Term: primary pH standards
https://doi.org/10.1351/goldbook.P04837

Definition:
Certain substances which meet the criteria of:   reproducible preparation in a highly pure state;   stability of solution over a reasonable period of time;   having a low value of the residual liquid junction potential;   having pH betwen 3 and 11.  

Related Terms:
1) liquid junction (http://doi.org/10.1351/goldbook.L03584).

Source: Orange Book, 2nd ed., p. 19 (https://media.iupac.org/publications/analytical_compendium/)

Citation: 'primary pH standards' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. https://doi.org/10.1351/goldbook.P04837

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