Study Of Electrochemical Sensor Based On Functionalized Graphene And Molecularly Imprinted Technology

In this thesis, Graphene nanocomposites and molecularly imprinted polymers(MIP) were synthesized. These graphene nanocomposites and MIP were employed to modify electrodes to construct highly sensitive electrochemical sensors for the detection of phenolic compounds. The main contents include the following two parts:1 ? Molecularly imprinted polymer(MIP) of 4-chlorophenol(4-CP) was synthesized and combined with poly(diallyldimethylammonium chloride)(PDDA)-functionalized graphene(PDDA-G) to develop an electrochemical sensor for selective determination of 4-CP. The chemical structures of the imprinted films were analyzed using Fourier transform infrared(FTIR) spectroscopy. The morphology and interfacial behavior of MIP and PDDA-G modified glassy carbon electrodes(GCEs) were investigated by scanning electron microscopic(SEM) and electrochemical impedance spectroscopic(EIS) techniques, respectively. The obtained MIP/PDDA-G/GCE showed high sensing performance towards 4-CP. Under optimized conditions, the sensor showed a linear response to the concentration of 4-CP in a wide range from 0.8 to 100 ?mol·L-1 with a detection limit(3S/N) of 0.3 ?mol·L-1. Moreover, the imprinted sensor exhibited excellent specific recognition ability to 4-CP which could avoid the interference of other structurally similar phenolic compounds. The developed sensor was successfully applied to the detection of 4-CP in real-life water samples.2?Electrochemical sensors based on H-GNs and molecularly imprinted polymer are developed for sensitive and selective detection of 4-aminophenol. The 4-aminophenol molecularly imprinted polymer was prepared successfully by using methacrylic acid(MAA) as functional monomer and ethylene glycol dimethaerylate(EGDMA) as crosslinker. The MIP were characterized by infrared spectroscopy and scanning electron microscopy. H-GNs were synthesized through the ?-? interactions. H-GNs, serving as the loding platform for MIP immobilization, have intrinsic peroxidase-like activity, which can catalyze the reaction of 4-aminophenol. As an electrochemical sensor, the MIP/H-GNs/GCE exhibited strong catalytic activity toward the reduction of 4-aminophenol which was demonstrated by cyclic voltammetry(CV). Under optimized conditions, the sensor showed a linear response to the concentration of 4-aminophenol in a range from 0.3 to 25 ?mol·L-1(R2=0.997)with a detection limit(3S/N) of 0.06 ?mol·L-1. Moreover, the imprinted sensor exhibited excellent specific recognition ability to 4-aminophenol which could avoid the interference of other structurally similar phenolic compounds. This proposed sensor is satisfactorily applied to determine4-aminophenol in real-life water samples.