Patent ID: 10056248

Abstract:
To allow online monitoring of the overall concentration of oxidizing substances in electrolyzed sulfuric acid, for example, in a cleaning system, absorbance data having undergone baseline correction in relation to the overall concentration of oxidizing substances by using a standard sample liquid in the form of an electrolyzed sulfuric acid preparation liquid having the same sulfuric acid concentration as the sulfuric acid concentration of the electrolyzed sulfuric acid is prepared, and absorbance is measured over wavelengths ranging from 190 to 290 nm by using a sample liquid in the form of electrolyzed sulfuric acid having a sulfuric acid concentration ranging from 60 to 97% by mass and a liquid temperature ranging from 20 to 70° C. to measure the overall concentration of oxidizing substances in the electrolyzed sulfuric acid on the basis of the data. The overall concentration of oxidizing substances in the electrolyzed sulfuric acid can thus be immediately measured.