Publications Repository - Helmholtz-Zentrum Dresden-Rossendorf

While in-situ analytical instrumentation for the direct elemental and isotopic analysis of solid materials has undergone continuous and significant improvement over recent years, development of well-characterized and homogeneous microanalytical reference materials (MRM) for calibration and validation of analytical data has been delayed. Ideally, MRM must be homogeneous down to the single micrometer scale for major, minor, trace, and ultra-trace elements and isotopes, withstand high-vacuum and impact of high-energy electron, ion, and photon beams, stable in its physical and chemical properties over time and under various environmental conditions, certified following ISO guidelines, and available for a wide variety of materials.
We developed a method for manufacturing undiluted, binder-free pressed powder pellets[1] with particle grain size down to the nanometer range (D50 <170 nm), extremely low roughness of pellet surface (RA <50 nm), and excellent within and between pellet homogeneity. This technique has been applied so far to a wide range of very different sample types: biogenic carbonates (foraminifera, clam shells, red algae, corals), speleothem, silicate rocks, iron ores and banded iron formation, manganese nodules, sulphides UQAC-FeS, refractory minerals, plutonic and volcanic rocks, fly ash, bone-apatite, minerals for Rb/Sr age-dating[2] etc.. We successfully blended different materials opening new ways for producing e.g., series of elemental and isotopic calibration standards. These “nanopellets” have been successfully used with LA-ICP-MS, LIBS, µ-XRF, handheld-XRF instruments, and with EPMA, PIXE, SIMS. Hence, nanopellets proved to be a new and, possibly, universal matrix-matched MRM for many custom solid materials to be used with many in situ analytical techniques.
In addition, this way of sample preparation bears the potential of completely replacing conventional tedious and time-consuming wet-chemistry procedures for bulk analysis, and this holds true in particular for refractory samples like ceramics, granites, ultramafic rocks, and samples with volatile or easy-to-contaminate components (e.g., B). Here we give an overview of the present state of development of new MRM[3] and their characterization in terms of grain size distribution, surface topography, porosity, homogeneity, and accuracy of analytical results for both elemental (major, minor, trace and ultra-trace elements) and isotopic (Sr, Li, B, O) composition.

[1 ] Garbe-Schönberg D & Müller S, JAAS, 29, 990 (2014); [2] Hogmalm KJ, et al., JAAS, 32, 305 (2017); [3] www.my-standards.com; see also paper by D. Savard et al., this conference