Molecularly Imprinted Electrochemical Sensors Based On Graphene And Their Applications In The Evironmental Analysis

To construct fast, efficient and sensitivity electrochemical sensors has become a development direction of environmental contaminant determination. This paper combined the techniques of molecular imprinting and electrochemical sensing. Three imprinted electrochemical sensors based on graphene were constructed for the detection of 1-aminonaphthalene, diphenylamine and ofloxacin. The main work are as follows:(1) A novel composite of a cyclodextrin-functionalized graphene nanosheet and molecularly imprinted poly(vinylferrocene)(GN/CD-MIPVF) was prepared. The GN/CD-MIPVF composite was obtained with GN/CD as supporting material, 1-naphthylamine(1-NA) as template, vinylferrocene as functional monomer and ethylene glycol dimethacrylate (EGDMA) as cross-linking agent, and it was applied to construct an electrochemical sensor for 1-NA. The GN/CD-MIPVF composite was characterized using Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, thermal gravimetric analysis (TGA), and scanning electron microscopy (SEM). The electrochemical behaviour of the GN/CD-MIPVF sensor was evaluated by differential pulse voltammetry. Under optimal conditions, the GN/CD-MIPVF sensor had a wide linear range over 1-NA concentrations from 0.3 to 100.0 μM with a detection limit of 0.1 μM (S/N=3). The GN/CD-MIPVF sensor shows high sensitivity, and was satisfactorily used for the determination of 1-NA in environmental water samples.(2) The graphene/RuNPs (GR-Ru) composite was prepared using NaBH4 reduction method. Meanwhile, the molecularly imprinted SiO2 (MIS) material was synthesized by sol-gel method using diphenylamine (DPA) as template molecule, phenyl trimethoxysilane as functional monomer, tetramethoxysilane as crosslinking agent. The GR-Ru was dropped onto the surface of glassy carbon electrode (GCE), then MIS was dropped onto GR-Ru/GCE to prepare DPA electrochemical sensor. The electrochemical behaviour of GR-Ru/MIS modified electrode was investigated by differential pulse voltammetry, chronoamperometry and cyclic voltammetry. The DPV current response of GR-Ru/MIS sensor was 3.1 times than non-imprinted polymers. The GR-Ru/MIS sensor had a wide linear range over DPA concentration from 0.05 to 70.0 μM with a detection limit of 0.02 μM (S/N=3).(3) A novel composite of a graphene-rhodium nanoparticles and molecularly imprinted polymers (GN/Rh-MIP) was synthesized using GN/Rh as support material, ofloxacin (OF) as template molecule, ferrocenylmethyl methacrylate as a monomer, (3,3’-(1’,4’-butane)-bis-l-ethenyl-methylimidazolium hexafluorophosphate as crosslinking agent. The GN/Rh-MIP composite was characterized using Scanning electron microscopy, Fourier transform infrared spectroscopy, Thermal gravimetric analysis, Transmission electron microscope and Raman spectroscopy. The electrochemical behaviour of GN/Rh-MIP sensor was investigated by differential pulse voltammetry and cyclic voltammetry. The GN/Rh-MIP sensor exhibited a high adsorption and good selectivity toward OF. The GN/Rh-MIP sensor had a wide linear range over OF concentration from 0.2 to 120.0 μM with a detection limit of 0.06 μM (S/N=3). The GN/Rh-MIP imprinted electrochemical sensor showed high sensitivity and rapid response for OF. It provides a novel method for detecting OF. This method should be expected to be used in environment and pharmaceutical field.