GET 212-2023 State Primary Standard for the mass concentration units of oxygen, hydrogen, and carbon dioxide in liquid media

The article examines the accuracy in measuring the mass concentration of dissolved carbon dioxide and the requirements for the accuracy of such measurement, specifically, the relative error in measuring the mass concentration of carbon dioxide (about 10%) at Russian industrial enterprises. The issues associated with ensuring measurement uniformity and achieving the measurement traceability of carbon dioxide mass concentration in liquid media to a state primary standard are considered. GET 212-2023 State Primary Standard for the mass concentration units of oxygen, hydrogen, and carbon dioxide in liquid media is described. GET 212-2023 comprises new technical means: gas supply and gas mixing systems; dissolved carbon dioxide measurement system. The gas supply and mixing systems implement the reproduction method. The programmable measurement system is used to measure the mass concentration of dissolved carbon dioxide. The authors describe a method for reproducing the mass concentration unit of dissolved carbon dioxide relying on the Henry-Dalton law. The results of studying the metrological characteristics of GET 212-2023 are presented. The possibility of reproducing the mass concentration unit of dissolved carbon dioxide within the range of 0–15 g/dm³ is achieved for the first time, with the relative residual systematic error not exceeding 2.5%. In addition, metrological support was developed for performing dissolved carbon dioxide measurement with the accuracy required for the industry. GET 212-2023 can support current needs in various industries such as food, pharmaceutical, and chemical industries, as well as in the field of environmental protection, electronics, and semiconductor technologies.