Basaltic and Solution Reference Materials for Iron, Copper and Zinc Isotope Measurements

Abstract

Iron, Cu and Zn stable isotope systems are applied in constraining a variety of geochemical and environmental processes. Secondary reference materials have been developed by the Institute of Geology, Chinese Academy of Geological Sciences (CAGS), in collaboration with other participating laboratories, comprising three solutions (CAGS-Fe, CAGS-Cu and CAGS-Zn) and one basalt (CAGS-Basalt). These materials exhibit sufficient homogeneity and stability for application in Fe, Cu and Zn isotopic ratio determinations. Reference values were determined by inter-laboratory analytical comparisons involving up to eight participating laboratories employing MC-ICP-MS techniques, based on the unweighted means of submitted results. Isotopic compositions are reported in per mil notation, based on reference materials IRMM-014 for Fe, NIST SRM 976 for Cu and IRMM-3702 for Zn. Respective reference values of CAGS-Fe, CAGS-Cu and CAGS-Zn solutions are as follows: d 56 Fe = 0.83 ± 0.07 and d 57 Fe = 1.20 ± 0.13, d 65 Cu = 0.57 ± 0.06, and d 66 Zn = -0.79 ± 0.12 and d 68 Zn = -1.65 ± 0.24, respectively. Those of CAGS-Basalt are d 56 Fe = 0.15 ± 0.07, d 57 Fe = 0.22 ± 0.10, d 65 Cu = 0.12 ± 0.08, d 66 Zn = 0.17 ± 0.13, and d 68 Zn = 0.34 ± 0.26 (2s).

Copper Isotope Ratio Measurements of Cu-Dominated Minerals Without Column Chromatography Using MC-ICP-MS

“…Relative to NIST SRM 976, the NWU-Cu-A solution doped with matrix elements yielded a mean value of 0.91 ± 0.05‰ (2s, n = 5), identical with the reported value of the pure solution (Yuan et al, 2017 ). The δ 65 Cu ratios of GEMOC Cu, GSB-Cu, and CAGS Cu standard solutions are identical with the previously reported values within 2s uncertainties (Hou et al, 2008 ; Liu et al, 2014 ; Yuan et al, 2017 ; Li et al, 2019 ). In this study, the long-term analytical precision of Cu isotopic ratios was evaluated by repeatedly analyzing pure NWU-Cu-A standard solution and chalcopyrite (tc17-25) solution without column chromatography using MC-ICP-MS.…”

Direct measurement of Fe isotope compositions in iron-dominated minerals without column chromatography using MC-ICP-MS

“…Relative to IRMM-014, the Alfa Fe-1 solution doped with matrix elements yielded a mean δ 56 Fe value of 0.35 ± 0.04‰ (2sd, n = 5), and CAGS Fe doped with matrix elements yielded a mean δ 56 Fe value of 0.81 ± 0.05‰ (2sd, n = 5). The δ 56 Fe values of Alfa Fe-1 and CAGS Fe standard solutions are identical to previously reported values (0.34 ± 0.04‰ 67 and 0.83 ± 0.07‰, 76 respectively) within 2sd uncertainties. The measured Fe isotopic composition of rock standard reference materials (BCR-2, BHVO-2, GSR-1 and GSR-3) were consistent with reported values 63,67,77 within 2sd uncertainties, which were treated with the described column chromatography procedure.…”

“…Four Fe solutions Alfa Fe-1 (Alfa Aesar, 10 mg mL −1 stocked in 5% HNO 3 ), 67 Alfa Fe-2 (Alfa Aesar, plasma standard solution, 10 000 μg mL −1 , stock # 47221, lot # 205298) and NWU-Fe (GSB 04-1726-2004, ID INT17A004-2, 1000 μg mL −1 ) are the reference materials of Fe used as the in-house Fe standards in the State Key Laboratory of Continental Dynamics (SKLCD), Northwest University, China. CAGS Fe ( δ 56 Fe = 0.83 ± 0.07‰ (2SD) and δ 57 Fe = 1.22 ± 0.13‰ (2SD)) 75,76 used for unknown samples for quality control. The Fe isotope ratios of Alfa Fe-1 and NWU-Fe are δ 56 Fe = +0.343 ± 0.031‰ 67 and δ 56 Fe = 0.70 ± 0.03‰, respectively, relative to the reference material IRMM-014.…”

Geostandards and Geoanalytical Research Bibliographic Review 2019

“…Several articles in 2019 addressed the determination of lithium isotopes: (a) Li et al . (2019a) reported a new dual‐column system for lithium purification to achieve accurate and precise analysis of lithium isotopic compositions using a multi‐collector inductively coupled plasma‐mass spectrometer (MC‐ICP‐MS). (b) Lin et al .…”