Functionalized ormosils-based biosensor. Probing a horseradish peroxidase-catalyzed reaction

Abstract

We report herein the electrochemistry of redox materials encapsulated with organically modified sol-gel glasses (ormosil). The ormosils that encapsulated ferrocene monocarboxylic acid and potassium ferricyanide are made using palladium-linked 3-glycidoxypropyltrimethoxysilane, trimethoxysilane, HCl, and an aqueous solution of potassium ferricyanide or ferrocene monocarboxylic acid followed by gelation of the same for 24 h at 30°C. The requirement of palladium linkage with ormosil is also examined and data on the electrochemistry of (i) only potassium-ferricyanide encapsulated ormosil without palladium, (ii) potassium-ferricyanide encapsulated ormosil with varying concentrations of palladium are reported. The ormosil made with optimum concentrations of palladium shows better redox electrochemistry as compared to that made without palladium. The ormosils are converted into fine powder followed by incorporation together with horseradish peroxidase within a graphite paste electrode. The peroxide biosensors based on modified-paste electrodes are characterized by cyclic voltammetry and chronoamperometry. Results on electrochemical sensing of hydrogen peroxide close to the cathode peak potential of potassium ferricyanide and ferrocene monocarboxylic acid are reported. The performance of these peroxide biosensors is discussed and compared to those reported earlier.