Preparation and Certification of A Titanium Isotopic Standard Solution

Titanium isotopic compositions have been used to elucidate geochemical and cosmochemical processes. Until now, no Ti isotopic reference material has been reported worldwide, which imposes restriction upon analytical method establishment and laboratory quality control. In this paper, a newly prepared Ti isotopic standard solution is introduced. Ti element standard solution offered by the Alfa Company from U.S.A. was chosen as the starting material, based on the comparison of Ti isotopic measurement results of 3 commercially available Ti element standard solutions. The preparation of the new standard solution was strictly followed using the stipulation on reference material of the metrological technical standard of state, including homogeneity and stability tests, and certification analyses. 150 bottles of the solution were prepared, among which 15 bottles were selected randomly for homogeneity test and no detectable heterogeneity was found by F test. The stability inspection through 30 months indicated no significant changes on δTi values. The certified values and uncertainty at the 95% confidence level were shown to be: δ⁵⁰Ti=-2.23‰±0.14‰, δ⁴⁹Ti=-1.67‰±0.09‰,δ⁴⁸Ti=-1.13‰±0.06‰ andδ⁴⁷Ti=-0.57‰±0.05‰. This newly certified standard solution can be used to calibrate instruments and verify analytical quality in Ti isotope measurements, and compare inter-laboratory data.