A red crystalline dye composed of the Potassium, Sodium, or Lead salt of tetrabromofluorescein. First discovered by Caro in 1871, eosin is primarily used as an acid dye for producing a blood red color in Silk, Wool, Paper, Leather, and Cotton. It is also used as a histological stain, a cosmetic colorant, and a colorant in red inks. In the late 19th and early 20th century, eosin was also used as a red paint pigment. Alcoholic solutions have a strong green Autofluorescence. Eosin is not permanent and fades rapidly in sunlight.
Synonyms and Related Terms
tetrabromofluorescein; Pigment Red 90; CI 45380; D&C Red No. 22; D&C Red No. 21; Acid Red 87; Solvent Red 43; éosine (Fr.); eosina (Esp., Port.); eosin Y; eosine A; eosine G; bromeosin; bromofluoresceic acid; geranium lake; eosine yellowish
Causes skin irritation. Fades rapidly in sunlight.
Physical and Chemical Properties
Soluble in ethanol. Insoluble in water (potassium and sodium salts of eosin are water soluble).
Maximum absorption wavelength = 520 nm.
Maximum emission wavelength = 540 nm.
|Molecular Weight||Mol. wt. = 647.9|
Resources and Citations
- M.Ballard (ed.), Important Early Synthetic Dyes. Chemistry, Constitution, Date, Properties. Conservation Analytical Laboratory, Smithsonian Institution, 1991.
- R. J. Gettens, G.L. Stout, Painting Materials, A Short Encyclopaedia, Dover Publications, New York, 1966
- Richard S. Lewis, Hawley's Condensed Chemical Dictionary, Van Nostrand Reinhold, New York, 10th ed., 1993
- Monona Rossol, The Artist's Complete Health and Safety Guide, Allworth Press, New York, 1994
- The Merck Index, Martha Windholz (ed.), Merck Research Labs, Rahway NJ, 10th edition, 1983 Comment: entry 3639
- Encyclopedia Britannica, http://www.britannica.com Comment: "Chemical Compound."(Accessed 12 May 2004).
- Website: www.probes.com/handbook/sections - gives absorption max=524 and emission max=544
- Website: member.pgonline.com/~bryand/dyes/45380.htm - absorption max = 516
- Colour Index International online at www.colour-index.org Comment: discoverer and date
- Sigma Dyes, Stains and Natural Pigments, Infrared Library, Nicolet, 1991-1995 Comment: OMNIC: formula= C20H8O5Br4, CAS= 548-26-5
- The American Heritage Dictionary or Encarta, via Microsoft Bookshelf 98, Microsoft Corp., 1998