Electrochemically prepared polypyrrole-2-carboxylic acid films: synthesis protocols and studies on biosensors

Instituto de Fsica de S¼o Carlos, Universidade de S¼o Paulo, Av. Trabalhador S¼o-carlense 400, S¼o Carlos, SP, postcode 369,13560-970, Brazil*e-mail: gdebora@ifsc.usp.brReceived: October 17, 2012Accepted: December 4, 2012Published online: February 22, 2013AbstractThe process for obtaining polypyrrole-2-carboxylic acid (PPY-2-COOH) films in acetonitrile was investigated usingcyclic voltammetry, electrochemical quartz crystal microgravimetry (EQCM), and infrared spectroscopy (FTIR).Different potential ranges were applied during cyclic voltammetry experiments with the aim of obtaining films with-out and with the presence of controlled amounts of water added in acetonitrile. The FTIR spectra of the films haveevidenced that cations and anions from the electrolyte solution were incorporated into the PPY-2-COOH structure,with a preferential adsorption of cations. After chemically immobilizing polyphenoloxidase (tyrosinase, PPO), PPY-2-COOH/PPO films were build for amperometric detection of catechol, establishing a linear limit of concentrationsranging from 5.010