Isoionic point (original) (raw)

The isoionic point is the pH value at which a zwitterion molecule has an equal number of positive and negative charges and no adherent ionic species. It was first defined by S.P.L. Sørensen, Kaj Ulrik Linderstrøm-Lang and in 1926 and is mainly a term used in protein sciences. For a diprotic acid, the hydrogen ion concentration can be found at the isoionic point using the following equation * hydrogen ion concentration * first acid dissociation constant * second acid dissociation constant * dissociation constant for water * concentration of the acid