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Fast Yellow

Fast Yellow

Class: Azo
Ionisation: Acid

Chemical structure of Fast Yellow

Common Name: Fast yellow
Suggested Name: Fast yellow
Other Names:

Fast yellow G, Fast yellow extra, Acetyl yellow

C.I. Number: 13015
C.I. Name: Acid yellow 9
Color: Yellow
Solubility Aqueous: 18.40%
Solubility Ethanol: 18.40%
Absorption Maximum: 490 (Conn), 381 (Gurr)
Empirical Formula: C13H9N3O6S2Na2
Formula Weight: 401.342


This dye is not commonly used, but it has been specified in Wallart & Honette's trichrome stain, where it stains collagen yellow, in contrast to red cytoplasm.


  1. R. D. Lillie.
    Conn’s Biological Stains
    Williams & Wilkins, Baltimore, MD., U.S.A.
  2. Edward Gurr, 1971
    Synthetic dyes in biology, medicine and chemistry
    Academic Press, London, England.