Constant chemical potential titration. Application to determination of nonionic surfactant concentrations

Titration is most often associated with the idea of a stoichiometric reacti on. Generally, it is not considered possible to titrate a compound against a reagent unless the titration reaction is near total and if the result is not a product of well-defined stoichiometry. In this work, we illustrate th at accurate titration is possible with compounds and reagents that interact to form an association of undefined stoichiometry, Our model is the potent io-metric titration of nonionic surfactant with cationic surfactant using a cationic surfactant-selective electrode. The result of this reaction is mi xed micelles, the composition of which depends on the concentrations of the two surfactants in solution.