Results of pilot comparisons of national standards for the activity of hydrogen ions in aqueous solutions

Abstract

The enormous needs in ensuring the measurement of the hydrogen index in various industries and the national economy of Russia make the measurement of the hydrogen index one of the most important methods for monitoring aqueous media. In 2013, work was carried out to enter into the State Register of Measuring Instruments of the Russian Federation a buffer solution and a standard titer with a pH value of 7.00 – a working pH standard of the 2nd category, which is one of the most demanded of non-standard solutions for verification and calibration pH measuring instruments. To confirm the metrological characteristics, pilot comparisons were organized within COOMET. This article presents the results of a pilot comparison to determine the pH of a phosphate buffer solution – a working standard of рН=7.00. 8 metrological institutes and 10 metrological organizations took part in the comparisons. The results obtained showed that the overwhelming majority of the participants in the comparisons presented the results of pH measurements, which have an uncertainty not exceeding ±0.03 of the average value, which is an acceptable criterion for measuring the pH.