Amperometric urea biosensor based on platinum electrode modified with a nanocomposite film

A novel amperometric biosensor for the detection of urea was prepared by immobilizing urease on a modified electrode of nanocomposite film/platinum substrate. The nanocomposite film was obtained by electrochemical co‐polymerization of the corresponding monomers in the presence of functionalized carbon nanotubes and different additives. These nanocomposites were used as conducting films for amperometric urea sensing after covalent immobilization of urease onto nanocomposite‐coated electrodes. The electrochemical performance of the modified electrode was studied by cyclic voltammetry, chronoamperometry and scanning electron microscopy. The immobilized urease on the nanocomposite film surface exhibited an excellent electrocatalytic response toward the reduction of urea. Amperometric response was measured as a function of urea concentration at a fixed potential, in this case, the open circuit potential. The obtained sensor showed rapid response and good reversibility. The response time was less than 10 s, whereas the reversible time was approximately 5 to 15 s. The enzymatic nanostructured electrode exhibited high sensitivity, a wide linear range and low detection limit for the electrochemical detection of urea. Copyright © 2012 John Wiley & Sons, Ltd.