Analysis of geologic reference materials for REE and HFSE by inductively coupled plasma-mass spectrometry (ICP-MS)

A variant of the ICP-MS technique was developed for the analysis of geological materials for REE and HFSE (Zr, Nb, Hf, and Ta) and is illustrated by analyzing geological reference materials (GRM) of various composition. The chemical preparation of the samples, including their sintering/fusing with highly purified Li metaborate and the stabilization of the solution, ensures the complete transfer of the elements to be analyzed into solution. The use of an ELEMENT high-sensitivity mass spectrometer with an U-5000AT+ ultrasonic nebulizer made it possible to improve the detection limits of REE and HFSE. A combination of an external calibration with internal standard for the calculation of the concentrations allowed us to take into account the effect of the matrix and variations in the plasma parameters on the analytical signal. The accuracy of the method is illustrated by the comparison of the results obtained on the most reliably certified GRM with the values assumed for them. The relative standard deviation of the analysis amounts to 2–5% on average, depending on the concentrations.