Recognition and Electrochemical Determination of Environmental Contaminants Nitrophenol by Cyclodextrin Homologous Functionalized Graphene Modified Electrodes

The determination of Nitrophenol (NP) isomers, one type of serious environmental contaminants, is of great importance for environmental control. Herein, a novel electrochemically modified glassy carbon electrodes (CDs/CRG/GCE) is developed for determination of NP isomers using different cyclodextrins (alpha-,beta- and gamma-CD) in combination with chemically reduced graphene (CRG). The recognition mechanism of different cyclodextrins (CDs) for NP isomers is systematically studied. Interestingly enough, the cavity size of CDs plays an important role in the recognition of NP isomers. The alpha-CD/CRG/GCE and gamma-CD/CRG/GCE display the best response to p-NP and o-NP, respectively. All three types of CDs modified electrodes show the similar effect on m-NP. Attributed to the synergistic effect of the specific recognition property of CDs and the excellent electronic property of CRG, the CDs/CRG/GCE exhibits outstanding supramolecular recognition and sensitive electrochemical response to NP isomers compared with that of CRG/GCE. The reductive peak current of p-NP at a-CD/CRG/GCE is linearly dependent on the concentration in the range from 1.0 x 10(-7) to 1.5 x 10(-4) mol/L with a low detection limit of 3.3 x 10(-8) mol/L. The present work offers a new way to broaden the analytical applications of graphene-based materials for isomer analysis.