Abstract
Formerly, one of the authors found that the indophenol-butanol solution was very stable and applying this stability, he proposed an indophenol-butanol titrimetric method for determination of vitamin C. The drawback of the former indophenol method due to the instability of the indophenol aqueous solution, was thus obviated. Recently, the authors confirmed spectrophotometrically the stability of indophenol-butanol solutions, that is to say, even such a thin solution as that of 3mg% was stable for 8 weeks and moreover it was not discolored by acids. Applying the stability of the above solution to the colorimetric method, the authors established the indorphenol-butanol colorimetric method. Moreover the authors confirmed that, in this method, p-chloromercuribenzoate, which was proposed by Owen et al. as removing reagent for SH-compounds, completely removed not only such SH-compounds as reduced glutathione and cysteine but also H_2S, Na_2S_2O_3 and Na_2SO_3. By this method, the vitamin C in plant tissues and human blood could be determined very accurately, and values obtained by this method agreed well with the measured by the ascorbic acid oxidase method.
