Development And Application Of Multiple Nanocomposites Sensitized Imprinted Electrochemical Sensor

Molecularly imprinted polymer (MIP) which is a kind of polymeric material possessing imprinted cavity size, shape and a certain sequence of functional groups complementary to the target analyte is synthesized using a particular molecule as the template molecule with the process of preassembles, polymerization and washing. The MIP has been applied many fields based on the "memory" function of the MIP which can selectively adsorb the target molecules With the advantage of simple preparation process, good chemical stability, high temperature resistant and specific recognition for the target molecules, the MIP has been approved an alternative selective recognition element for the sensor. Nanomaterials can be used as a tool for signal amplification due to their unique properties of large specific surface area and high surface reactivity. In this paper, the multi-nanomaterials synergistic sensitized imprinted electrochemical sensors were prepared based on the combination of MIP with nanocomposite for detection of the target molecules. A series of imprinted sensors involving magnetic nanotubes, Co-Ni/graphene, graphene/molybdenum disulfide and magnetic graphene/carbon nanotubes as modification material were prepared for detection of drug molecules (kanamycin and caffeic acid) and environmental pollutants (octylphenol and tetrabromobisphenol S). The main content is as follows.1. A novel magnetic imprinted electrochemical sensor was developed based on magnetic multi-walled carbon nanotubes (MWCNTs) for sensitive determination of kanamycin in complicated matrixes. The magnetic molecularly imprinted polymers (MMIP) were prepared based on MWCNTs decorated Fe3O4 nanoparticles using kanamycin as the template molecule and methacrylic acid (MAA) as the functional monomer. The performance of the imprinted sensor was investigated using cyclic voltammetry (CV) and differential pulse voltammetry (DPV) in detail. The sensitivity of the magnetic imprinted electrochemical sensor was improved attributing to the large specific surface area and excellent electrical conductivity of the Fe3O4 nanoparticles and multi-walled carbon nanotubes (MWCNTs). Under the optimum conditions, the response currents of the magnetic imprinted electrochemical sensor exhibited a linear relationship towards the negative logarithm of kanamycin concentrations ranged from 1.0×10-10 mol L-1 to 1.0×10-6 mol L-1 with a detection limit of 2.3×10-11 mol L-1 (signal to noise ratio is 3). The magnetic imprinted electrochemical sensor was applied to detect trace kanamycin in real samples successfully with the recoveries of 92.5-105.3%.2. A novel imprinted electrochemical sensor was prepared based on cobalt-nickel bimetallic nanoparticles by one-step electrodeposited on graphene modified carbon electrode for the sensitive determination of octylphenol. Graphene nanosheets were firstly deposited onto carbon electrode surface by electrochemistry reduction method. Then the cobalt-nickel bimetallic nanoparticles were electrodeposited on the graphene modification electrode surface. The electrochemical behaviors of the imprinted sensor were evaluated with cyclic voltammetry and electrochemical impedance spectroscopy in detail. The results showed that the prepared imprinted sensor displayed high sensitivity toward octylphenol attributing to the synergetic effect derived from the cobalt-nickel bimetallic nanoparticles and graphene. Under the optimized condition, the response currents of the imprinted sensor exhibited a linear relationship toward the negative logarithm of concentrations (C[OP]) ranged from 1.0×10-10 to 1.0×10-7 mol L-1 (R= 0.998) with the detection limit of 3.6×10-11 mol L-1 (S/N=3). The imprinted electrochemical sensor was applied for the determination of octylphenol in plastic bottles, metal bottles and food packaging bags successfully.3. A novel imprinted electrochemical sensor based on molybdenum disulfide hybrid graphene (MoS2-Gr) composite modified carbon electrode was proposed using dopamine as an electropolymerized monomer for sensitive determination of caffeic acid (CA). In this paper, the MoS2-Gr composite was directly electrodeposited on electrode surface to improve the sensitivity and stability of the imprinted electrochemical sensor due to their large surface area and excellent conductivity. The performance of the imprinted electrochemical sensor was investigated by cyclic voltammetry, differential pulse voltammetry and electrochemical impedance spectroscopy in detail. Under the optimum condition, the response currents of the imprinted electrochemical sensor exhibited a linear relationship toward the negative logarithm of caffeic acid concentrations ranged from 1.0×10-10 to 1.0×10-5 mol L-1 (R2= 0.983) with the detection limit of 2.0×10-11 mol L-1 (S/N=3). With high selectivity and sensitivity, the imprinted electrochemical sensor was successfully applied for the determination of caffeic acid in atractylodes macrocephala with recoveries of 88.3-108.4%.4. A novel magnetic molecularly imprinted electrochemical sensor (MMIP/Gr-MWCNTs/CE) was constructed for rapid and sensitive detection of tetrabromobisphenol S (TBBPS) in water samples. The magnetic imprinted sensor based on the magnetic Gr-MWCNTs composite as sensing element modified on surface of electrode was constructed by electropolymerization of dopamine monomer. The sensitivity of the MMIP/Gr-MWCNTs/CE was improved attributing to the large specific surface area and excellent electrical conductivity of the Fe3O4 nanoparticles decorated with Gr-MWCNTs composites. Under the optimum conditions. The MMIP/Gr-MWCNTs/CE was successfully used for detection of TBBPS in drinking water, rain water, lake water and tap water with recoveries of 90.8-91.5,93.8-94.5, 88.4-91.2 and 97.8-98.8%, respectively.