Accurate Quantification of H, Li, Be, B, F, Ba, REE, Y, Th, and U in Complex Matrixes: A Combined Approach Based on SIMS and Single-Crystal Structure Refinement

摘要

A procedure was developed for accurate quantification of REE, actinides, and light elements in complex matrixes of interest in earth and material sciences (hellandite and britholite, the REE analogue of apatite). These minerals show a peculiar chemical composition due to the coexist-ence of high amounts of LREE, U, Th with variable quantities of II, U, Be, B, and F. Molecular interferences were resolved, and problems arising from unpredictable matrix effects and lack of reference materials were over-come. X-ray single-crystal structure refinement (SREF), which is not affected by matrix effects and does not require analytical standardization, was used to precisely estimate (by means of both site-scattering value and site geometry) in a wholly independent way the amounts and the distri-bution of the various groups of elements. The combined SIMS—SREF approach allowed us to obtain results of impact for mineralogy and also allowed the accuracy of SIMS investigation to be fixed. The capabilities of SIMS in the quantification of light (Z <6) and heavy (Z >57) elements as both minor and major constituents (~REE(0X) up to -~-~7O wt % in britholite) are shown. This approach may open new perspectives for the in situ analysis of chemically complex niaterials.