Characterization of Poly(brilliant cresyl blue)-Multiwall Carbon Nanotube Composite Film and Its Application in Electrocatalysis

Electrochemically active composite film which contains multi-walled carbon nanotubes (MWCNTs) incorporated with poly(bril-liant cresyl blue) (PBCB) has been prepared on glassy carbon electrode (GCE) and indium tin oxide (ITO) electrode by potentio-dynamic method. The presence of MWCNTs in the composite film (MWCNTs-PBCB) enhances the surface coverage concentration (C) of PBCB by 0.25 nmol cm2 lg1. The surface morphology of various films deposited on ITO has been studied using scanning electron microscopy and atomic force microscopy, which reveals that MWCNTs incorporated with PBCB. The MWCNTs-PBCB composite film exhibits promising enhanced electrocatalytic activity towards the biochemical compound vitamin B9 (folic acid). The electrocatalytic response of folic acid at PBCB, MWCNTs and MWCNTs-PBCB composite films have been studied using cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The sensitivity of MWCNTs-PBCB film towards folic acid (177 lA mM1 cm2) is higher than the values obtained for PBCB (0.75 lA mM1 cm2) and MWCNT films (148 lA mM1 cm2). Similarly, the limit of detection of folic acid at MWCNTs-PBCB film (76 lM) is lower than the other two films. Further, the DPV and selectivity studies reveal that the MWCNTs-PBCB film is efficient for folic acid determination in real sample. VC 2011 The Electrochemical Society. [DOI: 10.1149=1.3556098] All rights reserved. Manuscript submitted November 8, 2010; revised manuscript received January 17, 2011. Published March 9, 2011. Vitamin B9 (folic acid) is a water-soluble vitamin, its deficiency in humans causes various chronic diseases such as leucopoenia