The study of PVP/Pd/IrO2 modified sensor for amperometric determination ofsulfur dioxide

A novel electrochemical sensor for the detection of sulfur dioxide in both gas and solution is described. The chemically modified electrode was constr ucted by polymerizing (4-VP), palladium and iridium oxide (PVP/Pd/IrO2) ont o a platinum microelectrode which exhibits excellent catalytic activity tow ard sulfite with an oxidation potential of + 0.50 V. The SO2 gas sensor is based on the PVP/Pd/IrO2 modified electrode as working electrode, Ag/AgCl e lectrode as reference electrode, Pt electrode as counter electrode and a po rous film, which is in direct contact with the gas-containing atmosphere. T he effect of different internal electrolyte solutions of hydrochloric acid, sulfuric acid, phosphates buffer solution, mixed solution of dimethyl sulf oxide and sulfuric acid to the determination of SO2 was also studied. The s ensor was found to have a high current sensitivity, a short response time a nd a good reproducibility for the detection of SO,. It has good potential t o be used in the field of environmental monitoring and controlling. (C) 200 1 Elsevier Science B.V. All rights reserved.