Patent ID: 8961777
Filing Date: 2015-02-24
Classification: G01N

Abstract:
1. A method for accurately quantifying a chemical substance contained in a sample solution at a significantly low concentration of not more than 1×10 −8 M, the method comprising steps of: (a) preparing a measurement system including a counter electrode, a first reference electrode, a first working electrode, a second working electrode and a second reference electrode; (b) bringing the counter electrode, the first reference electrode, the first working electrode, the second working electrode and the second reference electrode into contact with the sample solution; wherein the sample solution contains the chemical substance and an oxidation-reduction substance or contains the chemical substance modified with an oxidation-reduction substance; (c) applying voltages of V On the first working electrode: (where, n represents an integer, and m represents a positive integer) On the second working electrode: (where, n represents an integer, and m represents a positive integer) (d) stopping the application of the voltage to the second working electrode, when the first predetermined period t (e) leaving the sample solution as it stands for a second predetermined period t (f) measuring a voltage difference ΔE between the second working electrode and the second reference electrode after the step (e); and (g) calculating a concentration of the chemical substance on the basis of the following formula (III) C C