pH MEASUREMENT CAPABILITY THROUGH THE PRIMARY pH MEASUREMENT OF CARBONATE BUFFER SOLUTION

Paulo Paschoal Borges, Isabel Cristina S. Fraga, Bianca de Souza R. Marques, Júlio C. Dias, Sidney Pereira Sobral, Wiler Batista da S. Junior, Carla de M. Ribeiro, Jéssica C. Lopes, Valnei S. Cunha

Abstract

The Chemical Metrology Division (Dquim) from National Institute of Metrology, Standardization and Industrial Quality - Inmetro established in 2003 the primary system of pH measurement. The main use of this system is to provide reliability and traceability to the pH measurements in Brazil since its measurement is one of the most important analyses carried out in many laboratories all over the country. In order to show comparability and capability in primary pH measurement, Inmetro participated in both the key-comparisons CCQM-K18 and in the supplementary comparison that followed, named CCQM-K18.1, to measure the pH in a carbonate buffer solution of nominal value of pH 10. Both exercises were organized by Consultative Committee for Amount of Substance (CCQM) of the International Bureau of Weights and Measures (BIPM). This work aimed at showing the development and optimization of the primary pH system from Inmetro in order to participate in the supplementary key-comparison. Inmetro´s results in that supplementary comparison have shown its capability in primary measurement of pH 10.

Keywords

primary pH measurements, key-comparison, carbonate buffer

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DOI

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IMEKO TC

TC24 - Chemical Measurements

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