As the first stage of the development of a new isotope geochemical proxy for understanding the evolution processes of geo and planetary systems, we devised a high-purity separation and measuring technique for stable isotopes of rare earth elements (Fig. 1).
Fig. 1. (a) MC-ICP-MS instrument for isotope analysis and (b) high-purity separation outcomes among Sm, Eu and Gd.
This technique is very important for measuring Eu stable isotopes of 151Eu and 153Eu. In this study, we succeeded in realizing a high quality level of ca. 99.99% during the separation of the Eu fraction from the geological materials. (c) Based on experiments using the developed method, we could observe some differences in the Eu isotope ratio from certain standard geochemical rocks, suggesting the possibility of Eu isotope fractionation in the geological system. Note that (Eu/*Eu)CN refers to an Eu anomaly in the chondrite-normalized REE pattern, which is related to the abundance of rare earth elements in geological materials. This anomaly arose during the evolution processes of magma in the earth system. The numbers refer to the degree of the Eu anomaly. In addition, δ151Eu indicates the degree of Eu isotope fractionation. Essentially, the value of δ151Eu is "0" because Eu has only two stable isotopes, 151Eu and 153Eu.