Mg Isotope Interlaboratory Comparison of Reference Materials from Earth‐Surface Low‐Temperature Environments

摘要

> To enable quality control of measurement procedures for determinations of Mg isotope amount ratios, expressed as δ 26 Mg and δ 25 Mg values, in Earth‐surface studies, the δ 26 Mg and δ 25 Mg values of eight reference materials ( RM s) were determined by interlaboratory comparison between five laboratories and considering published data, if available. These matrix RM s, including river water SLRS ‐5, spring water NIST SRM 1640a, Dead Sea brine DSW ‐1, dolomites JD o‐1 and BCS‐CRM 512, limestone BCS‐CRM 513, soil NIST SRM 2709a and vegetation NIST SRM 1515, are representative of a wide range of Earth‐surface materials from low‐temperature environments. The interlaboratory variability, 2 s (twice the standard deviation), of all eight RM s ranges from 0.05 to 0.17‰ in δ 26 Mg. Thus, it is suggested that all these materials are suitable for validation of δ 26 Mg and δ 25 Mg determinations in Earth‐surface geochemical studies.