Patent ID: 7641784
Filing Date: 2010-01-05
Classification: G01N

Abstract:
1. A method of measuring a concentration of a specific substance contained in a measurement sample by use of a chemical sensor comprising at least a working electrode and a reference electrode, wherein the method is a measurement method according to such a procedure that the chemical sensor is immersed into a buffer solution of a predetermined composition used as a storage liquid during standby, and a predetermined measurement bias is applied between the working electrode and the reference electrode to hold the chemical sensor in the buffer solution, and the chemical sensor is immersed into the measurement sample instead of the buffer solution, and the measurement bias applied between the working electrode and the reference electrode is used to measure the concentration of the specific substance contained in the measurement sample based on a change in an amount of a current produced by an electrochemical reaction during measurement; and the method comprising the following procedure for initial treatment, at the stage of making first use of the chemical sensor: as a first bias application after immersing the chemical sensor kept under a dry state into the buffer solution to bring the surfaces of the working electrode and reference electrode into contact with the buffer solution, a first initial treatment step of applying a first initial treatment bias having the same direction as that of the measurement bias and possessing an absolute value larger than that of the measurement bias between the working electrode and the reference electrode to hold the chemical sensor in the buffer solution for a predetermined first initial treatment time; a second initial treatment step of changing the bias to be applied between the working electrode and the reference electrode to a second initial treatment bias which is the same as the measurement bias, after ending the first initial treatment step, while the chemical sensor is immersed in the buffer solution, and holding the chemical sensor in a standby state; and after the completion of the second initial treatment step, the chemical sensor is placed for the first time at the use for measurement of the measurement sample, wherein any bias applied between the working electrode and the reference electrode during said procedure for initial treatment has the same direction as that of the measurement bias.