Construction And Performance Study Of Glycerol Electrochemical Biosensor

Glycerol is the main by-product in the initial fermentation of wine,and it is one of the important bases for identifying the quality of wine.Under normal circumstances,the concentration of glycerol produced by wine fermentation is usually 1-10 g·L^-1,and the ratio of glycerol to ethanol is about 7%-10%.In the process of wine production,some unscrupulous traders add glycerol to blended wine to enhance the complexity of wine taste.This kind of behavior is strictly prohibited in China and other countries.Therefore,it is of great practical significance to realize the rapid and effective detection of glycerol content in wine.In this paper,based on materials such as nano zinc oxide,carboxylated nano zinc oxide,biological enzymes and nickel nanoparticles,the glycerol electrochemical enzyme biosensors and enzyme-free sensor were constructed to effectively and quickly detect the glycerol content in wine.Researches had been carried out on the preparation of carrier materials and catalytic materials,the immobilization of biological enzymes and metal catalyst,etc.The main contents were as follows:Nano zinc oxide material was synthesized by direct precipitation method,and the preparednano zinc oxide material,glycerol kinase as well as glycerol triphosphate oxidase were embedded on the electrode surface using chitosan to prepare an enzyme-modified electrode for glycerol detection.Electrochemical methods such as cyclic voltammetry,AC impedance spectroscopy and chronoamperometry were used to study the electrochemical performance of the sensor.The results showed that the reaction process on the sensor was controlled by diffusion instead of the surface adsorption in the system.The sensor had a good linear relationship with the concentration of glycerol in the range of 0.025m M-50m M;the linear equation was I??A?=0.99C?m M?+32.408;the correlation coefficient was R²=0.9989;thestability,and anti-interference,and could effectively detect the glycerol content in actual wine samples.The nano zinc oxide material was functionally modified by the method of radical polymerization to prepare a carboxylated nano zinc oxide material.Chitosan was electrodeposited on the electrode surface,and then the carboxylated nano zinc oxide was covalently combined with chitosan with the action of electricity.Finally glycerol kinase and glycerol triphosphate oxidase were dropped on the electrode surface to complete their covalent bonding with the carboxylated nano zinc oxide to produce an enzyme-modified electrode for detecting glycerol.The electrochemical performance of the sensor was studied by electrochemical methods such as cyclic voltammetry,AC impedance spectroscopy,and chronoamperometry.The results showed that the reaction process on the sensor was controlled by diffusion instead of the surface adsorption.The sensor had a good linear correlation with the concentration of glycerol in the range of 0.025 m M-60 m M;the linear equation was I??A?=1.078C?m M?+39.864;the correlation coefficient was R²=0.9982;the detection limitcould effectively detect the glycerol content in the actual wine samples.It could be seen from the comparison that the overall performance of the glycerol enzyme sensor prepared by this method was superior to the glycerol enzyme sensor prepared by the method of embedding drip coating using in the previous system.Nafion was used to fix the prepared nano zinc oxide on the surface of electrode firstly,and then the nickel nanoparticles was synthesized on the surface of nano zinc oxide by electrodeposition.Finally the nafion was dropped on the surface of nickel nanoparticles to prepared an enzyme-free modified electrode.Electrochemical methods such as cyclic voltammetry,AC impedance spectroscopy and chronoamperometry were used to study the electrochemical performance of the sensor.The results showed that the reaction process on the sensor was controlled by diffusion instead of the surface adsorption.The sensor had a good linear relationship with the concentration of glycerol in the range of 0.2m M-60m M;the linear equation was I??A?=2.969C?m M?+151.281;the correlation coefficient was R²=0.9955;theless affected by temperature and had good reproducibility,stability as well as anti-interference ability.It could effectively detect the content of glycerol in real wine samples.The electrochemical enzyme biosensors as well as the enzyme-free sensor prepared in the study had good performance and could be applied to the rapid detection of glycerol content in wine,which had certain reference and practical value for the research of glycerol sensor.