a Unified Ph Scale for All Solvents: Part I – Intention and Reasoning

The definition of pH, its measurement and standard buffers, is well developed in aqueous solutions. Its definition in solvents other than water has been elaborated for a couple of solvents and their mixtures with water. However, the definition of a universal pH scale spanning all solvents and phases, not to mention standard procedures of measurement, is still a largely uncharted territory. UnipHied is a European collaboration and has the goal of putting the theoretical concept of an earlier introduced (2010) unified pHabs scale on a metrologically well-founded basis into practice. The pHabs scale enables the comparability of acidity between different phases. This article draws the connection of the concepts of unified acidity and secondary pH measurement.