Congo red, powder

Supplier: MP BIOMEDICALS (FKA ICN BIOMED
Danger

Synonyms: CI 22120

0210509925 0210509990 0210509980
IC10509925EA 34.02 USD
IC10509925 IC10509990 76102-650
Congo red, powder
Congo red

Congo red is the sodium salt of 3,3'-([1,1'-biphenyl]-4,4'-diyl)bis(4-aminonaphthalene-1-sulfonic acid). It is a secondary diazo dye. It is absorption indicator for halide and thiocyanate determinations.


  • UV/Visible Absorbance : λ max (water): 497 ± 3nm
  • Presentation : Red Powder
  • pH : Visual Transition Interval: From pH 3.0 (blue) to pH 5.2 (red).
  • Solubility : Soluble in water,ethanol; very slightly soluble in acetone; practically insoluble in ether; slightly soluble in acetic acid.


Visual Transition Interval: From pH 3.0 (blue) to pH 5.2 (red).


In biochemistry and histology, congo red is used to stain microscopic preparates, especially as a cytoplasm and erythrocyte stain. It is used for the visual detection of amyloid in muscle and nerve fresh frozen sections in patients who have amyloidosis. Apple-green birefringence of Congo red stained preparates under polarized light is indicative for the presence of amyloid fibrils. Additionally, congo red is used in microbiological epidemiology to rapidly identify the presence of virulent serotype 2a Shigella flexneri, where the dye binds the bacterium's unique lipopolysaccharide (LPS) structure.

Formula: C₃₂H₂₂N₆Na₂O₆S₂
MW: 696.67 g/mol
Melting Pt: >360 °C (lit.)
Storage Temperature: Ambient
MDL Number: MFCD00004028
CAS Number: 573-58-0
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Specification Test Results

Identity Test Passes
UV/Vis: l max (water) 497 ± 3nm

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