Research On Modified Three-electrode With Nano Gold/graphene Composites For Alcohol Biosensor

This thesis mainly studies the three-electrode ethanol biosensor as well as how to use nano-gold/graphene composites to improve the sensor performance. Following are the main contents of this thesis.1. The study of preparing a three-electrode through screen printing technology. A three-electrode uses a carbon electrode as the working electrode and counter electrode, with Ag/Ag Cl as the reference electrode. To achieve the best three-electrode, this thesis designs the shape and structure of three-electrodes. It also applies the study of cyclic voltammetry research on the characteristic of the three-electrode system. According to the experiment results, when the diversity potential between oxidation peak and reduction peaks is less than 100 mv, the peak shape was obvious and the reversibility was good. Therefore, carbon electrodes can realizes the exchange electronics rapidly with potassium ferricyanide. These properties indicate that carbon electrode can be used for research in this system.2. The study of preparation and property research of the disposable ethanol biosensor. By curing analysis liquid to the three-electrode, ethanol biosensor can be prepared. By testing the density of alcohol, the relationship between the ethanol density and current is obtained. In this thesis, the optimum working requirements of the alcohol sensor is probed, including the quantity of reactants, PH value of the solution, the test temperature and working voltage.3. The study of preparing nano-gold/graphene composites. PVP was used as a protective solution, while ascorbic acid(vitamin C) was used as a reducing agent to produce nano gold/graphene composites. Through SEM observation and analysis, the reduced gold granules are distributed on the surface of the graphene and there was no significant agglomeration. This illustrated that the size of the gold particles is relatively small and particles were uniformly dispersed. The diameter of Nano-material particles characterized by TEM is about 20~50nm.4. The study of modifying working electrodes and ethanol sensors through nano gold/graphene. Electrochemical is analyzed through cyclic voltammetry, and the sensor was used to detect the density of ethanol. The sensor has a good repeatability and stability, whose reaction time is 20 seconds. Besides, the linear relationship between ethanol density and current is good.