NEW VOLTAMMETRIC SENSORS FOR ALKALINE CATIONS BASED ON IONOPHORES INCORPORATED INTO A SELF-ASSEMBLED THIOL MONOLAYER

摘要

Ion-channel sensors (ICSs), largely used to electrochemically detect electroinactive various chemical species, have been applied to determine the concentration of Li~+ and K~+ cations in aqueous solutions, via ionophores immobilized on the surface of gold electrodes. The preparation of these new voltammetric sensors has been performed by modifying the gold surface with a thiol self-assembled monolayer (SAM) and by embedding the commercial ionophore into the SAM. The measurements were performed with the addition of electroactive species, the markers. The interactions between the cation and the ionophore control the rate of marker redox reaction, thus revealing the existence of the analyte. The possibility of using ionophores embedded into a thiol SAM leads to a new type of ICSs reliable, selective and, in particular, easy and rapid to prepare. The successful and durability of the embedment process depend the physico-chemical properties which govern the interactions between ionophore and thiol molecules.