Major- And Trace-Element Analysis of Sulfide Ores by Laser-Ablation Icp Ms, Solution Icp Ms, and Xrf: New Data on International Reference Materials

Abstract

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% (1 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 fixedspot 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.

Trace Element Analysis of Minerals in Magmatic-Hydrothermal Ores by Laser Ablation Inductively-Coupled Plasma Mass Spectrometry: Approaches and Opportunities

“…Use of appropriate matrix-matched reference standards is critical to enable correction for laser-induced fractionation during ablation, and thus reliable and reproducible quantitative outcomes (e.g., [25][26][27][28][29][30][31][32]). Table 1 lists reference materials commonly employed for LA-ICP-MS trace element analysis, matrices for which they have been applied, and key references regarding their suitability.…”

Applications of LA-ICP-MS in the elemental analyses of geological samples

“…With the exception of the noble metal elements, the trace elements in sulfides could be calibrated against pressedpowder pellets of sulfide (e.g. MASS-1 or MASS-3) [153], glasses of sulfide fused with a lithium borate flux [68,154,155], silicate reference glasses [156,157] or multi-element standard solutions [158]. Košler et al [111] found that a small amount of oxygen released from the sample during the laser ablation process can also affect the elemental fractionation.…”

Analytical Methods for Sulfur Determination in Glasses, Rocks, Minerals and Fluid Inclusions

“…Instead it has been employed for analyses of sulfur in sulfide minerals, where the S + / O 2 + ratio is very high, and in particular where sulfur was measured only as the internal standard element for ablation-yield corrections (e.g., Ballhaus and Sylvester 2000;Cabri et al 2003;Wohlgemuth-Ueberwasser et al 2007). Norman et al (2003) used this method to measure sulfur concentrations of 1.7 to 37 wt% in sulfide ore reference materials prepared with lithium borate as fused glass discs, applying 57 Fe as the internal standard isotope, on 100-μm diameter ablation spots. They reported detection limits for sulfur of 0.55 wt%, precisions of better than Notes: The isotopic mass data are from Audi et al (2003).…”