Electrochemical simultaneous determination of hydroquinone and p-nitrophenol based on host-guest molecular recognition capability of dual β-cyclodextrin functionalized Au@graphene nanohybrids

Cyclodextrins (CDs) are extensively used in nanoscale electrochemical devices because of their outstanding host-guest molecular recognition capability. In this study, uniform, monodispersed 4.5 nm gold nanoparticles (Au NPs) were anchored onto carboxylic graphene nanosheets (CGS) using a green approach performed under mild conditions and without using any additional surfactant or reductant. A dual beta-CD (SH/NH2-beta-CD)-functionalized Au@CGS (beta-CD-Au@CGS) nanohybrid was successfully fabricated by subsequent conjugation of beta-CD with the aid of thiol and carboxyl groups. Simultaneous electrochemical determination of hydroquinone (HQ) and p-nitrophenol (PNP) using a beta-CD-Au@CGS nanohybrid-modified glassy carbon electrode was conducted. Differential pulse voltammetry was used to simultaneously quantify HQ and PNP within the concentration range of 0.01-200 mu M under optimal conditions. The limits of quantification for both HQ and PNP were 0.01 mu M. The detection limits (S/N = 3) of the beta-CD-Au@CGS-nanohybrid electrode for HQ and PNP were 6.5 and 3.8 nM, respectively. Interference study results demonstrated that several similar aromatic compounds did not interfere during the determination of HQ and PNP, indicating the high selectivity of the beta-CD-Au@CGS-nanohybrid electrode. The low detection limit and high selectivity of the proposed electrochemical sensor were caused by the high surface area, the excellent conductivity, and the high host-guest molecular recognition capability of the beta-CD-Au@CGS nanohybrids. (C) 2014 Elsevier B.V. All rights reserved.