Electrochemical Sensing Technique For Bisphenol A Based On Functional Nanomaterials

In recent years,the security of environmental estrogen has raised widespread concern both nationally and internationally.Bisphenol A is an important polymer material of synthesizing polycarbonate plastic and epoxy resins,which is widely used as food packaging materials,tableware,drink cups,baby bottles,and so on.The studies have shown that bisphenol A has obvious estrogen-like activity.Adverse effects of long-term exposure to bisphenol A include embryo toxicity,teratogenicity and mutagenicity.It is necessary to develop sensitive,convenient and rapid detection techniques for the monitoring and the migration research of bisphenol A.As the vigorous development of nanotechnology,functional nanomaterials have been widely applied in the field of analysis,owing to their unique structural properties and the effects of signal enhancement and catalysis,which provide a new approach for the development of sensors.This thesis mainly focuses on the fabrication of new types of portable or sensitive electrochemical sensors and detection techniques for bisphenol A,based on a variety of functional nanomaterials,and their applications in the rapid detection and the migration research of bisphenol A in the environment or food.The main research contents of the thesis are as follows:In chapter one,a summarization was given on the applications of nano materials in electrochemical sensors.The advancement of bisphenol A analysis was introduced.Then,the selected topic basis and research contents of the thesis were proposed.In chapter two,multi-walled carbon nanotubes/?-cyclodextrin/ferroferric oxide magnetic nanoparticle/ionic liquid composite material was synthesized and characterized.Based on the good conductivity and electrocatalysis of multi-walled carbon nanotubes and Fe3O4 magnetic nanoparticles,and the molecular recognition of?-cyclodextrin to bisphenol A,a kind of miniature electrochemical sensor for bisphenol A was developed.The sensor exhibited electrocatalytic activity and the enhanced response signal to bisphenol A.The concentration of bisphenol A had a good linear relationship with the oxidation peak current in a concentration linear range of 6.0×10-7?1.0×10-5 mol/L,and the detection limit was 1.0×10-8 mol/L.The sensor was applied to the detection of tap water and plastic bottles,and the recoveries were ranged from 69%to 109%.The results showed a good agreement with those obtained using HPLC for the same samples.In chapter three,a new type of electrochemical immunosensor based on gold nanoparticle and horseradish peroxidase-functionalized multi-walled carbon nanotubes(HRP-CNTs)was developed for bisphenol A by indirect competitive immunoassay.Differential pulse voltammetry was applied for the determination of bisphenol A,by using hydrogen peroxide to catalyze the hydroquinone substrate,in the presence of horseradish peroxidase.Under the optimized condition,the concentration linear range of bisphenol A was 0.1?1000 ng/mL and the detection limit was 0.087 ng/mL.The migration behaviors of bisphenol A in metal cans packaging were studied by using this method.The effects of food simulants,heating temperatures and heating times on the migration of bisphenol A were investigated.The results showed that hexane solution was the most suitable food simulant for bisphenol A releases.Using the temperature of 60 ? and heating time of 12 h,the maximum content migration of bisphenol A of 3.8 mg/kg was achieved.This work provided a sensitive and specific method for the rapid detection and evaluation of bisphenol A and the datas for the research of migration behaviors of bisphenol A in food packaging materials.