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C6767

Sigma-Aldrich

Congo Red

Dye content ≥35 %

Synonym(s):

Congo Red 4B, Cosmos Red, Cotton Red B, Cotton Red C, Direct Red 28, Direct Red R, Direct Red Y

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About This Item

Empirical Formula (Hill Notation):
C32H22N6Na2O6S2
CAS Number:
573-58-0
Molecular Weight:
696.66
Colour Index Number:
22120
Beilstein/REAXYS Number:
3894858
EC Number:
209-358-4
MDL number:
MFCD00004028
UNSPSC Code:
12171500
PubChem Substance ID:
24892892
NACRES:
NA.47

form

powder

Quality Level

200

composition

Dye content, ≥35%

technique(s)

titration: suitable

color

red-brown

pH

6.7 (10 g/L)

mp

>360 °C (lit.)

solubility

H2O: 1 mg/mL

application(s)

diagnostic assay manufacturing
hematology
histology

storage temp.

room temp

SMILES string

[Na+].[Na+].Nc1c(cc(c2ccccc12)S([O-])(=O)=O)\N=N\c3ccc(cc3)-c4ccc(cc4)\N=N\c5cc(c6ccccc6c5N)S([O-])(=O)=O

InChI

1S/C32H24N6O6S2.2Na/c33-31-25-7-3-1-5-23(25)29(45(39,40)41)17-27(31)37-35-21-13-9-19(10-14-21)20-11-15-22(16-12-20)36-38-28-18-30(46(42,43)44)24-6-2-4-8-26(24)32(28)34;;/h1-18H,33-34H2,(H,39,40,41)(H,42,43,44);;/q;2*+1/p-2/b37-35+,38-36+;;

InChI key

IQFVPQOLBLOTPF-HKXUKFGYSA-L

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Application

  • Congo red has been used as a histochemical stain for the quantification of amyloid deposits in brain tissues.
  • It has been used as a cell wall inhibiting agent in fungus Cryptococcus neoformans.
  • It has also been used to study microstructural details in the cell walls of raw potato and fried potato using confocal microscopy.

Biochem/physiol Actions

Congo red is a benzidine-based anionic diazo dye. It is a histological dye which binds to many amyloid proteins and is used for the quantification of amyloid β-peptide aggregation. Congo red also interacts with β-D-glucans, polysaccharides containing continuous β-(1→4)-linked D-glucopyranosyl units and some hemicellulosic galactoglucomannans.

pictograms

Health hazard
GHS08

signalword

Danger

Hazard Classifications

Carc. 1B - Repr. 2

Storage Class

6.1C - Combustible, acute toxic Cat.3 / toxic compounds or compounds which causing chronic effects

wgk_germany

WGK 3

ppe

Eyeshields, Gloves, type P3 (EN 143) respirator cartridges

Certificates of Analysis (COA)

Search for Certificates of Analysis (COA) by entering the products Lot/Batch Number. Lot and Batch Numbers can be found on a product’s label following the words ‘Lot’ or ‘Batch’.

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O A Odeyemi et al.
Microbial pathogenesis, 136, 103665-103665 (2019-08-14)
This study aimed to investigate antibiotic resistance and putative virulence factors among Cronobacter sakazakii isolated from powdered infant formula and other sources. The following 9 cultures (CR1-9) were collected from our culture collection: C. sakazakii and 3 Cronobacter species: C. sakazakii ATCC®
Some changes in potato chips during frying observed by confocal laser scanning microscopy (CLSM).
Pedreschi F and Aguilera JM
Food Science and Technology International = Ciencia y tecnologia de Los Alimentos Internacional, 8, 197-201 (2002)
Kinetic study and equilibrium isotherm analysis of Congo Red adsorption by clay materials.
Chemical Engineering Journal, 148, 354-364 (2009)
Quantification of cerebral amyloid angiopathy and parenchymal amyloid plaques with Congo red histochemical stain.
Wilcock DM, et al.
Nature Protocols, 1, 1591-1591 (2006)
PKC1 is essential for protection against both oxidative and nitrosative stresses, cell integrity, and normal manifestation of virulence factors in the pathogenic fungus Cryptococcus neoformans.
Gerik KJ, et al.
Eukaryotic Cell, 7, 1685-1685 (2008)
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