Development of a potentiometric urea biosensor based on copolymer poly( N-3-aminopropyl pyrrole-co-pyrrole) film

Abstract

A novel potentiometric biosensor has been developed for the quantitative estimation of urea in aqueous solution. The enzyme, urease (Urs), was covalently immobilized on a novel conducting copolymer poly( N-3-aminopropyl pyrrole-co-pyrrole) 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. The biosensor has been characterized by UV–Vis and infrared spectroscopy. Photometeric and potentiometric studies have been conducted on these enzyme immobilized polymer films. Potentiometric response was measured as a function of urea concentration in Tris–HCl buffer (pH 7.0). The electrode showed a linear response range from 6.3 × 10 −6 to 4.07 × 10 −4 M urea. The response time is about 25–50 s reaching to a 95% steady-state potential value, and 80% of the enzyme activity is retained for about 2 months.