A synthesized sphalerite standard for in situ analysis of sulfur isotopes and trace elements by LA-MC-ICP‒MS and LA-ICP‒MS

Abstract

In situ microanalysis of the sulfur (S) isotope composition and elemental distribution in sphalerite are important in geochemistry. Matrix-matched reference material is still deficient for in situ microanalysis. In this study, a hydrothermal synthesis method combined with hot-press sintering processes was used to synthesize a ZnS material Sph-LD. A large number of in situ microanalysis, including trace element concentrations and S isotope compositions, were performed on Sph-LD by laser ablation inductively coupled plasma mass spectrometry (LA-ICP‒MS) and laser ablation multi-collector inductively coupled plasma mass spectrometry (LA-MC-ICP‒MS) to assess the homogeneity. The LA-MC-ICP-MS results are highly consistent and yield a mean δ34S value of + 17.11 ± 0.20‰ (2s, n=560), which is analogous with that measured by IRMS. Microanalysis of element concentrations generally agree with the data of ICP-MS within 10 % for trace elements (relative standard deviation < 10 %). These results indicate that Sph-LD is suitable to be a matrix-matched reference material available for quantitative analysis of element concentrations and S isotope measurement of sphalerite using LA-ICP‒MS and LA-MC-ICP‒MS. Meanwhile, the synthetic method introduces a novel concept for the development of standard materials.