Description

Eosin B CAS NO 548-24-3 is a synthetic red dye belonging to the xanthene class, widely recognized as a biological stain and colorant. Its core value lies in its strong affinity for cytoplasmic components and its utility as a counterstain in histological procedures, providing critical visual contrast for microscopic analysis. This product is essential for professionals in histology, cytology, and textile dyeing, where consistent color quality and staining performance are paramount.

Application

• Histological Staining: Primarily used as a counterstain in combination with hematoxylin (H&E staining variants) to differentiate cytoplasmic and connective tissue elements.
• Cytological Analysis: Employed in Pap smears and other cytological preparations to stain cell cytoplasm, aiding in the identification of cellular structures.
• Textile Dyeing: Functions as a colorant for silk, wool, and nylon fibers, imparting a distinctive red hue.
• Ink Manufacturing: Used in the formulation of red inks for specialized printing applications.
• Biological Research: Utilized as a fluorescent tracer and vital stain in various experimental protocols.
• Paper and Leather Coloring: Applied as a dye for coloring paper products and leather goods.

Basic Information

Product Name	Eosin B
CAS No.	548-24-3
Molecular Formula	C20H6Br4Na2O5
Molecular Weight	624.0 g/mol
Synonyms	Acid Red 91; Eosin Scarlet; Eosin B bluish; C.I. 45400; Bromoeosin; D&C Red No. 21; Eosin B sodium salt; 2',4',5',7'-Tetrabromo-3',6'-dihydroxyspiro[isobenzofuran-1(3H),9'-[9H]xanthen]-3-one disodium salt
EINECS	208-961-0

Quality Control

Our Eosin B is produced under a stringent quality management system to ensure batch-to-batch consistency and performance reliability for critical applications. Each lot is tested against rigorous in-house specifications for purity, color strength, and solubility. A comprehensive Certificate of Analysis (COA) detailing identity, assay, and impurity profiles is provided with every shipment to support your quality assurance protocols.

Storage

Preserve in a tightly closed container, protected from light. Store in a cool, dry, and well-ventilated area at room temperature (15-25°C). Keep away from incompatible materials.

Specification

Item	Specification
Appearance	Red to brownish-red powder
Identification (IR)	Conforms to structure
Assay (HPLC)	≥ 85.0% (Dye content)
Loss on Drying	≤ 10.0 %
Solubility (in Water)	Passes test
pH (1% Solution)	7.0 - 9.0
Heavy Metals (as Pb)	≤ 20 ppm

Note: Specifications can be tailored. Please contact us for the detailed technical data sheet of a specific grade.