Abstract: An enzyme electrode for a chemical sensor includes an electrode including a pair of working electrodes, a reference electrode and a counter-electrode. A first film is formed on one of the working electrodes, which includes a polyvinyl alcohol and a surface-active agent. A second film is formed on the other working electrode including polyvinyl alcohol, surface-active agent and enzyme. An overcoat film of high polymer electrolyer including a pH buffer is formed on the first and second films. The polymerization degree of the polyvinyl alcohol is from 300 to 3000 and the high polymer electrolyer may be alginic acid, polystyrene sulfonic acid or polyacrylic acid, and the pH buffer is a positive ion having a valence of 1.

Abstract: A voltage applying method for a hydrogen type enzyme electrode in a chemical sensor and using a pair of working electrodes, a reference electrode and a counter electrode includes detecting a contact of a test specimen with the enzyme electrode; keeping a potential applied to the working electrodes at a first potential of substantially zero for a first preset time; applying a second potential that is higher than a hydrogen peroxide detect potential to the working electrodes for a second preset time; dropping the second potential to a third potential below zero potential; and sweeping from the first potential to a fourth potential higher than said hydrogen peroxide detect potential at a fixed rate. Other variations of the method are disclosed.