ジアゾカップリング反応を用いたニトロプルシッドナトリウムの定量  [in Japanese] Determination of Sodium Nitroprusside by Diazo-Coupling Reaction  [in Japanese]

A method for the determination of sodium nitroprusside by diazo-coupling reaction was established. Sodium nitroprusside was quantitatively derived to nitrite in strong alkaline medium. The following procedure is recommended; To 0.5 ml of a sample solution, 1.O ml of O.2M sodium hydroxide was added, and this reaction mixture was stood for 15 min under the room light, Then, 1.O ml of 1% sulphanilamide reagent (1.2 M hydrochloric acid solution) was added to the reaction mixture. After mixing and standing for 2 min to 6 min, 1.O ml of 0.1% N-(1-naphthyl) ethylenediamine solution was added to the reaction mixture, and the absorbance of the reaction mixture was measured at 540 nm against the reagent blank. The calibration curve for sodium nitroprusside is rectilinear in the range of (1〜200) μM. Sodium nitroprusside present in the sample was calculated from the increase in nitrite measured in the alkaline treated sample compared to that obtained without alkaline treatment. The photo-stability of sodium nitroprusside was also investigated.