| 摘要 |
[Problem] To measure the concentration of a dissolved substance, and also detect the presence or absence of the addition of a reagent. [Solution] In the measurement of the concentration of a given dissolved substance in water of interest (W0) using sample water (W1) which is prepared by adding each of two types of reagents to the water of interest (W0) and develops a predetermined color in a predetermined pH range (H0), an acid/base indicator reagent (S) is selected, wherein the acid/base indicator reagent (S) can develop different colors, which are different from the predetermined color, in a first pH range (H1) including the predetermined pH range and in a second pH range (H2) excluding the first pH range from each other. Subsequently, each of the two types of the reagents (A0, B0) is added to the water of interest to prepare added water (T), and one of the reagents ((A0) of which the added water (T) has a pH value falling within the second pH range is mixed with the acid/base indicator reagent to prepare a reagent. Subsequently, with respect to the sample water (W1) to which the prepared reagent has been added, absorbance values (Ra··) to three regions of component light, which are transmitted light (J), are calculated. Subsequently, the concentration of the given dissolved substance is calculated and the presence or absence of the addition of the two types of the reagents is also determined on the basis of the absorbance values. |
