Soviet Medical Encyclopedia

Dimethylaminoazobenzene

Biochemistry, Pharmacology, Chemistry & Physics

Also known as: Butter Yellow, Topfer's reagent

Historical document, translated for reference. It reflects medical knowledge of the 1920s–30s and is not medical advice.

Summary

Dimethylaminoazobenzene is an organic base belonging to the azo dye group, used as a pH indicator ranging from 2.9 to 4.0. In medical practice, it is employed as Töpfer's reagent for determining free hydrochloric acid in gastric juice.

Encyclopedia entry (1928–1936)

DIMETHYLAMINOAZOBENZENE, C6H5N:NC6H4N(CH3)2, a base belonging to the group of azo dyes. It crystallizes from dilute alcohol. It is an indicator applicable within a pH range from 2.9 to 4.0; its color is red in an acidic medium and yellow in an alkaline medium. It is suitable for the titration of alkalis, even weak ones, and strong acids. It is used in the form of a 0.5% alcohol solution (Töpfer's reagent) in determining the acidity of gastric juice dependent solely on hydrochloric acid (1-2 drops of the indicator per 10.0 cm3).

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Cite this page

“Dimethylaminoazobenzene.” Soviet Medical Encyclopedia. English translation of Bolshaya Meditsinskaya Entsiklopediya, 1st ed. (Moscow, 1928–1936), ed. N. A. Semashko. https://sovietmedicalencyclopedia.pages.dev/article/dimethylaminoazobenzene/