アンスロンによるペントースの呈色反応 (第1報)

フルフラール-アンスロン反応

抄録

The existing coloration reaction for sugars by the anthrone reagent differs in reactivity according to the kind of sugars but is common to various sugars such as hexose, methylpentose, and pentose. In carrying out the reaction, it is necessary to cause heat generation by mixing of the test solution and the reagent or heating. Coloration of pentose and furfural is somewhat more labile than that of other sugars and the color tends to fade by excessive heating.
It was found that there is a furfural-anthrone coloration reaction different from the known sugar-anthrone reaction. In this case, 1cc. of furfural (1-50γ/cc.) and 10cc. of the coloration reagent (0.1% of anthrone in a mixture of 6 volumes of conc. sulfuric acid and 4 volumes of 85% phosphoric acid) are mixed under cooling to avoid generation of heat, allowed to stand in flowing water for 40 minutes, and a deep blue color with absorption maximum at 600mμ is produced. The relationship between furfural concentration and absorbance meets the Beer's law and this coloration can be utilized for determination of furfural. If pentose is heated preliminarily with sulfuric or phosphoric acid, cooled, and the foregoing coloration reaction is carried out, coloration highly characteristic to pentoses is obtained. This coloration also follows the Beer's law.