Study On Electrochemical Sensors Based On Molecular Imprinting And Nanocomposite

Molecularly imprinted polymers （MIPs） are an important synthetic materialsand have wide application, because of its molecular recognition ability to mimicnatural receptor, structure-activity predetermination, specific recognition andpracticability. Nanometer materials modified electrodes and electrochemical sensorshave become the hot topic, for their excellent analytical performances, in the field ofelectrochemistry in recent years. Carbon nanotubes and metallic nanoparticles haverecently attracted great attention in science, especially the applications inelectrochemical sensor field, because of unusual mechanical, electronic and quantumproperties. In this paper, we based on the fine features of molecularly imprintedpolymers and the special effects of nano materials, combination of molecularimprinting technology, nano-materials and electrochemical sensor. Successfullyconstructed some fast response, high sensitivity electrochemical sensors forimprinted matrix as sensitive components. The research work of this paper is asfollows:（1） First, we prepared a multi-walled carbon nanotube load Au/Pt bimetallicnanoparticles modified electrode (Au/PtNPs-MCNTs/GCE), then, molecularlyimprinted polymers are synthesized with aflatoxin B1(AFB1) as the template, ando-phenylenediamine as functional monomer. Sensors are evalued by cyclicvoltammetry, differential pulse voltammetry, electrochemical impedance spectroscopy,UV-vis absorption spectra and scanning electron microscopy. Moreover, Theselectivity of sensors is tested by comparing the response to AFB1with some similarmolecular structures, and it confirms that the sensors have a good sensitivity andselectivity for recognition to AFB1. Under the optimum conditions, A linearrelationship between the sensor response signal and the logarithm of aflatoxin B1concentrations ranging from1×10-10to1×10-5mol L-1was obtained with the linearregression equation I(μA)=-91.22-20.l042lgC(mol L-1), correlation coefficient r=0.9977. The detection limit of the sensor was3.3×10-11mol L-1(S/N=3). The sensorcan be applied to detect the AFB1in fresh rapeseed oil and hogwash oil samplesselectively. （2）The perylene tetracarboxylic acid functionlized multi-walled carbonnanotube was prepared using3,4,9,10-perylene tetracarboxylic acid and acomparative analysis of the morphologies for the multi-walled carbon nanotubeand functionalized multi-walled carbon nanotube was carried out by SEM.Molecularly imprinted polymers are synthesized through electrochemicalpolymerization of p-aminothiophenol (p-ATP) in the presence of Bisphenol Atemplate molecules. Sensors are evalued by cyclic voltammetry, differential pulsevoltammetry. electrochemical impedance spectroscopy and scanning electronmicroscopy. Moreover, The selectivity of sensors is tested by comparing theresponse to BPA with some similar molecular structures. Under the optimumconditions, A linear relationship between the sensor response signal and the negativelogarithm of BPA concentrations ranging from1.0×10-9to5.0×10-6mol L-1wasobtained with the linear regression equation I(μA)=12.7636-1.1717lgC(mol L-1),correlation coefficient r=0.9957. The detection limit of the sensor was0.3nmol L1(S/N=3).（3）molecularly imprinted polymers are synthesized with Cu2+as the template,and o-phenylenediamine as functional monomer. MIPs are tested inthe electrochemical study by cyclic voltammetry, differential pulse voltammetry. Alinear relationship between the sensor response signal and the logarithm of Cu2+concentrations ranging from5.0×10-10to1.0×10-6mol L-1was obtained with thelinear regression equation I(mA)=-0.2801-0.0230lgC(mol L-1)。 correlationcoefficient r=0.9798. The detection limit of the sensor was1.7×10-10mol L-1(S/N=3).