塩化バナジウム（Ⅲ）還元-ナフチルエチレンジアミン吸光光度法による硝酸イオンの定量

摘要

塩化バナジウム（Ⅲ）により，硝酸イオンを亜硝酸イオンに還元して，これをナフナルエチレンジアミン吸光光度法で発色させる硝酸イオンの定量法を検討した。その結果，試料に発色試薬溶液のスルファニルアミド溶液（8mg・mL~(-1)）とN-1ナフチルエチレンジアミンニ塩酸溶液（0．4mg・mL~(-1)）とを加えてから還元剤である塩化バナジウム（Ⅲ）溶液（8mg・mL~(-1)）を加えて，60℃で10分間還元発色させればよいことが分かった。%The reduction of nitrate to nitrite with vanadium (II) chloride was studied. When vanadium (III) chloride solution was added to the sample solution after the addition of the color developing reagents, the reduction rate of nitrate to nitrite was ca.85%. The proposed procedure is as follows. A 2mL of sulfanilamide solution (8mg·L~(-1)) , 2mL of N-l naphthylethylenediamine solution (0.4.mg·L~(-1)) are added to the sample solution containing nitrate of 2.5 ～ 10μg as N, and then 2.5mL of vanadium (III) chloride solution (8mg·L~(-1)) is added to the solution. The sample solution is diluted to 50mL with distilled water and stood for 10min at 60℃ . After the cooling of the solution, the absorbance is measured at 540nm.