Indophenol Explained

Indophenol is an organic compound with the formula OC₆H₄NC₆H₄OH. It is deep blue dye that is the product of the Berthelot's reaction, a common test for ammonia.^[1] The indophenol group, with various substituents in place of OH and various ring substitutions, is found in many dyes used in hair coloring and textiles.^[2]

Indophenol is used in hair dyes, lubricants, redox materials, liquid crystal displays, fuel cells and chemical-mechanical polishing. It is an environmental pollutant and is toxic to fish.^[3]

Berthelot test

In the Berthelot test (1859), a sample suspected of having containing ammonia is treated with sodium hypochlorite and phenol. The formation of indophenol is used to determine ammonia and paracetamol by spectrophotometry.^[4] Other phenols can be used. Dichlorophenol-indophenol (DCPIP), a form of indophenol, is often used to determine the presence of vitamin C (ascorbic acid).^[5]

Related compounds

Indophenol blue is a different compound with systematic name N-(p-dimethylaminophenyl)-1,4-naphthoquinoneimine.^[6]

References

1. 10.1021/ac50011a034. Spectrophotometric and kinetics investigation of the Berthelot reaction for the determination of ammonia. Analytical Chemistry. 49. 3. 464–469. 1977. Patton. Charles J.. Crouch. S. R..
2. Encyclopedia: Horst Berneth. Ullmann's Encyclopedia of Industrial Chemistry. 2002. Wiley-VCH. Weinheim. 10.1002/14356007.a03_213.pub2. 978-3527306732. Azine Dyes.
3. Web site: Indophenol I5763. 2020-06-11. 500-85-6.
4. 12400662. 2002. Tsuboi. T.. Sensitivity improvement of ammonia determination based on flow-injection indophenol spectrophotometry with manganese(II) ion as a catalyst and analysis of exhaust gas of thermal power plant. Analytical Sciences . 18. 10. 1141–4. Hirano. Y.. Shibata. Y.. Motomizu. S..
5. 10.1002/jps.2600720208. Titrimetric Determination of Ascorbic Acid with 2,6-Dichlorophenol Indophenol in Commercial Liquid Diets. Journal of Pharmaceutical Sciences. 72. 2. 126–129. 1983. Hughes. David Emlyn.
6. 10.1126/science.139.3557.835 . Indophenol Blue as a Chromogenic Agent for Identification of Halogenated Aromatic Hydrocarbons . Science . 139 . 3557 . 835–836 . 1963 . Graham . S. O. . 1963Sci...139..835G .