CONCENTRATION MEASUREMENT METHOD AND DEVICE

To enable an accurate management of concentration to be carried out, even in a region where the component concentration of a solution is high.SOLUTION: A measuring instrument 101 measures the light transmission characteristic of the process liquid to be measured. The measuring instrument 101 is composed, for example, of a spectrophotometer, and measures a spectral characteristic as the light transmission characteristic. A processing unit 102 finds a difference in concentration from a reference liquid of the process liquid by comparison of the result having been measured by the measuring instrument 101 with the reference value of light transmission characteristic measurement result of the reference liquid, of which the concentration of the process liquid is known. The concentration of the reference liquid can be a desired concentration in actual use of the process liquid.SELECTED DRAWING: Figure 1 【課題】溶液の成分濃度が高い領域でも、正確な濃度管理が容易に実施できるようにする。【解決手段】測定器１０１は、測定対象の処理液の光透過特性を測定する。測定器１０１は、例えば、分光光度測定器から構成され、光透過特性として分光特性を測定する。処理部１０２は、測定器１０１が測定した結果と、処理液の濃度が既知の基準液の光透過特性の測定結果の基準値との比較により、処理液の基準液からの濃度の差を求める。基準液の濃度は、処理液の実使用における目的の濃度とすることができる。【選択図】 図１