New Standard Solutions for Measurement of Iron, Copper and Zinc Isotopic Compositions by Multi-collector Inductively Coupled Plasma-Mass Spectrometry

Abstract

In recent decades, Fe, Cu and Zn isotopes have been the hot topic with the development of analytical methods of these isotopes. However, the standard materials for isotope analysis are very sparse. There is only one Fe isotope standard material and one Zn isotope standard in The European Institute for Reference Materials and Measurements (IRMM). The former is sold out and therefor unobtainable, whereas the latter is expensive. There is one Cu isotope standard material in National Institute of Standards and Technology (NIST). In order to adapt to the development of Fe, Cu and Zn isotope analyses in China, three new standard solutions to be used as references for Fe, Cu and Zn isotopic composition have been prepared in the Institute of Geology, Chinese Academy of Geological Sciences, Beijing. Fe, Cu and Zn isotopic standard solutions are named CAGS-Fe, CAGS-Cu and CAGS-Zn, respectively. Fe, Cu and Zn isotopic compositions of these standard solutions were measured by high precision Nu Plasma High-resolution Multi-collector Inductively Coupled Plasma-Mass Spectrometry (MC-ICP-MS). Three standard solutions show high homogeneity and stability by F investigation. The Fe, Cu and Zn isotopic compositions have shown no obvious variations over 38 months, indicating good homogeneity. The reference values for standard solutions and their associated uncertainties at 95% confidence level are 0.80±0.05 (δ56FeIRMM014, ‰), 1.20±0.10 (δ57FeIRMM014, ‰), 0.57±0.06 (δ65CuNBS976, ‰), -0.77±0.10 (δ66ZnIRMM3702, ‰) and -1.55±0.13 (δ68ZnIRMM3702, ‰). Standard solutions can be used for instrumental calibration and analytical monitoring, which is meaningful for inter-laboratory data comparison.

Keywords

• fe-cu-zn isotopes
• standard solution
• prophetic values
• multi-collector inductively coupled plasma-mass spectrometry