Domestic Status Quo and Quantity Value Verification of Certified Reference Materials for Electrolytic Conductivity

The certified reference materials (CRMs) for electrolytic conductivity are crucial to ensuring accurate and consistent conductivity measurement results. In this paper, the current situation of existing conductivity CRMs in China is reviewed in terms of their characterization methods and scope of application, and the characteristics of existing CRMs and their shortcomings are analyzed in depth. In view of the current situation that more than 50% of the existing conductivity CRMs in China are characterized by comparative measurement methods, the primary standard for the conductivity of electrolyte solutions was used to verify the values of these CRMs. The results of the verification show that: the accuracy and quality of the comparative measurement method for the characterization of the CRMs are poor (overall pass rate of 58%, the rate of CRMs with lower characterization values is 20%), and there is an urgent need to strengthen the market regulation in the process of replication of the reference materials. When the comparative measurement method for the characterization of the CRMs is being applied, several important technical aspects deserve attention, namely, the accuracy level of the conductivity meter used, the accurate determination of the conductivity of type II water in the laboratory, the correction of the air buoyancy when weighing the mass, the accurate fixing of the solution volume, and the scientific and reasonable assessment of the uncertainty of the characterization of the CRMs.