The total nitrogen measurement method by UV method

摘要

PURPOSE:To remove and correct the influence component of turbidity assuredly and highly accurately by measuring absorbance at a different second measuring wavelength on the long wavelength side which is relatively separated from a basic measuring wavelength in addition to the absorbance at the basic measuring wavelength. CONSTITUTION:When a specified time has elapsed from the end of the measurement of a zero signal, a specimen which has undergone heating decomposition and standing process is introduced into a measuring cell 7. During this period, the state wherein a first interference filter 4A is provided between a condenser lens 2 and a beam splitter 3 and the state wherein a second interference filter B is provided therebetween are switched. The measured signals are read in the respective states. In an operation circuit 10, the apparent absorbance whose zero point is corrected at a basic measuring wavelength and the absorbance (turbidity value) whose zero point is corrected at the second measuring wavelength are obtained. Then, the influence component due to the turbidity of the specimen is removed and corrected, and the true absorbance through nitric acid ions in the specimen at the basic measuring wavelength is obtained. The absorbance is transformed into the concentration of total nitrogen in the specimen by the measurement of the inside.