Eosin
Eosin is the name of several
Etymology
Eosin was named by its inventor Heinrich Caro after the nickname (Eos) of a childhood friend, Anna Peters.[3]
Variants
There are actually two very closely related compounds commonly referred to as eosin. Most often used is in histology is Eosin Y[1][2] (also known as eosin Y ws, eosin yellowish, Acid Red 87, C.I. 45380, bromoeosine, bromofluoresceic acid, D&C Red No. 22); it has a very slightly yellowish cast. The other eosin compound is Eosin B (eosin bluish, Acid Red 91, C.I. 45400, Saffrosine, Eosin Scarlet, or imperial red); it has a very faint bluish cast. The two dyes are interchangeable, and the use of one or the other is a matter of preference and tradition.
Eosin Y is a tetrabromo derivative of fluorescein.[4] Eosin B is a dibromo dinitro derivative of fluorescein.[5]
Uses
Use in histology
Eosin is most often used as a
For staining, eosin Y is typically used in concentrations of 1 to 5 percent weight by volume, dissolved in water or ethanol.[6] For prevention of mold growth in aqueous solutions, thymol is sometimes added.[7] A small concentration (0.5 percent) of acetic acid usually gives a deeper red stain to the tissue.
It is listed as an
Other uses
Eosin is also used as a red dye in inks; however, the molecule, especially that of eosin Y, tends to degrade over time, leaving behind its bromine atoms, hence causing paint incorporating such a dye to obtain a darker brown tinge over time.
See also
References
- ^ a b Lillie, Ralph Dougall (1977). H. J. Conn's Biological stains (9th ed.). Baltimore: Williams & Wilkins. pp. 692p.
- ^ a b Bancroft, John; Stevens, Alan, eds. (1982). The Theory and Practice of Histological Techniques (2nd ed.). Longman Group Limited.
- JSTOR 3107005.
- SMILESstructure is O=C5C(Br)=C2O C1=C(Br)C([O-]) =C(Br)C=C1C(C4=C (C([O-])=O)C=C C=C4)=C2C=C3Br.
- SMILESstructure is O=C5C(Br)=C2O C1=C(Br)C([O-]) =C([N+]([O-])=O) C=C1C(C4=C(C([O-]) =O)C=CC=C4)=C2 C=C3[N+]([O-])=O.
- ^ "Haematoxylin Eosin (H&E) staining". protocolsonline.com. 11 April 2010. Retrieved 22 April 2018.
- PMID 6769391.
- ^ a b "Van Gogh's Fading Colors Inspire Scientific Inquiry".