Electrochemical Sensors Based On Functionalized Carbon Nanofibers For Detection Of Bisphenol A In Food

Bisphenol A(BPA)is an important industrial raw material and an endocrine disruptor,which causes harm to the endocrine system,commonly used in water containers and food packaging industry,and the widespread use of BPA has led to its migration to food,beverages and natural environments,making food safety and human health seriously threatened.Therefore,it is necessary to establish a rapid and sensitive detection method to detect the migrated bisphenol A in food packaging,and the electrochemical sensor analysis method has the advantages of high sensitivity,fast analysis and simple equipment.In this project,carbon nanofibers(CNF)were combined with carbon black(CB),gold nanoparticles(AuNPs)and ZIF-8 materials to synthesize two nanocomposites with excellent electrocatalytic performance,and modified them to the electrode surface,based on which two bisphenol A detection methods were established,and the electrochemical reaction mechanism of bisphenol A was systematically explored,and applied to the routine analysis and detection of actual samples.The specific contents are as follows:1.An electrochemical sensor based on functionalized carbon nanofiber/carbon black composite material is used for the detection of bisphenol AIn this study,The modified carbon nanofibers were used as carriers and carbon black to co-modify the glassy carbon electrode,and the electrochemical sensor was constructed,and it was successfully applied to the detection of bisphenol A in actual samples and characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM),and Raman spectroscopy(Raman).The modified electrodes were characterized by electrochemical techniques such as cyclic voltammetry(CV),alternating current impedance spectroscopy(EIS),and differential pulse voltammetry(DPV),and the catalytic rate constant of the electrochemical oxidation reaction of CB/f-CNF/GCE was calculated,the detection conditions such as the amount of drip material and pH were optimized,and an electrochemical sensor for detecting bisphenol A was established under the optimal conditions.The linear range of BPA is 0.4～50 μmol/L,the Limit of Detection(LOD)is 0.059 μmol/L,in addition,the constructed electrochemical sensor has excellent reproducibility and stability,and has good anti-interference ability.This method was used to detect canned yellow peaches and boxed milk with BPA,and the recovery rate was 86.0%-102.6%.This method has also been used to determine BPA migration in canned and packaged milk of canned dace with black bean,and its results are consistent with those obtained by High Performance Liquid Chromatography(HPLC).2.An electrochemical sensor based on zeolite imidazole salt backbone/gold nanoparticle modified carbon nanofiber nanocomposites for the detection of bisphenol AIn this study,a method was developed for ZIF-8/Au@f-CNF materials with high conductivity and enrichment capacity.It was modified onto the GCE surface to establish an electrochemical analysis method for sensitive detection of BPA.By comparing the circulating voltammetry response of the working electrodes of three different components,namely ZIF-8/GCE,Au@f-CNF/GCE and ZIF-8/Au@f-CNF/GCE in potassium ferricyanide solution,it was found that ZIF-8/Au@f-CNF/GCE had the largest current response and the fastest electron transfer rate.It was also calculated that ZIF-8/Au@f-CNF/GCE has the largest electroactive area and the smallest resistance.The electrocatalytic oxidation ability of the above three electrodes on bisphenol A was studied,and the optimal conditions for detecting bisphenol A by the sensor were discussed,and it was concluded that the sensitivity of the sensor was the best when 8 μL of ZIF-8/Au@f-CNF/GCE with a concentration of 3.0 mg mL-1 was injected into the electrolyte phosphate buffer solution at pH 7,and BPA was detected by differential pulse voltammetry.The linear range of this method is 0.1～30 μmol/L,and the detection limit is 0.034 μmol/L(S/N=3),and finally,the sensor was successfully applied to the analysis and detection of bisphenol A in water samples,and the recovery rate ranged from 95.1%to 105.6%.