Modified chromatographic separation scheme for Sr and Nd isotope analysis in geological silicate samples

A novel chromatographic separation technique for Sr and Nd separation from geological silicate samples was established and successfully tested for routine use in Laboratory of Radiogenic Isotopes of the Czech Geological Survey. The separation scheme is based on combination and modification of methods published in papers by Christian Pin and his co-workers. This triple column arrangement enables the isolation of pure Sr and Nd fractions (also Sm if required) from bulk-rock solution in a single step during one working day. The Sr and Nd yields are high, while blank levels remain low. This procedure minimizes the acid consumption and time needed for the separation by more than half compared to the traditional ion exchange separation techniques. The calibration of the Ln.Spec columns should be periodically monitored because the elution of REEs shifts after a period of extensive use of the resin. Suitability of this technique for Sr and Nd separation from silicate rock samples was confirmed by repeated measurements of 87 Sr/ 86 Sr and 143 Nd/ 144 Nd isotopic ratios in three international reference materials BCR-1, JA-1 and JB-3.