Realization of a Unified pH Scale - UnipHied

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The concept of pH is very well defined and routinely used in (dilute) aqueous solutions, as well as a few organic solvents and mixed media. However, in most non-aqueous media the possibility of rigorous pH measurement is currently nonexistent. Measured pH values are specific to each solvent and current pH scale is therefore not comparable as it is not solvent-independent. For example, pH 7 in water is neutral, while pH 7 in acetonitrile (MeCN) is strongly acidic.

The aim of the project is to develop a reliable and practical method of measuring and expressing acidity of any medium on a universal scale (pHabs) based on a solvent-independent standard state. The most important specific objectives of UnipHied are (1) to develop and validate a reliable and universally applicable measurement procedure that enables the measurement of pHabs, (2) to create a reliable method for the experimental or computational evaluation of liquid junction potentials between aqueous and non-aqueous solutions, (3) to develop a coherent and validated suite of calibration standards for the purpose of standardizing routine measurement systems in terms of pHabs values for a widespread variety systems


Work Packages

  1. Development and validation of pHabs experimental setup and measurement method
  2. Liquid Junction Potential Determination
  3. Case studies: Applications to Field Practices
  4. Creating impact
  5. Management and coordination

More information

Principal metrologist Teemu Näykki, Finnish Environment Institute SYKE
Tel. +358 295 251 471

Published 2018-08-27 at 14:50, updated 2020-07-30 at 16:02

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