A novel ferrocene encapsulated palladium-linked ormosil-based electrocatalytic dopamine biosensor

A novel finding on the development of electrocatalytic biosensor for dopami ne is reported. The new electrocatalytic dopamine biosensor is developed us ing ferrocene encapsulated palladium (Pd)-linked organically-modified sol-g el glass (ormosil). The alkoxy precursors used for the preparation of new o rmosil-based electrocatalytic biosensor are palladium-linked glycidoxypropy ltrimethoxysilane and trimethoxysilane. The optimum concentrations of these precursors are added in aqueous solution of ferrocene monocarboxylic acid and HCl followed by gelation for 30 h at 25 degreesC to form ormosil. The f errocene encapsulated ormosil is characterized based on cyclic voltammetric measurements. The CV results shows peak separation of 57-59 mV and a linea r relation between peak current and square root of scan rate suggesting wel l behaved reversible electrochemistry of ormosil encapsulated ferrocene. Th e CV results and the detection of ferrocene in working medium shows that fe rrocene is not leached out of ormosil matrix. The tyrosinase is immobilized within polyvinyl alcohol over the ferrocene encapsulated new ormosil and f inally mounted using nucleopore membrane. The electrocatalytic response of immobilized tyrosinase over new ormosil is observed and the results are rep orted. The performance, stability, and reproducibility of new ormosil-based dopamine biosensor are reported. (C) 2001 Elsevier Science B.V. All rights reserved.