Major- and trace-element analysis of sulfide ores by laser-ablation ICP-MS, solution ICP-MS, and XRF: New data on international reference materials

International reference materials representing a diverse suite of sulfide ores and related lithologies have been analyzed for major and trace element concentrations by XRF, solution ICP-MS, and laser-ablation ICP-MS (LA-ICP-MS) after fusion of the sample to a lithium borate glass. Reference materials analyzed for this study include a wide variety of bulk compositions, including ores of Pb-Zn sulfides, Fe sulfides, Cu-Mo sulfides, and silicate matrices. Concentrations of 33 elements were determined, including lithophile and chalcophile elements of particular interest to economic geochemistry and ore deposit studies. The results of LA-ICP-MS analyses were calibrated using a fused glass standard prepared specifically for the analysis of sulfides. Accuracy of the LA-ICP-MS technique is established by comparison with results obtained by the other methods for abundance variations over several orders of magnitude. Replicate analyses demonstrate a precision of 2-8% (1σ RSD) for the LA-ICP-MS data at rock-equivalent concentrations >1 ppm. Matrix effects were not a significant problem at the scale of compositional variation represented by these samples, and no significant differences in the results were produced with the laser operating in either fixed-spot or line-scan mode. LA-ICP-MS analysis of fused glasses effectively overcomes problems related to insoluble phases such as cassiterite that are resistant to acid dissolution. Whole-rock analysis of sulfide ores by XRF and LA-ICP-MS provides a fast and convenient approach for determinations of major-and trace-element concentrations in a variety of ores and related materials without the need for wet-chemical dissolutions.