Application Of Electrochemical Sensors Modified By Oxide Nanomaterials In The Determination Of Glucose And Hydrogen Peroxide

As the scale of urban modernization and industrialization continues to expand,foods with rich varieties and complete functions have flooded into the market,and people's material living standards have been rapidly improved.However,serious food safety incidents have forced producers and consumers to focus on food safety issues.Glucose and hydrogen peroxide are rich in small molecules in food.Their content will directly or indirectly affect the quality and shelf life of the food.If the content exceeds the normal standard,it will endanger human health.Traditional detection methods for small molecules such as glucose and hydrogen peroxide in food have disadvantages such as difficult operation,poor selectivity,and high detection cost,and cannot meet the needs of modern food detection for rapid,efficient,and continuous detection.Electrochemical sensor is a kind of detection instrument based on the transmission and analysis of electrical signals.The characteristics of convenience,speed and in-situ detection make it develop rapidly in the field of food composition detection.Through electrode modification,the excellent catalytic performance and electrochemical activity of metal and its oxide nanomaterials are combined with electrochemical sensors,which further expands the application range of electrochemical sensors and promotes the development of modern food detection technology(1)A simple two-step method was used to prepare Co3O4-NiO nanoneedles and construct a new type of electrochemical glucose sensor and hydrogen peroxide sensor.Using scanning electron microscopy,transmission electron microscopy,X-ray diffraction and other methods to characterize the morphology and structure of the prepared nanocomposite materials.Cyclic voltammetry and amperometric experiments show that,compared with NiO nanomaterials and Co3O4 nanomaterials,Co3O4-NiO nanocomposites exhibit higher oxidation effect on glucose and electrocatalytic effect on hydrogen perxide.Among them,the results of electrochemical experiments on glucose show that it has a good linear range at 1 ?M-3.4 mM and 3.4 mM-12.2 mM,the lowest detection limit is 0.81 ?M(S/N=3),and the sensitivity is 62 mA M-1 cm-2.The proposed sensor has high selectivity,good reproducibility and stability,and has obtained satisfactory results in actual sample detection(2)The Cu@Cu2O aerogel was prepared by a one-step reduction method,and its catalytic activity was studied.A simple,fast,and stable electrochemical glucose sensor and an enzyme-free electrochemical sensor for detecting hydrogen perxide were constructed respectively.X-ray diffractometer,ultraviolet spectrophotometer,transmission electron microscope,and scanning electron microscope were used to characterize the composition,and it was found that Cu@Cu2O aerogel shows an ultra-thin sponge-like structure,with a large surface-to-volume ratio,a large number of active sites and good solubility.The enzyme-free sensing system based on this material was studied and optimized by cyclic voltammetry and current-time curve.The results show that Cu@Cu2O aerogel has high-efficiency electrochemical activity for glucose oxidation,with good linearity in the range of 0.001-5.2 mM and 5.2-17.1 mM,the lowest detection limit is 0.6 ?M(S/N=3),and the sensitivity It is 195 mA M-1 cm-2.At a neutral pH,at a scan rate of 100 mV/s,it has a good linear range at 0.1-10 mM,the detection limit is 54 ?M(S/N=3),and the sensitivity is 12 mA M-1 cm-2.The Cu@Cu2O aerogel sensor platform also has an excellent electrochemical response to hydrogen peroxide,with good linear range between 2-210 ?mol/L and 210-860 ?mol/L,and the lowest detection limit is 1.16 ?mol/L(S/N=3).The proposed sensor has high selectivity,good reproducibility and stability,and has obtained satisfactory results in actual sample detection.