Additive manufacturing of platinum group element (PGE) reference materials with a silica matrix

Abstract

Rationale The microanalytical community has an outstanding need for platinum group element (PGE) reference materials, particularly for trace element analysis by laser ablation inductively coupled plasma mass spectrometry (LA‐ICPMS). National Institute of Standards and Technology (NIST) glasses contain Rh, Pd, and Pt, but lack Ru, Os, and Ir. Synthesis of silicate PGE standards has proven difficult due the tendency of PGEs to form metallic nuggets. Methods Additive manufacturing methods were used to produce PGE standards with a silica matrix. Monodispersed submicron PGE‐doped Stöber particles were used as feedstock materials for electrophoretic deposition (EPD). Two‐cm‐sized samples produced by EPD were subsequently densified by thermal processing. The homogeneity of PGEs was tested using LA‐ICPMS and concentrations were measured by laser ablation and solution ICPMS. Results The PGE concentrations ranged from 0.5 to 3 μg/g. The inhomogeneity was at the 3% RSD level for Ru, Rh, Ir, and Os throughout and 5% for Pt and Pd in the interior of the samples. Based on LA‐ICPMS analyses, the interiors of the two samples have near identical concentrations in PGEs. Conclusions The samples fabricated in this study represent the most complete and homogeneous PGE standards produced with a silicate matrix. The ability to produce multiple samples with the same composition provides opportunities for validating methods, monitoring long‐term reproducibility, and facilitating interlaboratory comparisons.

Atomic spectrometry update – a review of advances in environmental analysis

“…There is an ongoing interest in the synthesis and characterisation of microanalytical RMs for in situ microbeam technologies such as SIMS, LA-ICP-MS, LIBS and EMPA. One study described 206 the production of PGE RMs from sub-mm-size PGE-doped silica particles. These doped particles were used as feedstock materials for electrophoretic deposition followed by thermal processing to fabricate two cm-sized materials with PGE concentrations between 0.5 to 3 mg g À1 .…”

“…The doped elements in the resulting calcite RMs were homogenously distributed (<12%, 2RSD). As the 207 Pb/ 206 Pb ratio varied by <1% and the 238 U/ 206 Pb ratio by 3-24%, depending on element mass fractions, these synthetic RMs were considered to be a promising alternative to natural calcite RMs for U-Pb geochronology. Courtney-Davies et al 208 used ID-TIMS and LA-ICP-MS to characterise cm-sized chips of a synthetic haematite RM called MR-HFO.…”

“…The homogeneity of major elements (<5 wt% RSD) was demonstrated by EPMA and that of the U-Pb and Th-Pb systems (<2% RSD) by SIMS. The recommended age data (a 206 218 as a potential RM for micro-beam U-Pb geochronology and Hf-O isotopic analysis. A mean ID-TIMS 206 Pb/ 238 U age of 533.7 AE 3.7 Ma (2SD, n ¼ 8) was recommended as the working value when using untreated grains for calibration.…”

“…The recommended age data (a 206 218 as a potential RM for micro-beam U-Pb geochronology and Hf-O isotopic analysis. A mean ID-TIMS 206 Pb/ 238 U age of 533.7 AE 3.7 Ma (2SD, n ¼ 8) was recommended as the working value when using untreated grains for calibration. Results obtained by SIMS and LA-ICP-MS were in agreement with the ID-TIMS data within the uncertainties of these techniques.…”

Trends in selected fields of reference material production

“…They used monodispersed submicron PGE–doped silica particles produced by Stöber synthesis as feedstock materials for electrophoretic deposition (EPD). This new RM is intended for use for calibrating laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) instruments, substituting the NIST glasses SRMs 610–617 [ 16 ]. NIST considers also producing ceramic CRMs in connection with specific ceramics AM fabrication routes.…”