Preparation of reference material of lithium isotope for laboratory

Two kinds of Li2CO3 materials with different isotope abundance were purified,respectively.The reference material of lithium isotope for laboratory and its spike were prepared.The homogeneity and stability of the reference material were tested.A accurate absolutely measuring technique of lithium isotope abundance based on isotopic dilution mass spectrometry(IDMS) theory was established.The characterisation of the reference material was done by means of this technique.Lithium isotope reference material(IRMM 016) was measured,and the reliability of the characterisation of the reference material was validated.The results of the characterisation and the evaluated uncertainty of the reference material showed that the 7Li isotope abundance of the prepared reference material was(91.538±0.019)% at the 95% confidence level.