Patent ID: 6340428
Filing Date: 2002-01-22
Classification: C12Q

Abstract:
A method for determining the concentration of a substrate in a sample solution using a biosensor comprising an electrically insulating base plate, an electrode system having a working electrode, a counter electrode and a third electrode to be used as an interfering substance detecting electrode, each being formed on said base plate, and a reaction layer which contains at least an oxidoreductase and an electron mediator and is formed on the electrode system omitting the third electrode, wherein said electron mediator is reduced by the produced electrons upon reaction between the substrate contained in the sample solution and the oxidoreductase to measure a reduced amount of said electron mediator electrochemically,said method being characterized by comprising: (a) a step of applying a voltage between the counter electrode and the third electrode; (b) a step of supplying the sample solution to the reaction layer; (c) a step of detecting an electrical change between the counter electrode and the third electrode due to supply of the sample solution to the reaction layer; (d) a step of measuring a current flowing between the counter electrode and the third electrode after said detecting step (c); (e) a step of releasing voltage application between the counter electrode and the third electrode after said measuring step (d); (f) a step of applying a voltage between the working electrode and the counter electrode; and (g) a step of subsequently measuring a current flowing between the counter electrode and the working electrode.