title: A graphene oxide-based electrochemical sensor for sensitive determination of 4-nitrophenol.
abstract: A graphene oxide (GO) film coated glassy carbon electrode (GCE) was fabricated for sensitive determination of 4-nitrophenol (4-NP). The GO-based sensor was characterized by scanning electron microscope, atomic force microscopy and electrochemical impedance spectroscopy. The electrochemical behaviors of 4-NP at the GO-film coated GCE were investigated in detail. In 0.1M acetate buffer with a pH of 4.8, 4-NP yields a very sensitive and well-defined reduction peak at the GO-modified GCE. It is found that the GO film exhibits obvious electrocatalytic activity toward the reduction of 4-NP since it not only increases the reduction peak current but also lowers the reduction overpotential. Based on this, an electrochemical method was proposed for the direct determination of 4-NP. Various kinetic parameters such as transfer electron number, transfer proton number and standard heterogeneous rate constant were calculated, and various experimental parameters were also optimized. Under the optimal conditions, the reduction peak current varies linearly with the concentration of 4-NP ranging from 0.1 to 120 μM, and the detection limit is 0.02 μM at the signal noise ratio of 3. Moreover, the fabricated sensor presented high selectivity and long-term stability. This electrochemical sensor was further applied to determine 4-NP in real water samples, and it showed great promise for simple, sensitive, and quantitative detection of 4-NP.
authors.affiliation: Department of Chemistry and Material Science, Hengyang Normal University, Hengyang, 421008 Hunan, PR China. junhua325@yahoo.com.cn
authors.forename: Junhua
authors.initials: J
authors.lastname: Li
authors.forename: Daizhi
authors.initials: D
authors.lastname: Kuang
authors.forename: Yonglan
authors.initials: Y
authors.lastname: Feng
authors.forename: Fuxing
authors.initials: F
authors.lastname: Zhang
authors.forename: Zhifeng
authors.initials: Z
authors.lastname: Xu
authors.forename: Mengqin
authors.initials: M
authors.lastname: Liu
mesh_terms: D055664:Electrochemical Techniques / Q000295:instrumentation / Q000379:methods*; D004566:Electrodes; D004784:Environmental Monitoring / Q000295:instrumentation / Q000379:methods*; D006108:Graphite / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D009596:Nitrophenols / Q000032:analysis*; D012680:Sensitivity and Specificity; D017550:Spectroscopy, Fourier Transform Infrared; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D009596:Nitrophenols; D014874:Water Pollutants, Chemical; D006108:Graphite; C024836:4-nitrophenol