| 摘要 |
<P>PROBLEM TO BE SOLVED: To quantitate total nitrogen of inspection water containing halide ions up to a high concentration region thereof with simple and safe operation, by using diazotization reaction with nitrite ions. <P>SOLUTION: A method for quantitating total nitrogen of inspection water comprises: a step 1 of adding alkali metal salts of peroxodisulfate to inspection water containing halide ions and heating the inspection water under alkaline conditions; a step 2 of adding at least one kind of phosphorous acid and a salt thereof and hypophosphorous acid and a salt thereof to the inspection water that has passed through the step 1 and heating the inspection water under acidic conditions; a step 3 of adding vanadium chloride (III) and a diazotization reagent capable of generating diazonium salts due to reaction with nitrite ions to the inspection water that has passed through the step 2 and heating the inspection water under acidic conditions; and a step 4 of measuring nitrate ion concentration by measuring absorbance of coloring with the diazotization reagent, for the inspection water that has passed through the step 3. An aromatic primary amine compound having a ketone group or a nitro group in an ortho position or in a para position is used as the diazotization reagent. <P>COPYRIGHT: (C)2013,JPO&INPIT |
