Production and Certification of the Reference Material GSB 04-3258-2015 as a 143Nd/144Nd Isotope Ratio Reference

A new certified reference material, labelled GSB 04-3258-2015, for use as a Nd-143/Nd-144 isotope ratio reference has been prepared by the Institute of Geology, Chinese Academy of Geological Sciences, Beijing. Standardization Administration of the People's Republic of China provided the certification for this reference material. This report presents the reference Nd-143/Nd-144 isotope ratio and supporting production and certification procedures. The reference value was determined by an interlaboratory comparison of results from eleven participating laboratories using MC-TIMS or MC-ICP-MS. The calibration of mass fractionation was conducted by using the exponential law, and the Nd-143/Nd-144 isotope ratios were normalised to the Nd-146/Nd-144 isotope ratio value of 0.7219. Isobaric interference of Sm-144 on Nd-144 was corrected using an interference-free Sm-147/Sm-149 isotope ratio value for mass fractionation. GSB 04-3258-2015 shows sufficient homogeneity and stability for use as an international isotopic reference material. The certified value was calculated from the unweighted means of the results submitted by the participating laboratories. The Nd-143/Nd-144 isotope ratio value for GSB 04-3258-2015 is 0.512438, with a combined expanded uncertainty (k = 2) of 5 x 10(-6). Reference material GSB 04-3258-2015 is available upon request from the Institute of Geology, Chinese Academy of Geological Sciences, and may be used for accurate interlaboratory calibration of Nd isotope analysis.