Eosin
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218698070
2008-06-11T19:56:03Z
Eubot
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Hatnote formatting, see [[User:Eubot/Hatnote formatting]]
{{for|the eosin glazing process|Zsolnay}}
{{Mergefrom|Eosinophilic|date=July 2007}}
[[Image:Eosin Y.png|thumb|right|200px|Eosin Y]]
[[Image:Eosin B.png|thumb|right|200px|Eosin B]]
'''Eosin''' is a [[fluorescent]] red [[dye]] resulting from the action of [[bromine]] on [[fluorescein]]. It can be used to stain [[cytoplasm]], [[collagen]] and [[Muscle#Muscular Composition|muscle fibers]] for examination under the [[microscope]].
There are actually two very closely related compounds commonly referred to as eosin. Most often used is '''eosin Y''' (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 is most often used as a [[counterstain]] to [[haematoxylin]] in [[H&E stain|H&E (haematoxylin and eosin) staining]]. H&E staining is one of the most commonly used techniques in [[histology]]. [[biological tissue|Tissue]] stained with [[hematoxylin]] and eosin shows [[cytoplasm]] stained pink-orange and [[cell nucleus|nuclei]] stained darkly, either blue or purple. Eosin also stains [[erythrocyte|red blood cells]] intensely red. Eosin is an acidic dye and shows up in the basic parts of the cell, ie the cytoplasm. [[Hematoxylin]] however is a basic dye and shows up in the acidic part of the cell. For example the nucleus, where [[nucleic acids]] ([[DNA]] and [[RNA]]) are concentrated.
Structures that stain readily with eosin are termed [[eosinophilic]].
Eosin Y is a tetrabromo derivate of [[fluorescein]]. {{SMILESCAS|CAS=17372-87-1|SMILES=O=C5C(Br)=C2O C1=C(Br)C([O-]) =C(Br)C=C1C(C4=C (C([O-])=O)C=C C=C4)=C2C=C3Br}}
Eosin B is a dibromo dinitro derivate of [[fluorescein]]. {{SMILESCAS|CAS=548-28-3|SMILES=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}}
==Recipes for [[Histology]]==
==='''5% Aqueous Eosin Y'''===
'''Formula:'''
* 5 g Eosin Y
* 100 mL Distilled water
Dissolve Eosin Y crystals in water by gentle heating. Cool and Filter. [[Thymol]] crystals may be added to prevent formation of molds.
==='''Eosin, Stock Alcoholic Solution'''===
'''Formula:'''
* 1 g Eosin Y
* 20 mL Distilled water
* 95% Alcohol
Dissolve Eosin Y in the water by gentle heating. Cool and add Alcohol.
For use, one part of the stock solution is usually diluted with three parts of 80% Alcohol. Addition of 0.5 mL Glacial [[Acetic Acid]] (HOAc) for every 100 mL of stain will usually give a deeper red stain to the tissue.
==Etymology==
The name Eosin comes from [[Eos]], the Greek word for 'dawn' and the name of the Greek Goddess of the Dawn.[http://www.m-w.com/dictionary/eosin]
==See also==
* [[Hematoxylin]]
* [[H&E stain]]
==External links==
*[http://www.abbeycolor.com/eosin-y.php Eosin Y - Applications information]
==References==
*Jocelyn H. Bruce-Gregorios, M.D.: Histopathologic Techniques, JMC Press Inc., Quezon City, Philippines, 1974.
{{Antiseptics and disinfectants}}
[[Category:Fluorone dyes]]
[[Category:Staining dyes]]
[[de:Eosin]]
[[es:Eosina]]
[[fr:Éosine]]
[[it:Eosina]]
[[hu:Eozin (festék)]]
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[[pl:Eozyna]]
[[pt:Eosina]]
[[ru:Эозин]]
[[sv:Eosin]]
[[tr:Eozin]]