Polyaniline/carbon nanofiber and organic charge transfer complex based composite electrode for electroanalytical urea detection

Abstract

A composite electrode based on polyaniline coated modified carbon nanofiber (PANI-mCNF), tetrathiafulvalene-tetracyanoquinodimethane (TTF-TCNQ) and urease (Ur) enzyme was evaluated as biosensor for urea detection. Homogeneous coating of PANI on the surface of mCNF was achieved by oxidative polymerization of anilium ion. Fourier transform infrared (FTIR) spectroscopy and field-emission scanning electron microscopy (FESEM) were used to analyze the structural and morphological characteristics of PANI-mCNF nanocomposite. The biosensor showed excellent electroactivity in neutral and basic medium. A linear response to urea in the concentration range of 0.5-8.4mM with a correlation coefficient of 0.998, good sensitivity (2.84 mu Acm(-2)mM(-1)) and a fast response time (ca. 4 s) was obtained for the biosensor. The minimum detection limit was found to be 3 mu M. The biosensor was stable and showed minimal loss in sensitivity, even after two months of storage. The amalgamation of the PANI and CNF synergistically enhances the performance of the biosensor for electroanalytical detection of urea. (C) 2015 The Japan Society of Applied Physics