微量亜硝酸の抽出比色定量

概要

論文の詳細を見る
One of the most widely used colorimetric methods for the determination of nitrite is the one involving formation of a red azo-dye. It has been found by the authors that the azo-dye, having positive charge, is quantitatively extracted into carbon tetrachloride by coupling with the negatively charged ion of alkylbenzenesulfonate. Thus, the sensitivity becomes several times higher in this method than in the ordinary method. To a 50 ml sample solution are added 1 ml of 1% sulfanilamide in 1.2M hydrochloric acid solution and 1 ml of 0.1% N-1-naphthylethylenediamine dihydrochloride aqueous solution. After 10 min, 5 ml of carbon tetrachloride and 1 ml of 0.03% dodecylbenzenesulfonate aqueous solution are added. The azo-dye is extracted by shaking for 3 min, and the absorbance is measured at 525 mμ. This method is applied to the determination of trace amount of nitrite in fresh water.
社団法人日本分析化学会の論文