Study On Novel Nanomaterial Modiifed Imprinted Electrochemical Sensor

Recently, electrochemical sensors possessing the merits of fast response speed, cheapinstrument, simple operation, time-saving, high sensitivity, has been utilized in real-timedetection in the field of medical, biological and environmental analysis. Molecularlyimprinted polymers (MIPs) are cross-linked polymers with specific recognition propertyfor the template molecule. Modified the MIPs and nano-materials can improveselectivity and sensitivity of the electrochemical sensor, as well as lower the detectionlimit. In this paper, the sensors were fabricated with the bare carbon electrode whichwas modified with various imprinted film and nano-materials as the work electrode.Finally the modified electrode can be used to detect the environmental pollutants. Themain researchs were as follow:1. A novel graphene modified molecularly imprinted electrochemical sensor wasfabricated with electropolymerization method using3,3’,5,5’-tetrabromobisphenol S(TBBPS) as the template molecule and polypyrrole as the monomer. Piror to imprinted,the carbon electrode was electrodeposited with the aromatic diazonium salt which wasused to adsorb graphene oxide. Then, the graphene oxide modified on the carbonelectrode was reduced to graphene with electrochemical reduction. The graphenemodified molecularly imprinted electrochemical sensor was characterized by scanningelectron microscopy (SEM), cyclic voltammetry (CV) and differential pulsevoltammetry (DPV). The results indicated that the graphene was modified on the carbonelectrode successfully and the graphene modified imprinted electrochemical sensorexhibited excellent selectivity toward the template molecule TBBPS. The adsorptionexperiment showed that a linear relationship was obtained between the responsecurrents and the negative logarithm of the TBBPS concentrates range of5.0×105～1.0×108mol L1with the detection limit of3.3×109mol L1(S/N=3). The graphenemodified imprinted electrochemical sensor was applied to detect the TBBPS in rain, tapwater and mineral water samples successfully.2. A highly sensitive and selective imprinted electrochemical sensor based on Agnanoparticles and graphene modified carbon electrode with covalent anchoring andelectrochemical reduction was prepared for the determination of bisphenol A (BPA) inaqueous solution. The imprinting film was fabricated by electrodepositing pyrrole in thepresence of BPA onto the graphene and Ag nanoparticles modified electrode surface.The morphologies of the electrodes were characterized with scanning electronmicroscopy. The electrochemical performance of the imprinted electrochemical sensorwas investigated with cyclic voltammetry and differential pulse voltammetry techniquesin detail. The response currents of the imprinted electrochemical sensor exhibit a linearrelationship toward the negative logarithm of the concentrations of BPA ranging of1.0 ×1011~1.0×108mol L1. The detection limit of the imprinted electrochemicalsensor toward BPA is calculated as3.2×1012mol L1(S/N=3). The imprintedelectrochemical sensor was successfully applied to detect BPA in real plastic sampleswith good recoveries ranging of93.3%~103.0%.3. A fast and easy method for the fabrication of an imprinted electrochemicalsensor based on graphene/carbon nanotubes composites modified carbon electrode wasdeveloped for tetrabromobisphenolA detection. The imprinted film was prepared byone-step electro deposition with pyrrole as the monomer and tetrabromobisphenol A asthe template molecule. Compared with the only graphene and carbon nanotubesmodified electrode, the graphene/carbon nanotubes modified electrode exhibitedoutstanding increment sensitivity. The imprinted electrochemical sensor based ongraphene/carbon nanotubes was used for the determination of tetrabromobisphenol Awith differential pulse voltammeters under the optimum conditions and a good linearrelationship between response peak current and the concentration oftetrabromobisphenol A was obtained in the concentration range from1.0×1011~1.0×108mol L1with a detection limit of3.7×1012mol L1(S/N=3). The proposedimprinted electrochemical sensor showed a good selective affinity fortetrabromobisphenol A compared with similar molecules and good reproducibility andstability. The graphene/carbon nanotubes modified imprinted electrochemical sensorwas used to the determination of tetrabromobisphenol A in fish samples successfully.4. A novel molecularly imprinted polymer (MIP) sensor coupled with molecularlyimprinted magnetic solid-phase microextraction (MMISPE) was developed for selectiveand sensitive determination of tetrabromobisphenol A (TBBPA) in complex matrixes.The magnetic molecularly imprinted polymer (MMIP) was synthesized as solid phaseextraction (SPE) sorbet to extract TBBPA from complex matrixes and thegraphene/carbon nanotube composite (Gr/CNT) as sensing element to improve thesensitivity of the imprinted sensor. The electrochemical performances of imprintedsensor were investigated by cyclic voltammetry and differential pulse voltammetry.Under the optimized experimental conditions, this combination achieved the stringentlimit relationship with the detection limit of1.8×1013mol L1at S/N=3, which isalmost17-fold than that of the imprinted sensor. The combination detection system wasapplied to detect TBBPA in complex samples successfully.