Immobilization of GOD on Ppy–PVS Composite Film for Determination of Glucose: A Comparative Study of Phosphate and Acetate Buffers

Abstract

The Polypyrrole-polyvinylsulphonate-glucose oxidase (Ppy–PVS–GOD) biosensor for determination of glucose has been described in the present investigation. The enzyme, glucose oxidase (GOD) was immobilized by crosslinking via glutaraldehyde on a polypyrrole–polyvinyl sulphonate (Ppy–PVS) composite film. The Ppy–PVS film was electrochemically synthesized on indium-tin-oxide (ITO)–coated glass plate. The synthesized composite films were characterized using galvanostatic electrochemical technique, electrical conductivity, UV-Visible spectroscopy, Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). The crosslinking of enzyme and porous morphology of the polymer film leads to high enzyme loading and an increase in lifetime, stability, and fast response time of the enzyme electrode. Characterization of resulting amperometric biosensor for the estimation of glucose has been experimentally determined in terms of linear response range, optimum pH, applied potential, and shelf-life. These Ppy–PVS–GOD electrodes can be used for glucose estimation from 1 to 50 mM and have a shelf-life of about 5–6 weeks at 4°C. The sensitivity of Ppy–PVS–GOD electrode in phosphate and acetate buffer has been studied. It was found that the phosphate buffer gives fast response as compared to acetate buffer in amperometric measurements.