Development Of Electrochemical Immunosensing Assay For Bisphenol A In Food

Bisphenol A(BPA)is a kind of plasticizer and also an environmental estrogen.It can be transported to food from packaging materials,and then ingested into the human body.Long-term accumulation of BPA can cause health damage.Therefore,it is of great significance to establish an effective method to determine BPA in foods.In this study,two kinds of BPA complete antigens were prepared.Two BPA polyclonal antibodies were produced by animal immunization.Enzyme-linked immunosorbent assay(ELISA)was used to screen antiserum with better specific recognition ability for BPA.and the antiserum was purified to obtain the BPA antibody for the establishment of immunosensing method.The BPA antibody was immobilized on the electrode,and the BPA in the sample was captured by the specific binding force between antigen and antibody.A cyclic voltammetry is used to detect the redox electrochemical signal produced by the system.Nano-gold was modified by electrodeposition on the electrode surface as a signal enhancement system to increase electrode sensitivity.The reaction conditions that affect the detection result are optimized.The working conditions of the optimized electrochemical immunosensor were as follows:the optimal concentration of antibody was 100 p,g/mL,the pH of antibody buffer was 7.4,the optimal concentration of enzyme-labeled antigen was 10?g/mL,and the optimal reaction time of enzyme-labeled antigen was 1 h.The solvent of the working electrolyte is pH 7.4 phosphate buffered saline,and the concentration of the oxidant hydrogen peroxide in the working electrolyte is 143.65 mg/mL.The detection limit of this method in PBS is 4.00 ?g/L.The established method was applied to the detection of BPA in food samples(pure water,canned yellow peaches,canned lobster fish,and canned meat for lunch),and the the method of eliminating the effect of the sample matrix is optimized.The detection limit of BPA was 8.00 ?g/kg in canned samples and 4.00 ?g/L in water.The recovery rates of BPA were between 79.10 and 115.88%,and the coefficient of variations were between 0.22 and 15.46%.The electrochemical immunosensor method was validated by high performance liquid chromatography.The consistency of the two methods was 0.9717,which proved that the electrochemical immunosensor method has good accuracy and high precision.This method can be used to effectively detect BPA in canned foods and water samples.