Very sensitive differential pulse adsorptive stripping voltammetric determination of 4-nitrophenol at poly (diphenylamine)/multi-walled carbon nanotube-β-cyclodextrin-modified glassy carbon electrode

In this work, a glassy carbon electrode (GCE) modified with poly (diphenylamine)/multi-walled carbon nanotubes-beta-cyclodextrin (PDPA/MWCNT-beta-CD) film was constructed and used for the determination of 4-nitrophenol (4-NP). Diphenylamine was successfully electropolymerised onto MWCNT-beta-CD-modified GCE by cyclic voltammetry in monomer solution and 5molL(-1) H2SO4. The surface morphology of PDPA/MWCNT-beta-CD film was characterised using scanning electron microscopy and electrochemical impedance spectroscopy. After adsorption of 4-NP on PDPA/MWCNT-beta-CD at 0.2V for 150s, it showed a well-defined reduction peak in phosphate buffer solution at pH=7. The PDPA/MWCNT-beta-CD film enhanced the reduction peak current due to the complex formation between beta-CD and 4-NP, presence of conductive polymer film as electron transfer mediator and also ability of MWCNTs for strong adsorptive and catalytic effect. Peak current increased linearly with 4-NP concentration in the range of 0.1 to 13.9 mu gL(-1). The detection limit was obtained as 0.02 mu gL(-1), which is better than other reported detection limits for the determination of 4-NP. The results showed that modified electrode has good sensitivity and selectivity. This sensor was used for the determination of 4-NP in water samples.