Permselectivity and ion-exchange properties of Eastman-AQ polymers on glassy carbon electrodes

Eastman-AQ55D is a new poly(ester sulfonic acid) cation exchanger available in a commercial dissolved form. Films of this polymer were coated onto glassy carbon surfaces, and the resulting electrodes exhibit attractive permselectivity, ion-exchange, and antifouling properties. Substantial improvement in the selectivity is observed as a result of excluding anionic species from the surface. The charge-selective behavior is demonstrated in the presence of a variety of compounds of neurological significance. A rapid response to dynamic changes in the concentration of cationic and neutral species is observed. The polymer strongly binds multiply charged counterions. Cyclic voltammetry is used to determine the quantity of incorporated ions as a function of time, concentration, and other variables. The oxidation of hydrogen peroxide is catalyzed when Ru(bpy)3(2+) is incorporated in the coating. The film can also protect the substrate electrode from foulants present in the contacting solution. These features, as well as the low cost, simple coating procedure, strong adherence to surfaces, and versatility, make the Eastman-AQ55D polymer well-suited for a variety of electro-analytical applications.