Permselective and Preconcentration Properties of a Surfactant-Intercalated Clay Modified Electrode

This work is focused on the voltammetric examination of the ion exchange properties of a smectite type clay, before and after its modification by the replacement of its native interlamellar cations (Na+, K+, Ca2+) by hexadecyltrimethylammonium cations (HDTMA+). The raw clay and its organically modified form were first characterized by X‐ray diffraction (XRD) and N2 adsorption–desorption isotherms (BET method) that confirmed the modification via an intercalation process. These materials were subsequently coated onto glassy carbon surfaces, and the resulting modified electrodes were evaluated for the uptake of [Ru(NH3)6]3+ and [Fe(CN)6]3− ions used as redox probes. Some experimental parameters affecting the incorporation of the probes within the film, including the ionic strength, the surfactant loading and the solution pH are thoroughly examined, in order to highlight the mechanism of the process. The possibility of using the surfactant‐intercalated clay modified electrode as an electrochemical sensor for [Fe(CN)6]3− is also evaluated.