1956 年 76 巻 6 号 p. 743-744
Determination of santonin in preparations by measuring the optical density of its 2, 4-dinitrophenylhydrazone was followed. It was found that by the use of a mixture (1:1) of ammonia water (Special Reagent Grade, ca. 28%) and acetone to bring the final concentration of ammonia to approximately 5.6 w/v% effected stabilization of the coloration for a comparatively long period of time (over 1 hour). By this modified method, several samples can be lined up for concurrent determination and would be convenient for application in plants. The determination error is within ±0.4% when using a sample corresponding to 40mg. of santonin.