SYSTEM FOR MEASURING CARBON DIOXIDE CONCENTRATION IN WATER AND METHOD THEREOF

摘要

An apparatus for measuring the concentration of carbon dioxide in water that can correct a reduction in measurement accuracy based on deterioration of a pH indicator is provided. A carbon dioxide concentration measurement apparatus 1 includes a deterioration determining section 31 that measures a change rate ”A 0 of an isosbestic point absorbance A 0 and determines that the pH indicator solution is deteriorated when the change rate ”A 0 is reduced by a predetermined reduction rate or more. After the deterioration determining section 31 determines deterioration of the pH indicator solution, a pH value computing section 27 computes the pH value of the pH indicator solution using a corrected pH computation expression for correcting a deterioration of the pH value of the pH indicator solution on the basis of the change rate ”A 0 of the isosbestic point absorbance A 0 .