Research Of Polypyrrole Sensors

As one of the famous conducting macromolecules, Polypyrrole is applied extensively in sensors. In this paper, the conditions of the preparation of Polypyrrole/Glucose Oxidase electrode and the characteristic of the Polypyrrole gas sensor was discussed.When some gas molecule is adsorbed in the Polypyrrole membrane, the conductivity of the membrane changes. The concentration of the gas could be detected by measuring the change of the conductivity . In the experiments, the Polypyrrole gas sensor was prepared on screen-printed electrodes by CVD(Chemical Vapor Deposition) . The effect of the electrochemistry undoping and doping on the characteristic of the gas sensor was studied. The sensor was sensitive to NH3, whose concentration was as low as 10ppm. When the Polypyrrole was undopped by electrochemical method, the sensitivity of the sensor reduced. When the Polypyrrole was dopped by electrochemical method again, the sensitivity of the sensor enhanced. The dopping of ClO4- had a great effect on the sensitivity of the sensor.The Glucose Oxidase could be immobilized in the Polypyrrole membrane when the pyrrole is polymerizing on the electrode. In the experiments , the conditions of the preparation of the Polypyrrole/Glucose Oxidase electrode were studied. The concentration of pyrrole, the concentration of the enzyme, the pH of solution, and the volume of charge had a great effect on the preparation of the electrode.When the concentration of enzyme was 2mg/ml,the concentration of pyrrole was 0.05M, the concentration of LiClO4 was 0.05M, the pH of solution was 5.0, the polymerization potential was 0.8V(vs.SCE)and the volume of polymerization charge was 2.5mC, the response of Polypyrrole/Glucose Oxidase electrode was high.