METHOD FOR MEASURING TOTAL NITROGEN BY ELIMINATING INFLUENCE OF BROMIDE

摘要

PURPOSE:To obtain exactness by measuring absorbancy at arbitrary two wavelengths with a liquid prepd. by diluting a sample and a sample liquid prepd. without diluting the same, then by making calculation by using the absorbancy obtd. in such a manner. CONSTITUTION:The sample water is diluted twice by pure water to decrease the concn. of the sea water to =1.5-2.0% in the case of, for example, the sea water sample. This sample water is then put into a high-pressure steam sterilizer, etc., where an oxidizing agent and an alkaline agent, etc., at need are added to the sample water. The vessel is hermetically closed and is heated. The decomposed liquid is taken out and an acid is added at need to the liquid to adjust the pH to 2-3. The measurement of the absorbancy of this soln. is executed by selecting the measuring wavelengths at two wavelengths, for example, 220nm and 210nm or 220nm and 215nm and calculating the content of nitrogen by calculation from the absorbancies at the two wavelengths. The correct content of the nitrogen is thereby determined.