抄録
The degree of coloration, specificity and stability of pentose with various compositions in different heating period of the various polyphenol reagents in the mixed solvent of hydrochloric acid and acetic acid have been investigated. The activity of resorcinol and orcinol in diphenol group has been observed as a coloration reagent and the isomers of triphenol were found to be effective for coloration reagent. Because of the instability of hydroxyhydroquinone, its triacetate was used for the test. All of the compounds examined possess two hydroxyl groups commonly at meta position, which were considered to be related closely to the coloration reaction. An optimal condition of polyphenols for the colorations is: resorcinol reagent showed a low degree of coloration; phloroglucinol and hydroxyhydroquinone reagent showed unstable coloration; orcinol reagent was superior to the specificity, though the degree of coloration was low; and pyrogallol reagent had a high degree of coloration, being inferior to the specificy. It was concluded that the phenolic compounds mentioned above were available to the quantitative colorimetry of pentose.
