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Pontamine Sky Blue 5B

Pontamine Sky Blue 5B

Class: Azo
Ionisation: Acid

Chemical structure of Pontamine Sky Blue 5B

Common Name: Pontamine sky blue
Suggested Name: Pontamine sky blue 5B
Other Names:

Chicago blue 4B

C.I. Number:
C.I. Name:
Color: Blue
Solubility Aqueous: Readily
Solubility Ethanol: Readily
Absorption Maximum: 588 (Gurr)
Empirical Formula: C34H24N6O16S4Na4
Formula Weight: 993


A large molecular weight dye named pontamine sky blue was suggested as a substitute for methyl blue in Lendrum’s MSB technique for fibrin. It is likely this dye, but positive identification is not possible as a CI number was not given. It was recommended with a comment that its use reduced the tendency of some fibrin to stain with the blue dye.


  1. Edward Gurr, 1971
    Synthetic dyes in biology, medicine and chemistry
    Academic Press, London, England.
  2. Bancroft, J.D. and Stevens A.
    Theory and practice of histological techniques Ed. 2
    Churchill Livingstone, Edinburgh & London, UK.