Potentiometric determination of anionic surfactants using a new ion-pair-based all-solid-state surfactant sensitive electrode

An all-solid-state surfactant sensitive electrode has been prepared, based on a teflonised graphite conducting substrate coated with plasticised PVC-membrane containing a new synthesized tetrahexadecylammonium-dodecylsulfate as anionic surfactant sensing material. The electrode exhibited Nernstian response (58.1 mV/decade) for dodecylbenzensulfonate and a near-Nernstian response (64.2 mV/decade) for dodecylsulfate. The electrode was used as end-point indicatior for potentiometric surfactant titrations. The selectivity coefficients relating to the common inorganic and organic anions have been calculated by modelling of Nikolskii–Eisenman equation. Several commercial surfactants have been also titrated. The electrode enables the titration of shorter hydrocarbon chain anionic surfactants, as well.