Türkiye Ulusal Metroloji Enstitüsü’nde Sertifikalı pH Tampon Çözeltilerinin Üretimi

Abstract

pH, a thermodynamic function, is the negative logarithm of the activity of hydronium ions. It is well-known concept used in many different areas from science to industry. The widespread use of pH measurements has increased the need for certified reference solutions in this field. The primary pH measurement system that was established in Turkey as the first and only was used for production and certification of reference pH buffer solutions. The system consists of measurement cell named as Harned cell, Ag/AgCl electrodes, Pt/Ptblack or Pt/Pdblack electrodes, thermostatic bath, PT-100 probe and display unit, data acquisition unit and barometer. The software of primary system was developed and validated in TUBITAK UME. Moreover, high precision coulometry system has been used to determine the acid molality utilized at first step of primary level pH measurement system. Homogeneity, short and long term stability, characterization, certification and post-production studies were performed according to ISO Guide 34: 2009, ISO Guide 35: 2006 and ERM Application Note 1: 2010 for the production and evaluation of the results of certified pH buffer solutions. Thanks to this situation, traceability will be disseminated through TUBITAK UME directly. Moreover the foreign currency spent for these solutions, that are generally used for calibration of pH meters and used in many other areas, will be retained in the country.