Acid Red 87 (Eosin Y) is a red crystalline/xanthene dye with excellent tinting strength and strong visible absorption in the green region (typical λmax ≈ 515–519 nm in ammonium acetate solution). It is supplied as the sodium/potassium salt or as the free acid depending on the supplier and intended application. The dye is widely used for biological staining (histology/cytology), red inks, leak detection/non-destructive testing, cleaning products and some textile/leather applications where an acid dye is appropriate. Typical physical form is a red to orange powder that dissolves readily in water or alcohol depending on the salt form.
TRADE NAME:Eosine Y,Weak Acid Red A,Weak Acid scarlet,Eosine Yellowish
Standard | Fiber | Soaping | Persperation Fastness | Oxygen bleaching | Light | |
Fading | Stain | |||||
AATCC | Wool | 2 | 2 | 3 | 1 | 1 |
ISO | Wool | 3 | 3 | 2 | 1-2 | 2 |
Leveling(grade) |
Displacement |
Whitening |
Solubility(g/L) | Metal ion effect(grade) | ||
copper | iron | chromium | ||||
3~4 | — | bad | — | 3~4 | 4 | — |
Test Methods | fiber | Alkali resistance | Carbonization | Chlorination discoloration | Oxygen bleaching | Alkali fluff | Acid fluff | potting | soaping | Perspiration | Sun exposure | ||||
discolor | Staining | discolor | Staining | discolor | Staining | discolor | Staining | ||||||||
AATCC | wool | 3 | 3 | — | 1 | 2 | 2 | — | — | — | — | 2 | 2 | 3 | 1 |
ISO | wool | 2 | 2 | 2 | 1 | 1 | 1 | 2 | 1 | 1 | 1 | 3 | 3 | 2 | 2 |
Mainly used in red ink and red pencils, only comfortable carpet dyeing. After refining can be used as medicine and cosmetics of coloring. Can also be used in leather dyeing. The aluminum salt can be used as organic pigments.
The salt forms (sodium/potassium) are far more water-soluble and are typically used where rapid dissolution is required (inks, leak tracers, detergents). The free acid form is less soluble and is sometimes used when slower release or different substrate affinity is desired. Choose the salt for aqueous formulations and the acid form only if the formulation specifically requires it.
Typical usage is highly application-dependent: industrial cleaning products and detergents often use very low ppm (e.g. 0.001% by weight), non-destructive testing/leak tracing uses slightly higher doses (0.01–0.1% typical), and inks or laboratory stains are formulated to the shade and optical density required. Always run pilot trials to confirm shade and fastness at your production scale.
Acid Red 87 can shift shade or precipitate in the presence of strong metal salts; some suppliers note color change with iron or copper. For formulations with metal content, pre-screen for shade stability and consider chelating agents or formulation adjustments to avoid unwanted color shifts.
Yes — Eosin Y (C.I. Acid Red 87) is the standard eosin counterstain in H&E preparations. If substituting suppliers, match dye strength (lot variability) and run staining controls because brightness and contrast can vary by batch and salt form.
Store in a cool, dry place in tightly closed containers away from strong oxidizers and direct sunlight. Keep powder forms under conditions that minimize dust formation and moisture. Typical shelf life varies by formulation and packaging but many vendors quote 1–3 years if stored correctly—confirm with your supplier.
Because the dye is persistent in color and may be biologically active, industrial wastewater should be treated with appropriate dye removal processes (adsorption, advanced oxidation, biological treatment tailored to azo/xanthene dyes). Follow local discharge regulations and supplier SDS guidance for disposal. Pilot a wastewater treatment path for your exact effluent composition.
