Research On Food Safety Detection Based On Surface Molecular Imprinting Technology Modified By Nanoparticles

With the continuous improvement of people’s living standards and the continuous improvement of their quality of life,people are paying more and more attention to food safety issues.At the same time,driven by huge interests,businesses of various processed foods have added some substances that should not have been in the food or added substances that are harmful to human health when excessively used,resulting in a very serious food safety problem.In daily life,there is an urgent need for an efficient,convenient and highly accurate,reusable sensor to be used in the detection of food safety.Therefore,it is very important to prepare a method that can detect food safety efficiently and quickly.necessary.This article is based on the characteristics of molecular imprinting technology that has good stability and can specifically identify target molecules,combined with the convenience and quickness of electrochemical sensing and simple operation.Nanomaterials are used to support the surface of different electrodes to make the prepared molecularly imprinted polymer membranes more sensitive,and the prepared sensors are tested for related electrochemical characteristics and actual sample analysis.The specific work is as follows:1.Using metronidazole（MNZ）as template molecule,o-phenylenediamine as functional monomer,and nano-gold（AuNPs）as modified electrode material,molecularly imprinted polymerization was prepared on the surface of glassy carbon electrode（GCE）by electropolymerization Membrane,successfully constructed a molecularly imprinted sensor for the detection of metronidazole.Cyclic voltammetry（CV）was used to analyze the catalytic effect of gold nanoparticles.After optimizing the experimental conditions,the electrochemical behavior of the sensor in different concentrations of metronidazole was used to evaluate the characteristics of the sensor using differential voltammetry（DPV）.By fitting the linear relationship,the detection limit of the sensor is 3.25×10^-12mol/L（S/N=3）,and the correlation coefficient is R2=0.99438,and it has good stability and anti-interference.In addition,metronidazole tablets were purchased from pharmacies as actual samples for sample detection.The results showed that the prepared sensor can be successfully used for the detection of metronidazole in samples,with a recovery rate of 96%-107%.2.Using tetracycline（TC）as the template molecule,o-phenylenediamine as the functional monomer,and nano-gold-copper alloy as the modified material,molecular imprinting was prepared on the surface of the carbon cloth（CC）electrode by electropolymerization under the three-electrode system Polymer membrane,successfully constructed a molecularly imprinted sensor for the detection of tetracycline.Cyclic voltammetry and scanning electron microscopy（SEM）were used to analyze the catalytic effect of the nano-gold-copper alloy.After optimizing the experimental conditions,through the electrochemical behavior of the sensor in different concentrations of tetracycline,the characteristics of the sensor are evaluated.According to the linear fitting result,the linear relationship is linear when the concentration is 1×10^-7～3×10^-5mol/L.The equation is IP=-0.5752 lgc+3.6307（IP:10-3A,c:mol/L）,linear correlation coefficient R²=0.9996 When the signal-to-noise ratio is 3,the detection limit is 2.5736×10^-11mol/L.And has good stability and anti-interference.In addition,purchasing milk from the supermarket for the detection of actual samples,the results show that the prepared sensor can be successfully used for the detection of tetracycline in the sample,and the recovery rate is between 93%and 106%.3.Using bisphenol A（BPA）as the template molecule,o-aminophenol as the functional monomer,and carbon nanotubes as the modified material,the flexible screen-printed electrode is prepared on the surface of the printed electrode by electropolymerization under the three-electrode system.A molecularly imprinted polymer membrane was used to successfully construct a molecularly imprinted sensor for the detection of BPA.Cyclic voltammetry and differential voltammetry were used to analyze the catalytic effect of the modified materials.After optimizing the experimental conditions,the characteristics of the sensor were evaluated through the electrochemical behavior of the sensor in different concentrations of BPA.According to the linear fitting results,a linear relationship is established in the concentration range of 1×10^-9～2×10^-8mol/L,and the detection limit is calculated to be 4.021×10^-11mol/L（S/N=3）,and the correlation coefficient R²=0.99102,and there is a good Stability and anti-interference.In addition,the modified electrode was used for the determination of BPA content in drinking water and plastic products.The results showed that the prepared sensor can be successfully used for the detection of BPA in samples.The recovery rates in the two samples were 93.8%and 94.2%,respectively.