Classification | Colorimetric method |
---|---|
Analytes | Pentoses |
The aniline acetate test is a chemical test for the presence of certain carbohydrates, in which they are converted to furfural with hydrochloric acid, which reacts with aniline acetate to produce a bright pink color. Pentoses give a strong reaction, and hexoses give a much weaker reaction.[1]
Procedure and mechanism
[edit]A dry sample is dissolved in a small volume of hydrochloric acid and briefly heated. A piece of paper, previously impregnated with aniline acetate, is exposed to the vapor from the sample solution. A bright pink color on the paper is positive for the presence of pentoses.
![](https://upload.wikimedia.org/wikipedia/commons/thumb/1/1d/Furfural_skeletal.svg/220px-Furfural_skeletal.svg.png)
Hydrochloric acid dehydrates pentoses (sugars containing five carbon atoms) to produce furfural. The reaction of furfural and aniline produces a bright pink color. Hexoses, which are sugars which contain six carbons, are not dehydrated to furfural, and so they do not produce a pink color.
Interferences
[edit]3-Furanaldehyde responds to the usual tests for aldehydes, but unlike 2-furanaldehyde it gives no color test with aniline acetate.
References
[edit]- Notes
- ^ Seager, Spencer L.; Slabaugh, Michael R.; Hansen, Maren S. (2016-12-05). Safety Scale Laboratory Experiments. Cengage Learning. p. 358. ISBN 9781337517140.
- Bibliography
- A Method for the identification of pure organic compounds by a systematic analytical procedure based on physical properties and chemical reactions. v. 1, 1911. By Samuel Parsons Mulliken. Published by J. Wiley & Sons, Inc., 1904. Google Books link page 33.
- "Modifications of the aniline acetate-furfural method for the determination of pentose." The Analyst, 1956, 81, 598 - 601, doi:10.1039/AN9568100598 [1]