Amperometric Determination of 4-Nitrophenol at Multi-Walled Carbon Nanotube-Poly(Diphenylamine) Composite Modified Glassy Carbon Electrode

In this work we report the fabrication of multi-walled carbon naontube-poly(diphenylamine) (MWCNT-PDPA) composite film modified glassy carbon electrode (GCE) and its application for the electrochemical reduction of 4-nitrophenol (4-NP). Diphenylamine (DPA) was polymerized on the MWCNT modified GCE by cyclic voltammetry (CV) in 5 M H2SO4. The surface morphology of MWCNT-PDPA was studied using Scanning Electron Microscopy (SEM). The interfacial electron transfer phenomenon at the modified electrode was studied using electrochemical impedance spectroscopy (EIS). 4-NP showed a well defined reduction peak at – 0.71 V (vs. Ag/AgCl electrode) at the MWCNT-PDPA modified GCE. The MWCNT-PDPA composite film showed good electrocatalytic behavior towards the reduction of (4-NP) in pH 7. The MWCNT in MWCNT-PDPA film enhanced the reduction peak current by several times. The peak current increased linearly with 4-NP concentration. The amperometric determination of 4-NP at the composite film modified electrode showed linear range from 8.9 x 10-6 M to 1.43 x 10-3 M. These results show that the proposed composite film modified electrode may be developed for potential application in real sample analysis.