Abstract
A four-variable,five-reaction model is proposed for the family of pH oscillators.All major characteristics of these systems,both those observed in experiments and those found in mechanistic studies, are well represented by the model. The model can be further reduced to two smaller versions. In addition to the characteristic pH oscillation,abroad range of bistability is found in one of the reduced versions.The most important feature, which is common to the three versions,but distinct from other oscillatory models, is the role of the fast protonation-deprotonation equilibrium in generating oscillation.This step plays a role both in the autocatalysis and in the negative feedback.Nine pH oscillators are discussed and explained on the basis of these models.