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{{Short description|Universal pH buffer used for the pH range from 2 to 12}}
The '''Britton–Robinson buffer''' ('''BRB''' or  '''PEM''') is a "universal" [[pH]] [[Buffer solution|buffer]] used for the pH range from 2 to 12. It has been used historically as an alternative to the [[McIlvaine buffer]], which has a smaller pH range of effectiveness (from 2 to 8).<ref>{{cite journal|journal=Annali di Chimica|first1=Carlos|last1=Mongay|first2=Víctor |last2=Cerdà|title=A Britton-Robinson Buffer of Known Ionic Strength|volume=64|date= January 1974|url=https://www.researchgate.net/publication/285064939}}</ref>

Universal buffers consist of mixtures of acids of diminishing strength (increasing [[Acid dissociation constant|p''K''<sub>a</sub>]]), so that the change in pH is approximately proportional to the amount of alkali added. It consists of a mixture of 0.04&nbsp;M [[boric acid]], 0.04&nbsp;M [[phosphoric acid]] and 0.04&nbsp;M [[acetic acid]] that has been titrated to the desired pH with 0.2&nbsp;M [[sodium hydroxide]]. Britton and Robinson also proposed a second formulation that gave an essentially linear pH response to added alkali from pH 2.5 to pH 9.2 (and buffers to pH 12). This mixture consists of 0.0286&nbsp;M [[citric acid]], 0.0286&nbsp;M [[monopotassium phosphate]], 0.0286&nbsp;M boric acid, 0.0286&nbsp;M [[Barbital|veronal]] and 0.0286&nbsp;M [[hydrochloric acid]] titrated with 0.2&nbsp;M sodium hydroxide.

The buffer was invented in 1931 by the English chemist Hubert Thomas Stanley "Kevin" Britton (1892–1960) and the New Zealand chemist [[Robert Anthony Robinson]] (1904–1979).<ref>{{cite journal |title=The use of the antimony–antimonous oxide electrode in the determination of the concentration of hydrogen ions and in potenliometric titrations. The Prideaux–Ward universal buffer mixture |url=https://pubs.rsc.org/en/content/articlelanding/1931/jr/jr9310000458 |journal=Journal of the Chemical Society (Resumed) |year=1931 |publisher=Royal Society of Chemistry|doi=10.1039/JR9310001456|pages=747–748 |last1=Britton |first1=Hubert Thomas Stanley |last2=Robinson |first2=Robert Anthony }}</ref>

==See also==
* [[Buffer solution]]
* [[Good's buffers]]

==References==
{{Reflist}}

{{DEFAULTSORT:Britton-Robinson buffer}}
[[Category:Acid–base chemistry]]
[[Category:Buffer solutions]]
[[Category:Chemical tests]]


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