The Direct Determination of Rare Earth Elements in Basaltic and Related Rocks using ICP‐MS: Testing the Efficiency of Microwave Oven Sample Decomposition Procedures

Abstract

Tests are described showing the results obtained for the determination of REE and the trace elements Rb, Y, Zr, Nb, Cs, Ba, Hf, Ta, Pb, Th and U with ICP‐MS methodology for nine basaltic reference materials, and thirteen basalts and amphibolites from the mafic‐ultramafic Niquelândia Complex, central Brazil. Sample decomposition for the reference materials was performed by microwave oven digestion (HF and HNO3, 100 mg of sample), and that for the Niquelândia samples also by Parr bomb treatment (5 days at 200°C, 40 mg of sample). Results for the reference materials were similar to published values, thus showing that the microwave technique can be used with confidence for basaltic rocks. No fluoride precipitates were observed in the microwave‐digested solutions. Total recovery of elements, including Zr and Hf, was obtained for the Niquelândia samples, with the exception of an amphibolite. For this latter sample, the Parr method achieved a total digestion, but not so the microwave decomposition; losses, however, were observed only for Zr and Hf, indicating difficulty in dissolving Zr‐bearing minerals by microwave acid attack.

The antecryst compositional influence on Cretaceous alkaline lamprophyre dykes, SE Brazil

“…A 100-mg aliquot was collected from each sample for etching via microwave. More details on the preparation can be found in Navarro et al (2008). Table 2 shows the modal analysis for each dyke and their different zones.…”

Simple and cost-effective methods for precise analysis of trace element abundances in geological materials with ICP-MS

“…Alkali fusion technique is effective to decompose resistant accessory minerals, but it causes high blank levels (i.e., flux impurities) and total dissolved solids (TDS). 5 Besides, its high Si content can also cause complex isobaric interferences [3], plus causing significant instrumental drift during analysis due to silicate salt deposits in the interiors of the sample/skimmer cones [9]. In this case, the high-pressure digestion (bomb) method remains the method of choice, especially when applied to coarse grained granitic and metamorphic rocks [10][11][12].…”

“…[4] and reference therein). A quantitative evaluation by Takei et al suggested that the formation of such insoluble phases can be avoided if sample size is small and if the digestion mixture is ensured not to be completely dry during evaporation [3,9].…”

Extensional Carboniferous magmatism at the western margin of Gondwana: Las Lozas valley, Catamarca, Argentina

“…After this, HF is eliminated as SiF 4 on a hot plate and the solution diluted in the ratio 1:2000 in 0.1 N HNO 3 . The reference curve was obtained preparing standard materials in the same way, for which the following reference samples were used: granites GA, GH, OU-3, and YG-1 and the basalt BE-N, besides a blank (for details, see Navarro et al, 2008).…”