Amperometric phenol biosensor based on covalent immobilization of tyrosinase onto an electrochemically prepared novel copolymer poly (N-3-aminopropyl pyrrole-co-pyrrole) film

An amperometric biosensor has been developed for the quantitative estimation of phenols in aqueous solution. The enzyme, tyrosinase, also called as poly phenol oxidase (PPO), was covalently immobilized on a novel copolymer poly (N-3-aminopropyl pyrrole-co-pyrrole) (PAPCP) film, electrochemically prepared onto an indium-tin-oxide (ITO) coated glass plate. The covalent linkage of enzyme and porous morphology of the polymer film lead to high enzyme loading and an increased lifetime stability of the enzyme electrode. Amperometric response was measured as a function of concentration of phenol, at fixed bias voltage of -0.2 V versus Ag/AgCl in a phosphate buffer (pH 7.2). The electrode gives a wide linear response range of 1.35-222.3, 1.6-118.8, 1.9-257.8 muM, for phenol, catechol and p-cresol, respectively. The response time is <10 s reaching to a 95% steady state current value, and 80% of the enzyme activity is retained for 4 months. (C) 2004 Elsevier B.V. All rights reserved.