A new type of synthetic geochemical reference material—SynTERM

Abstract

Analytical data reported for natural geological reference materials (GRMs) indicates uncertainty in the recommended element concentrations, varying levels of both inhomogeneity in the distribution of trace elements and chemicaYphysica1 instability. Two types of silica gel-based synthetic trace element reference materials (SynTERM) have been developed as alternatives to natural GRMs: (i) high-purity reference materials and (iz] standard additions to existing natural geological materials. Wide variations in the concentration and combination of trace elements have been successfully formulated. The gel is formed by the rapid alkaline hydrolysis of tetraethyl orthosilicate (TEOS). Depth profiling by X-ray photoelectron spectrometry indicates that the trace metals are homogeneously distributed throughout gel particles of mean size 25 pm. Relative variation in results for trace elements in the high-purity reference materials (inhomogeneity) was less than k 1.5% for a 1 g sample and less than k 12% for 0.05 g samples. Compared with many natural GRMs SynTERM reference materials are more homogeneous, cheaper to produce and of potentially infinite supply-

Reflections of the geological characteristics of Cyprus in soil rare earth element patterns

“…INAA analyses were monitored using soil reference material USGS GXR-6 (Gouveia et al, 1994) and four Actlabs in-house till reference materials. Field-portable XRF analyses were monitored using synthetic reference material SynTerm 12 (Cohen and Beck, 1995) and USGS GXR-6. Detection limits are listed in Table S1.…”