Single-Stage Extraction Technique for Ce Stable Isotopes and Measurement by MC-ICP-MS

The separation of Ce from other rare earth elements has not been well established because of their similar geochemical properties. In this study, we report a single-stage extraction technique to purify Ce from natural samples with Eichrom DGA resin. This method separates Ce effectively from matrices and interfering elements, such as Ba, La, and Nd. The Ce elution curve would not drift with different Ce loading masses and rock types. The Ce isotope compositions were measured using a Thermo Scientific Neptune Plus multicollector (MC)-inductively coupled plasma (ICP)-mass spectrometry (MS) instrument. The instrumental mass bias of Ce isotopes was corrected with a sample-standard bracketing combined with a Sm-doping method. The delta Ce-142 values of standard solutions (CDUT-Ce and JMC304) relative to National Institute of Standards and Technology SRM 3110 measured were +0.128 +/- 0.028 parts per thousand(2SD, N = 30) and 0.005 +/- 0.038 parts per thousand (2SD, N = 30), respectively. The reproducibility for delta Ce-142 was better than 0.040 parts per thousand. The Ce isotopic compositions of nine United States Geological Survey standard rocks, including carbonatite, basalt, andesite, quartz latite, dolerite, rhyolite, and granodiorite, were measured in this study. Our result showed that delta Ce-142 values of these rocks varied slightly, indicating that insignificant fractionation occurred during igneous processes. The technique proposed in this study is simple and time-efficient, which is beneficial for further studies on Ce isotope geochemistry.

Automated summary

This study presents a simple and time-efficient technique for purifying Ce from natural samples, with good reproducibility of Ce isotope compositions indicating minimal fractionation during igneous processes. The method can be beneficial for further studies on Ce isotope geochemistry.