METHOD AND DEVICE FOR MEASURING NITRIC ACID CONCENTRATION BY CONTINUOUS FLOW ANALYSIS METHOD

摘要

PROBLEM TO BE SOLVED: To rapidly and accurately measure the concentration of not only a high-concentration nitric acid solution but also a low-concentration nitric acid solution by using measurement light including a plurality of wavelengths with an absorption region for a nitric acid ion and selecting the wavelength of measurement light according to the nitric acid concentration of a sample liquid and measuring absorbance. ;SOLUTION: A target sample liquid is selected by a switching valve 12 and the sample loop of an injection valve 11 is filled with the sample liquid by a suction pump 14. Then, the injection valve 11 is opened, the sample liquid is fed to a pipeline 40 and is fed to a measurement part 30 via a dilution part 20 by a carrier liquid that flows in the pipeline 40, and the absorbance is measured. When the nitric acid concentration level of the sample liquid is known in advance, the wavelength of the measurement light is selected according to the nitric acid concentration level and an absorbance is measured by the measurement light with a proper wavelength. Concretely speaking, light with a wavelength of 280nm-330mm has an absorption liquid for nitric acid ion so that it is used for measurement. The wavelength of the measurement light is selected after measuring the nitric acid concentration level of the sample liquid in advance by preliminary measurement when the level of the nitric acid concentration is known.;COPYRIGHT: (C)1998,JPO