抄録
Phenacetin (p-acetophenetidine) was determined colorimetrically by effecting hydrolysis by boiling with hydrobrornic acid to form p-aminophenol, adding 1% o-cresol solution to its solution in a concentration of 4-10γ/cc., and in alkalinity (pH 11.0-11.8) rendered by 0.1N sodium hydroxide and submitting the blue indophenol thereby formed to colorimetry at 605mμ. This method of determination is not interfered by the presence of acetanilide, acetylsalicylic acid, caffeine, aminopyrine, or diphenhydramine hydrochloride. The amount of phenacetin in various preparations was determined in 98-102% of the theoretical amount by this method. When the preparation contains phenyl salicylate, aqueous 1% phenol solution is added and similarly submitted to colorimetry at 620mμ. The coloration will slacken if the amount of light is small in this reaction, so that the reaction should be carried out in a well-lighted place.
