| 摘要 |
PURPOSE:To perform fractional determination of very small amount of total nitrogen, nitrous acid state nitrogen, and nitric acid state nitrogen accurately in a short time by combining a distilling part and a measuring part which are scarcely affected by water. CONSTITUTION:Sample water is injected in an introducing port 4 in a mesuring part 1, and introduced to reacting part 25 together with H2 gas which is introduced from an introducing pipe 26. Nitrogen compound is reduced to NH3. NH3 is introduced to an electrolytic bath 19 via an acidic gas removing part 20, and pipes 20 and 18, and absorbed by electrolyte. Coulometric titration is performed, and the titrated result is displayed on a coulometric titration control device 7, and total nitrogen is measured. Then the sample water is injected to a distilling tank 12 from an introducing port 11 in the distilling part 2, and nitrous acid state nitrogen is transformed into NO or NO2. It is introduced into the reacting part 25 via a returning condenser 6 and pipe 5, together with carrier gas introduced from an introducing port 10. Nitrous acid state nitrogen is measured by the similar means as total nitrogen. The sample water is reduced beforehand, nitric acid state nitrogen is reduced to nitrous acid ion, and nitric acid state nitrogen is measured by the similar means as nitrous acid state nitrogen. |
