Name: Congo Red *UltraPure grade* *CAS 573-58-0*
Brand: AAT Bioquest
SKU: 23056
Price: 90 USD
Availability: InStock

Congo Red

UltraPure grade; CAS 573-58-0

Congo red (CR) is the sodium salt of benzidinediazo-bis-1-naphtylamine-4-sulfonic acid. CR is water soluble, yielding a red colloidal solution. It is used to stain cytoplasm and erythrocyte stain in histology. Apple-green birefringence of CR stained preparates under polarized light is indicative for the presence of amyloid fibrils. Early diagnosis and classification of amyloid deposition and differentiation from other fibrillar deposits rely on routine CR-based histochemistry. This histology assay is widely used for the characterization of in vitro amyloid fibrils. In addition, CR is also used for fluorimetric examination of amyloid fibrils. Compared to CR in bright light CR fluorescence is simple to perform and more pronounced. Although not widely used, the CR fluorimetric method for detecting amyloid is simple to use with a high specificity and sensitivity, and may be applied successfully to frozen sections.

Catalog	Size	Price	Quantity
23056	100 mg	Price

Calculators

Common stock solution preparation

Table 1. Volume of Water needed to reconstitute specific mass of Congo Red *UltraPure grade* *CAS 573-58-0* to given concentration. Note that volume is only for preparing stock solution. Refer to sample experimental protocol for appropriate experimental/physiological buffers.

	0.1 mg	0.5 mg	1 mg	5 mg	10 mg
1 mM	143.542 µL	717.71 µL	1.435 mL	7.177 mL	14.354 mL
5 mM	28.708 µL	143.542 µL	287.084 µL	1.435 mL	2.871 mL
10 mM	14.354 µL	71.771 µL	143.542 µL	717.71 µL	1.435 mL

Molarity calculator

Enter any two values (mass, volume, concentration) to calculate the third.

Mass (Calculate)		Molecular weight		Volume (Calculate)		Concentration (Calculate)		Moles
mg	÷	696.66 g/mol	=	mL	x	mM	=	mmol

References

View all 53 references: Citation Explorer

The effects of sodium sulfate, glycosaminoglycans, and Congo red on the structure, stability, and amyloid formation of an immunoglobulin light-chain protein

Authors:

McLaughlin RW, De Stigter JK, Sikkink LA, Baden EM, Ramirez-Alvarado M.

Journal:

Protein Sci (2006): 1710

Acetylcholinesterase-amyloid-beta-peptide interaction: effect of Congo Red and the role of the Wnt pathway

Authors:

Inestrosa NC, Alvarez A, Dinamarca MC, Perez-Acle T, Colombres M.

Journal:

Curr Alzheimer Res (2005): 301

Alzheimer's beta-amyloid: insights into fibril formation and structure from Congo red binding

Authors:

Inouye H, Kirschner DA.

Journal:

Subcell Biochem (2005): 203

Improved detection of amyloid in fat pad aspiration: an evaluation of Congo red stain by fluorescent microscopy

Authors:

Giorgadze TA, Shiina N, Baloch ZW, Tomaszewski JE, Gupta PK.

Journal:

Diagn Cytopathol (2004): 300

Congo red populates partially unfolded states of an amyloidogenic protein to enhance aggregation and amyloid fibril formation

Authors:

Kim YS, R and olph TW, Manning MC, Stevens FJ, Carpenter JF.

Journal:

J Biol Chem (2003): 10842

Physical properties

Molecular weight	696.66
Solvent	Water

Spectral properties

Absorbance (nm)

195

Storage, safety and handling

Certificate of Origin	Download PDF
H-phrase	H303, H313, H333
Hazard symbol	XN
Intended use	Research Use Only (RUO)
R-phrase	R20, R21, R22
Storage	Freeze (< -15 °C); Minimize light exposure
UNSPSC	12352200
CAS	573-58-0

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Page updated on October 11, 2025