A fast double stack chromatographic separation of Germanium from silicate material for isotope analysis with MC-ICP-MS

Abstract

Germanium (Ge) isotope measurements (δ^74/70Ge relative to NIST3120a) have attracted increasing attention in geochemistry and cosmochemistry; however, analyses of silicate material with low Ge contents remain difficult due to complex sample preparation and purification procedures. Here we present a novel double stack chromatographic procedure that purifies Ge from silicate digests. This protocol reduces evaporation steps and overall processing time, allowing higher sample throughput while preserving quantitative Ge recovery (~100 %) and low procedural blanks (<0.1 ng Ge), together with effective matrix removal. Because Ge yields are quantitative under the conditions tested, this method is suitable for measuring Ge isotope signatures without the need of a double spike. This fast, user-friendly chemistry should broaden routine use of Ge isotopes in isotope geo- and cosmochemistry.