Electrochemical Sensor Based On Carbon-based Composite Material For Rapid Detection Of Nitrite In Food

Food safety has always been a key topic of concern to the society.In the face of the increasing demand for food safety testing,simple operation,fast,efficient,low-cost,and high-precision are the key to solving the rapid detection of nitrite content in food safety.Based on the principle of electrochemical sensors,with the goal of serving food safety,electrochemical detection research is carried out for NO₂^-in food.In this paper,carbon-based nanocomposite materials are used to prepare two nitrite electrochemical sensors with high sensitivity,fast detection speed and low price through a simple and environmentally friendly manufacturing method,which can promote the rapid detection of nitrite content in daily food.（1）The AuNPs and MWCNTs/RGO were modified on the glassy carbon electrode by the drop coating method and the negative potential reduction method to prepare a gold nanometer multi-walled carbon nanotube reduction graphene oxide composite material modified glass for detecting NO₂^-Electrochemical sensor of carbon electrode（AuNPs/MWCNTs/RGO/GCE）.Electrochemical impedance spectroscopy（EIS）and cyclic voltammetry（CV）were used to measure glassy carbon electrode（GCE）,reduced graphene oxide/multi-walled carbon nanotubes/glassy carbon electrode（MWCNTs/RGO/GCE）,nano-gold/The morphology and electrochemical properties of glassy carbon electrodes（AuNPs/GCE）,gold nanoparticles/multi-walled carbon nanotubes/reduced graphene oxide/glassy carbon electrodes（AuNPs/MWCNTs/RGO/GCE）were characterized.Under the best experimental conditions,AuNPs/MWCNTs/RGO/GCE have good electroreduction catalytic activity for nitrite（pH=4）.CV,DPV,and it methods were used to quantitatively detect nitrite.The linear detection ranges were 10-600μmol/L,10-800μmol/L,2-4400μmol/L,and the corresponding correlation coefficients were 0.997,0.997,0.996.,The detection limit of i-t method is 0.219μmol/L.The anti-interference test of common ions in food by the i-t method proves that the nitrite electrochemical sensor has good selectivity.（2）A reduced graphene oxide paper electrode（RGOPE）was prepared by chemical reduction and vacuum filtration,and a reduced graphene oxide paper electrode modified with gold nanoparticles（AuNPs）was prepared by electrodeposition.To construct a nitrite electrochemical sensor.Scanning electron microscopy（SEM）,electrochemical impedance spectroscopy（EIS）and cyclic voltammetry（CV）were used to characterize the morphology and catalytic performance of RGOPE and AuNPs/RGOPE,respectively.Under the best experimental conditions,AuNPs/RGOPE has good electroreduction catalytic activity for nitrite（pH=5）.The time-current method（i-t）was used to quantitatively detect nitrite.The linear detection range was 0.2-2400μmol/L,the correlation coefficient was 0.995,and the detection limit was 0.048μmol/L.The anti-interference test of common ions in food by the i-t method proves that the nitrite electrochemical sensor has good selectivity.The detection of nitrite in mustard,ham and tap water samples showed that the average recovery rate was between 90.94%and 102.26%,which proved that the sensor has good applicability.In summary,the two nitrite electrochemical sensors prepared in this article not only have the advantages of simple preparation method,low price,wide detection range,low detection limit,fast detection speed,good selectivity,and high reproducibility,but also have good advantages.Applicability.