in FER-3 and FER-4, which were up to 30% lower than published values. Sintering of the samples with sodium peroxide was performed to determine the REE, but the results tended to be lower than those derived following acid digestion. On the whole, the recoveries showed dependence on the conditions of digestion, but subtle differences in trace mineral composition between samples also exerted influence on the analytical results for trace elements.

Iron formations (IFs) typically contain low mass fractions of most trace elements, including the rare earth elements (REE), and few publications describe analytical methods dedicated to this matrix. In this study, we used bomb and table-top acid dissoluti