Electrochemical sensors based on functionalized ormosil-modified electrodes—role of ruthenium and palladium on the electrocatalysis of NADH and ascorbic acid

We report here in the preparation of seven different types of functionalized ormosil-modified electrodes derived from 3-glycidoxypropyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-aminopropyltrimethoxysilane in acidic medium in the presence of: (1) tris(2,2′-bipyridyl)ruthenium chloride; (2) palladium chloride; (3) both tris(2,2′-bipyridyl)ruthenium chloride and palladium chloride; (4) ferrocene monocarboxylic acid; (5) tris(2,2′-bipyridyl)ruthenium chloride and ferrocene Monocarboxylic acid; (6) palladium chloride and ferrocene monocarboxylic acid; (7) tris(2,2′-bipyridyl)ruthenium chloride, palladium chloride and ferrocene monocarboxylic. The electrocatalytic oxidation of reduced nicotinamide adenine dinuleotide (NADH) and ascorbic acid is examined on the surface of these functionalized ormosil-modified electrodes. The results based on cyclic voltammetry and amperometric measurements are reported. The results suggest: (a) excellent reversible redox electrochemistry of ferrocene monocarboxylic acid, when ruthenium and palladium both are incorporated within ormosil, as compared to that of redox electrochemistry of ferrocene monocarboxylic acid observed in homogeneous solution; (b) the presence of ruthenium facilitate the electrocatalytic efficiency of ormosil-modified electrode; (c) relatively, better selective oxidation of NADH on the surface of functionalized ormosil-modified electrode made in the presence of both palladium and ruthenium derivatives. The performances of these modified electrodes are reported in this communication.