Polypyrrole microfibres synthesized with Quillaja Saponin for sensing of catechol

The polypyrrole microfibres were synthesized potentiodynamically on platinum electrodes using the natural surfactant Quillaja Saponin. Employing amperometric and impedimetric techniques, the suitability of these electrodes as biosensors for catechol is investigated, in the presence of the enzyme Tyrosinase. The amperometric measurements reveal the linear concentration regime from 1 mu M to 400 mu M while the upper limit of detection using impedance studies is estimated as 200 mu M. The fitting of the Nyquist and Bode' plots is carried to deduce the system parameters. The low magnitude of Michaelis-Menten constant (103 mu M) suggests the high activity of the Tyrosinase enzyme. The temporal stability of the electrode has been estimated and the effect of interference from phenol, resorcinol and ascorbic acid is also investigated. (C) 2012 Elsevier B.V. All rights reserved.