Method for measuring by means of chemical sensor, and chemical sensor type measuring apparatus
First Claim
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, at the stage of making first use of the chemical sensor, 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 a 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.
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Abstract
There is disclosed means for quickly solving instability of sensor sensitivity performances found in an initial stage and stabilizing the sensor sensitivity performances, when immersing a chemical sensor kept under a dry state in a buffer solution used as a storage liquid and applying a measurement bias between a working electrode and a reference electrode to make first use of the chemical sensor for measurement in which the chemical sensor is used. To make the first use of the chemical sensor, after immersing the chemical sensor kept under a dry state in the buffer solution used as the storage liquid, 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 is applied between the working electrode and the reference electrode for a first initial treatment time. Subsequently, the bias is changed to a second initial treatment bias which is the same as the measurement bias, and the second initial treatment bias is applied for a second initial treatment time. When such a two-step initial treatment operation is carried out, the stabilized sensor sensitivity performance is achieved.
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Citations
13 Claims
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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, at the stage of making first use of the chemical sensor, 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 a 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. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 12)
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11. A method of measuring a concentration of a specific substance contained in a measurement sample by use of a chemical sensor having 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, at every stage post to continued use of the chemical sensor for a predetermined period, in a condition in which the chemical sensor in a standby state is immersed in the buffer solution, and the surfaces of the working electrode and reference electrode are allowed to contact the buffer solution;
a first refresh treatment step of applying a first refresh 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, and holding the chemical sensor in the buffer solution for a predetermined first refresh treatment time;
a refresh standby treatment step of changing the bias applied between the working electrode and the reference electrode to a second refresh treatment bias which is the same as the measurement bias, after ending the first refresh treatment step, while the chemical sensor is immersed in the buffer solution, and holding the chemical sensor in a standby state for a second refresh treatment time; and
after completion of the refresh standby treatment step, the chemical sensor is placed again at the use for the measurement of the measurement sample. - View Dependent Claims (13)
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Specification