水溶液およびアルコール溶液におけるビタミンK₅のポーラログラフ的挙動とビタミンK₅の定量への応用

抄録

The electrode reaction of vitamin K₅ (4-amino-2-methyl-1-naphthol hydrochloride) on a mercury electrode was studied by polarography in aqueous and alcoholic solutions. Vitamin K₅ shows two well-defined anodic waves on a direct current (DC) polarogram obtained from both aqueous and acidic ethanol solutions. One of them is due to the oxidation of 4-amino-2-methyl-1-naphthol (I) and its limiting current was found to be proportional to the vitamin K₅ concentration, and the other corresponds to the formation of mercurous chloride on the electrode surface. Electro-oxidation of I also gives rise to a distinct peak on an alternating current (AC) polarogram obtained from aqueous solution, whose height is proportional to the amount of vitamin K₅ in a very low concentration range. Such experimental results have been confirmed to be advantageously applicable to the microdetermination of vitamin K₅. The AC polarographic method can be applied to determine a minute quantity of vitamin K₅ as low as 0.1 ppm range. The simultaneous determination of vitamin K₅ and other vitamin K's can be made by the measurement of DC polarogram in acidic ethanol solution with satisfactory results.