Construction Of Electrochemical Sensor Modified With Nickel Foamed Supported Nanomaterials And Its Study On Nitrite Detection

Nitrite is widely used in meat products as a color protector and preservative.However,excessive intake of nitrite will cause serious harm to human health.Therefore,it is of great significance to establish an accurate and rapid detection method for nitrite in meat products.The electrochemical method for detecting nitrite has the advantages of high sensitivity and can meet the needs of rapid on-site detection.Nickel foam is a good material for electrode substrate because of its porous structure,large specific surface area and good electrical conductivity.Transition metal oxide nanomaterials have the advantages of a wide range of sources and good catalytic performance,which can be used as electrode modification materials to improve the stability and sensitivity of the sensor.Therefore,in this paper,two nanocomposites Co3O4/nickel foam and CoFe2O4/nickel foam were synthesized as electrode materials to prepare nitrite electrochemical sensors with the nickel foam as the carrier,which achieved relatively ideal results.The specific content is as follows:(1)Nickel foam supported Co3O4 composites were prepared by hydrothermal method and high temperature calcination using nickel foam as a carrier for the construction of a high-sensitivity nitrite electrochemical sensor.The morphology and structure of the prepared nanomaterials were characterized by scanning electron microscopy(SEM),transmission electron microscopy(TEM)and X-ray diffraction(XRD).The electrochemical behavior and electrocatalytic mechanism of nitrite rapid detection with modified electrode were studied by cyclic voltammetry(CV),chronoamperometric titration(i-t)and and other electrochemical methods.The results show that the linear range of Co3O4/nickel foam electrochemical sensor is 5-2000μmol/L,the detection limit is 3.14 μmol/L and the recovery rate is 97.1%～102.7%.(2)By simplifying the preparation process,bimetallic cobalt oxide was directly synthesized on nickel foam by hydrothermal method to obtain CoFe2O4/nickel foam nanocomposite material with excellent performance,which was used to construct nitrite electrochemical sensor.The morphology and structure of the prepared nanomaterials were characterized by scanning electron microscopy(SEM)and other methods.The electrochemical behavior and electrocatalytic mechanism of nitrite rapid detection with modified electrode were studied by cyclic voltammetry(CV),chronoamperometric titration(i-t)and and other electrochemical methods.The linear range of the electrochemical sensor is 3～1500 μmol/L,the detection limit is 2.31 μmol/L and the recovery rate is 93.6%～103.3%.The two electrochemical sensors designed in this paper have the advantages of high sensitivity,easy operation,good stability and short detection time,which are suitable for the rapid detection of nitrite in meat products.