Reference Material Preparation of ¹⁴³Nd/¹⁴⁴Nd Isotope Ratio

¹⁴³Nd/¹⁴⁴Nd isotope ratio is the key for Sm-Nd isotope method. The ¹⁴³Nd/¹⁴⁴Nd isotope ratio of geological samples varies within a small range, and thus the ¹⁴³Nd/¹⁴⁴Nd isotope ratio analysis must be precise. In order to obtain high precision and high accuracy of the analytical data, the analysis process involving Nd isotope reference material plays an important role. The previous Nd isotope reference material is neodymium oxide, which have been exhausted in recent three decades. A national reference material of ¹⁴³Nd/¹⁴⁴Nd isotope ratio was introduced in this paper, which shows sufficient homogeneity and stability. The certified value of this reference material was determined by eleven participating laboratories using MC-TIMS and MC-ICP-MS. The ¹⁴³Nd/¹⁴⁴Nd isotope ratio value for the reference material is 0.512438, with a combined expanded uncertainty (k=2) of 5×10^-6. The standard solution gets certification in May, 2015 and the Serial number is GSB 04-3258—2015. The standard solution can be used for quality monitoring of the equipment calibration and analysis process during the ¹⁴³Nd/¹⁴⁴Nd ratio determination for geology, resources, ocean, environment, archaeological and other type samples.