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Naphthalene Blue Black

Naphthalene Blue Black

Class: Azo
Ionisation: Acid

Chemical structure of Naphthalene Blue Black

Common Name: Naphthalene blue black CS
Suggested Name: Naphthalene blue black CS
Other Names:

Blauschwartz NSF

C.I. Number: 20480
C.I. Name: Acid black 41
Color: Blue black
Solubility Aqueous: Freely
Solubility Ethanol: Freely
Absorption Maximum: 610-614
Empirical Formula: C22H13N6O12S3Na3
Formula Weight: 719


Lendrum used this dye for the demonstration of fibrin in his Masson 44/41 and Obadiah methods. He considered that it demonstrated the oldest fibrin at a stage when it was not distinguishable from collagen by any other staining method.

The dye is not easily available, and not used in any other procedures than Lendrum's Masson 44/41 and Obadiah, both for old fibrin. Naphthol blue black, otherwise known as amido black 10B, CI 20470, is closely related and may be a suitable substitute.


  1. Edward Gurr, 1971
    Synthetic dyes in biology, medicine and chemistry
    Academic Press, London, England.