Determination of Gallium Isotopic Compositions in Reference Materials

• Published in: Geostandards and geoanalytical research Vol. 43; no. 4; pp. 701 - 714
• Main Authors: Feng, Lan‐ping, Zhou, Lian, Liu, Jinhua, Hu, Zhao‐chu, Liu, Yong‐sheng
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc 01.12.2019
• Subjects: C‐SSBIN correction method; Ferromanganese nodules; Fractionation; Gallium; Geology; Isotope fractionation; Isotopes; MC‐ICP‐MS; Nodules; Reference materials; Silicates; Stable isotopes
• ISSN: 1639-4488; 1751-908X
• DOI: 10.1111/ggr.12294

The interest in the study of gallium (Ga) stable isotope fractionation in low‐ and high‐temperature environments has increased significantly in the last few years. However, a unified reference material (RM) is still lacking for the Ga isotope research community, which hinders interlaboratory comparison between different groups. Consequently, certification of Ga isotopic reference materials for interlaboratory comparison is of high priority. In this study, Ga isotope ratio data for ten geological RMs including silicates, shales and ferromanganese nodules, and two pure Ga RMs including NIST SRM 994 and NIST SRM 3119a reported by three different groups, were determined by MC‐ICP‐MS. Sample matrices of geological RMs were separated by a two‐column separation method with the use of AG MP‐1M and AG 50‐X8 resin, separately, and quantitative recoveries of > 99% Ga were obtained for all geological RMs. Instrumental mass bias was corrected by the combined calibrator‐sample bracketing and internal normalisation model. Validation of the proposed method was performed by analysing synthetic solutions. After normalisation of all available δ71Ga data of geological RMs to a single Ga RM, results obtained in our study are in agreement with previously reported results. Key Points Gallium isotopic compositions of ten geological reference materials and two pure Ga reference materials were determined by MC‐ICP‐MS. A two‐column separation method was developed for Ga isotope measurement. Excellent interlaboratory agreement indicates data accuracy.