Advances in preparing techniques for geochemical reference materials in China.

In this paper, we have reviewed the advances in techniques and methods for the preparation of geochemical reference materials in China, which include sample processing, particle size determination and characterization, homogeneity test and evaluation, determination of minimum sample mass, stability test and its results expression, certification style, analytical methods, data processing and certification requirements, uncertainty evaluation and traceability, and so on. In addition, we discuss the present situation and future development for the preparation of geochemical reference materials in China according to the Chinese national technical specifications, the guides of International Organization for Standardization (ISO) and the protocol of the International Geological Association (IAG).