Information is given on the state primary standard for the pH scale that has been set up at VNIIFTRL The measurement system is described and certification results are given. The future development of pH measurement in Russia is considered.Measurement of pH is one of the commonest methods of monitoring composition for aqueous solutions and other liquid media. Means of measuring pH, or pH meters, are among the leading instruments for analyzing liquids, and there are some millions of them in the Russian Federation. They are used in virtually all branches of industry, as well as in agriculture, ecology, medicine, and scientific research. There are some dozens of standards, recommendations, and other standardization documents dealing with pH measurement. Measurements on pH are made in certifying food products such as meat, milk, milk products, plant oil, grain, wine, and beer as well as in the pharmaceutical and chemical industries.Recent developments in medicine and biotechnology and increased demand for ecological monitoring and the protection of nature have imposed elevated requirements for accuracy in determining pH, and these require reliable standard facilities.The All-Russia Technical Physics and Electronic Measurement Research Institute (VNIIFrR~ has developed a standard for the pH scale that has been confirmed by the Russian State Standard Commi~ion as the state primary standard (GET 54-98).The state primary standard for the pH scale is intended to reproduce, store, and transmit the pH scale in the range from 3.547 to 10.317 in the temperature range from 0 to 95"C. The standard has been confirmed and new editions of the All-Russia state standards have been prepared: "The State System of Measurements: Aqueous Solution pH Scale" (sent for confirmation to the Intergovermnental Council on Standardization, Metrology, and Certification in Minks) and also "The State System of Measurements: State Test Scheme for Means of Measuring pH" (in the stage of agreement with the CIS countries), and this provides for synchronized and more accurate reproduction of the pH scale, while a state test scheme will provide methodological unity and reliability in checking and testing means of measuring pH and will raise the reliability in monitoring product quality.The state primary standard for the pH scale heads the test scheme (see Scheme 1), which governs metrological support in pH measurement and extends to the following means of measurement: pH means with pH measurement ranges from 0 to 14, measurement electrodes with pH measurement ranges from 0 to 14, auxiliary electrodes, and measurement converters for pH meters. Scheme 1 incorporates the current state and future development prospects for pH meters in Russia. It has been formulated in such a way that for each measuring instrument there is established a sequence and method for use in the unified state test scheme.The transfer to the pH scale recommended by the International Union of Pure and Applied Chemistry (IUPAC) and the provision for reproducing the scale at the contempora...
We consider the results of work done at GMNTs VNIIFTR1 based on a high-precision apparatus to create a Russian state primary standard for pH. We present the results of measuring the pH values of buffer solutions (primary standards for pH) and comparison of standards of VNIIFTRI and PTB (Germany).In conformance with the plan for state standardization of the Russian Federation, in 1997 it was proposed to implement a new interstate standard "The pH scale for aqueous solutions" to replace GOST 8.134-74 [1]. The new version of the standard, developed at GNMTs VNIIFTRI, is based on the recommendations of the International Union of Pure and Applied Chemistry (IUPAC) [2]. The new standard raises the precision level for the pH values of the standards (standard solutions), reproducing the pH scale in the interval 0-14 at a temperature of 0-100~ Accordingly, for reproduction and dissemination of the pH scale, the need arose to create a primary state standard, including a measuring apparatus and a set of pH standards (a number of buffered solutions with pH values assigned to them). This work is also important because after the breakup of the USSR, the previous standard was at the Isari NPO [Scientific-Industrial Association] (Georgian Republic).A high-precision apparatus was created and certified in 1993 at VNIIFTRI for metrological assurance for the Russian Federation in the area of pH measurements. Currently, work has been completed on creating a state primary standard for pH; in 1995, a comparison of the VNIIFTRI and PTB (Germany) standards was done.The pH value (hydrogen ion exponent) is defined as the negative log (base 10) of the activity of hydrogen ions in solution: pH = ~ Ig a..
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.