Study On Sensitive Electrochemical Detection Method Based On Metal Nanocomposites Catalytic For Bisphenol A In Food

Bisphenol A（BPA）is an industrially synthesized organic compound that is widely used in food packaging materials such as can coatings,baby bottles and plastic water bottles.A large number of studies have shown that BPA,as an endocrine disruptor,can cause harm to human health,causing breast cancer,diabetes and other diseases.Therefore,there is an urgent need to find a fast,simple and accurate detection method for BPA.Traditional detection methods such as chromatography and immunoassay are complicated and costly.Electrochemical sensors have been widely used for the detection of biochemical substances due to the advantages of high sensitivity,simple operation and fast analysis speed.In this paper,electrochemical sensors were constructed based on metal nanocomposites combined with molecular imprinting technology to realize the rapid and highly sensitive detection for BPA in food.The main studies and results are as follows.（1）Development of sensitive electrochemical sensor based on chitosan/MWCNTs-Au Pt Pd nanocomposites for detection of bisphenol AAn electrochemical sensor based on Au Pt Pd trimetallic nanoparticles functionalized multi-walled carbon nanotubes coupled with chitosan modified glassy carbon electrode（GCE/CS/MWCNTs-Au Pt Pd）was proposed for the sensitive detection of bisphenol A（BPA）.Au Pt Pd trimetallic nanoparticles were first assembled on MWCNTs to obtain MWCNTs-Au Pt Pd nanocomposites.Then the MWCNTs-Au Pt Pd was further dispersed on the surface of chitosan modified electrode surface to fabricate the GCE/CS/MWCNTs-Au Pt Pd sensor.Due to the superior catalytic properties of MWCNTs-Au Pt Pd and the good film formation of chitosan,the constructed sensor displayed good performances for BPA detection.The structural morphology of CS/MWCNTs-Au Pt Pd was characterized by many methods,such as scanning electron microscope（SEM）,transmission electron microscope（TEM）and ultraviolet and visible spectroscopy（UV-vis）.Under the optimal conditions,the designed sensor showed a linear range from 0.05 to 100μM for BPA detecting with a low detection limit of 1.4 n M.The designed sensor was further used to realize the determination of BPA in real samples and the recoveries ranged from 94.4%to 103.6%.（2）Bisphenol A detection based on nano gold-doped molecular imprinting electrochemical sensor with enhanced sensitivityA facile electrochemical sensor based on nano gold-doped molecularly imprinted polymer（MIP）was proposed to realize the selective detection of bisphenol A（BPA）with enhanced sensitivity.Initially,gold-doped polymer film was constructed on the surface of Au NPs modified electrode by electropolymerizing BPA and p-aminobenzoic acid（PABA）with in situ gold reduction.Subsequently,GCE/Au/Au@MIP was prepared by extracting template from the polymer film.Then the MIP could rebind with the template molecules to achieve specific detection of BPA.The nano gold-doped MIP increased the effective surface area and promoted conductivity when BPA was oxidized in the imprinted cavities,which improved the determination sensitivity.The constructed sensor was characterized by cyclic voltammetry（CV）,electrochemical impedance spectroscopy（EIS）,SEM and energy dispersive spectrometry（EDS）.Under optimal conditions,the prepared sensor displayed a linear range from 0.5 to 100μM for BPA detection with a detection limit of 52 n M.The designed sensor was further used to detect BPA in food samples,obtaining satisfactory recoveries from 96.7%to 107.6%.（3）Octahedral Cu₂O/Au nanocomposites coordinating molecular imprinting to enhance performance of the electrochemical sensor for bisphenol AA novel electrochemical sensor based on octahedral Cu₂O/Au nanocomposites in collaboration with molecularly imprinted polymer（MIP）was constructed for the specific and highly sensitive detection of BPA.Firstly,Au NPs were electrodeposited on the surface of octahedral Cu₂O modified electrode and the polymer film was formed by electropolymerizing of pyrrole with template molecule on the surface of Cu₂O/Au nanocomposites modified electrode.Then the imprinted cavities were obtained by removing BPA from the MIP film to fabricate the MIP-based sensor.Cu₂O/Au nanocomposites had a large specific surface area and good catalytic performance,and the specificity and sensitivity of the sensor were enhanced owing to the MIP cooperated with the nanocomposites.The GCE/Cu₂O/Au/MIP was characterized by SEM,EIS and CV,and the experimental conditions were optimized.Compared with GCE/Au/MIP and GCE/MIP,the fabricated sensor had a wider detection range and lower detection limit for BPA detection.Under optimal conditions,the linear range of BPA detection was 0.2～80μM,and the detection limit was 29 n M.The designed sensor was applied to the detection of BPA in actual samples,and the recovery rate was 95.5%～103.3%,indicating that the sensor was applicability in practical detection.