Electrochemical behavior of an anion-exchanger modified electrode prepared by sol-gel processing of an organofunctional silicon alkoxide

Sol-gel films prepared from quaternary amine functionalized silicon alkoxide precursor on electrode surfaces have been investigated as anion-exchange and permselective coatings for electroanalytical investigations. These modified electrodes were evaluated with Fe(CN)₆³⁻ and Ru(bpy)₃²⁺ as the analytes using cyclic voltammetry. At low solution pH, the anionic analyte preconcentrated within the functionalized sol-gel coating and resulted in an improvement in detection limit of about 2 orders of magnitude compared to bare electrodes, but the response for the cationic analyte was suppressed. The modified electrodes are rugged and reproducible and can be regenerated. We have also shown that the anion-exchange and permselective properties of the modified electrodes can be affected by the composition, concentration, and pH of the support electrolyte.