| Bisphenol A(BPA)is a kind of environmental endocrine,also known as endocrine disrupting chemicals,which were widely used in plastics and flame retardants,rubber anti-aging agents,pesticides and other chemical products.Long-term accumulation of BPA in human body may cause endocrine disorders and infertility.It may also increase the risk of cancer and threaten human health.In addition,BPA has been detected in the environment such as air,water,soil,dust,food and drinking water.Therefore,the establishment of a new method for the efficient and accurate detection of trace amounts of BPA in the environment has important significance and application value.Molecular imprinting technology is a kind of molecular recognition technology that simulates antigen-antibody,so that molecularly imprinted polymer has specific recognition performance towards the target,while the electrochemical analysis method has the characteristics of simple operation,accuracy and high efficiency.Combining the recognition performance of molecularly imprinted polymers with the sensitivity of electrochemical analysis methods,the constructed electrochemical sensor has the advantages of high selectivity and high sensitivity.Currently,molecularly imprinted electrochemical sensors are used to detect various trace pollutants in the environment,and have become one of the research hotspots.Therefore,this type of sensor has certain potential and value for the detection of BPA in the environment.In this paper,three kinds of new molecularly imprinted polymers were prepared using multi-walled carbon nanotubes,quantum dots and graphene as sensitizers.In conjunction with electrochemical workstations,three new types of BPA imprinted electrochemical sensors have been constructed.The work is mainly carried out from three aspects.The specific contents are as follows:(1)Design,preparation and performance study of BPA imprinted electrochemical sensor based on bifunctional multi-walled carbon nanotubes:First,molecular simulation technology was applied to calculate template molecule BPA and functional monomer APTES,and analyze its spatial structure.Then,the multi-walled carbon nanotubes were modified by amination,and molecularly imprinted polymers were synthesized on this basis,and they were modified on the surface of glassy carbon electrodes to prepare molecular imprinted electrochemical sensors.Under optimal conditions,the sensor has good selectivity,repeatability and stability,with RSDs of4.93%and 5.44%,respectively;the detection range is 10-10?10-5 mol L-1,and the detection limit is 1.57×10-11 mol L-1.Finally,the sensor was applied to the analysis and detection of BPA in actual samples(plastic bottles,food boxes,mobile phone casings),and the recovery rate ranged from 92.93%to 104.42%,and the relative standard deviation ranged from 2.91%to 6.86%.(2)Preparation and performance study of BPA imprinted electrochemical sensor based on quantum dots-multi-walled carbon nanotubes:cadmium telluride quantum dots were modified through carboxylation and grafted with aminated multi-walled carbon nanotubes by dehydration condensation,in order to form QDs-MWCNTs composite to improve the conductivity and sensitivity.On this basis,APTES was used as a functional monomer to synthesize a molecularly imprinted polymer.The composites were dropped on the surface of the glassy carbon electrode to prepare a BPA sensor.The successful recombination of quantum dots allows the electrode to convert a small concentration difference into a large current response change.The prepared sensor has good selectivity,together with high stability and repeatability,of which RSDs were 5.17%and 0.43%,respectively.In addition,the sensor also exhibits a linear relationship within the concentration range of 0.05?50 nmol L-1,and the detection limit is 0.015 nmol L-1.Thus,the BPA content in three different water samples(tap water,campus river water and drinking water)was tested.The recovery rate ranges from 87.08%to 102.57%,and the RSD ranges from 3.10%to 5.83%.(3)Preparation and performance study of BPA imprinted electrochemical sensor based on titanium nitride-reduced graphene oxide:using Ti N-r GO as the material for electrochemical sensitization,silica as the carrier,and polypyrrole as the functional monomer,BPA as a template to synthesize a polymer with a core-shell structure.Ti N--RGO composite material improves the efficiency of electron transmission,which is the premise of efficient detection.Through a series of characterization performance tests,the sensor has excellent selectivity,repeatability and stability,with RSDs of 0.02%and 1.90%,respectively,which provides a guarantee for accurate detection.The sensor can maintain a regular linear response in the detection range of 0.5?100 nmol L-1 and the detection limit is 0.19 nmol L-1.Finally,the sensor was used for detection in actual samples.Finally,the sensor was used to detect three actual samples(milk,plastic bottle and mobile phone case)with recoveries ranging from 94.02%to 112.00%and relative standard deviations ranging from 2.98%to 8.87%.In summary,this paper studied the preparation of three novel molecularly imprinted electrochemical sensors.Also,their electrochemical performance was discussed,together with their application in detecting BPA in the environment.It provides the feasible idea and method for the detection and analysis of environmental hormone in the future environment. |
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