The quinhydrone electrode may be used to measure the hydrogen ion concentration (pH) of a solution containing an acidic substance.
[1][2] Quinones form a quinhydrone cocrystal by formation of hydrogen bonding between ρ-quinone and ρ-hydroquinone.
[4] Quinhydrone electrodes provide fast response times and high accuracy.
However, it can only measure pH in the range of 1 to 9 and the solution must not contain a strong oxidizing or reducing agent.
[5] however, it is not reliable above pH 8 (at 298 K) and cannot be used with solutions that contain a strong oxidizing or reducing agent.