Bismarck brown Y also called C.I. 21000 and C.I. Basic Brown 1, is a

diazo dye Azo dyes are organic compounds bearing the functional group R−N=N−R′, in which R and R′ are usually aryl and substituted aryl groups. They are a commercially important family of azo compounds, i.e. compounds containing the C-N=N ...

with the idealized formula H₂N)₂C₆H₃N₂sub>2C₆H₄. The dye is a mixture of closely related compounds. It was one of the earliest azo dyes, being described in 1863 by German chemist

Carl Alexander von Martius Carl Alexander von Martius (born January 19, 1838, in Munich; died February 26, 1920, in Nonn by Bad Reichenhall) was a German chemist and entrepreneur. Life His father was botanist and explorer Carl Friedrich Philipp von Martius (1794–18 ...

. It is used in

histology Histology, also known as microscopic anatomy or microanatomy, is the branch of biology which studies the microscopic anatomy of biological tissues. Histology is the microscopic counterpart to gross anatomy, which looks at larger structures vi ...

for staining tissues.

Synthesis

The dye is simple to prepare because the diamine serves both as a source of the diazonium cation and as the coupling partner in the azo coupling reaction. The synthesis is thought to start with double

diazotization Diazonium compounds or diazonium salts are a group of organic compounds sharing a common functional group where R can be any organic group, such as an alkyl or an aryl, and X is an inorganic or organic anion, such as a halide. General propert ...

of 1,3-phenylenediamine: :(H₂N)₂C₆H₄ + 2 H⁺ + 2 HNO₂ → ₆H₄(N₂)₂sup>2+ + 2 H₂O It is assumed that this bis(diazonium) ion subsequently attacks two equivalents of 1,3-phenylenediamine: :2 (H₂N)₂C₆H₄ + ₆H₄(N₂)₂sup>2+ → 2 H⁺ + H₂N)₂C₆H₃N₂sub>2C₆H₄ In some cases,

toluenediamine Toluenediamine may refer to these isomeric organic compounds with the formula C6H3(NH2)2(CH3): *2,4-Diaminotoluene, precursor to toluene diisocyanate and azo dye Azo dyes are organic compounds bearing the functional group R−N=N−R� ...

s are used in addition to the phenylenediamine. Furthermore, the resulting dye is thought to consist of oligomers with three or more diazo groups.

Uses

Bismarck brown Y stains acid

mucin Mucins () are a family of high molecular weight, heavily glycosylated proteins (glycoconjugates) produced by epithelial tissues in most animals. Mucins' key characteristic is their ability to form gels; therefore they are a key component in most ...

s to yellow color. It also stains

mast cell A mast cell (also known as a mastocyte or a labrocyte) is a resident cell of connective tissue that contains many granules rich in histamine and heparin. Specifically, it is a type of granulocyte derived from the myeloid stem cell that is a par ...

granules brown. It can be used with live cells. It is also used to stain cartilage in

bone A bone is a rigid organ that constitutes part of the skeleton in most vertebrate animals. Bones protect the various other organs of the body, produce red and white blood cells, store minerals, provide structure and support for the body, ...

specimens, as one of Kasten's Schiff-type reagents in the

periodic acid-Schiff stain Periodicity or periodic may refer to: Mathematics * Bott periodicity theorem, addresses Bott periodicity: a modulo-8 recurrence relation in the homotopy groups of classical groups * Periodic function, a function whose output contains values tha ...

to stain

cellulose Cellulose is an organic compound with the formula , a polysaccharide consisting of a linear chain of several hundred to many thousands of β(1→4) linked D-glucose units. Cellulose is an important structural component of the primary cell w ...

, and in

Feulgen stain Feulgen stain is a staining technique discovered by Robert Feulgen and used in histology to identify chromosomal material or DNA in cell specimens. It is darkly stained. It depends on acid hydrolysis of DNA, therefore fixating agents using stron ...

to stain DNA. It was more common in the past; today it is partially replaced by other stains. It has also been used to give soap an amber color in the past. Bismarck brown Y is a constituent of

Papanicolaou stain Papanicolaou stain (also Papanicolaou's stain and Pap stain) is a multichromatic (multicolored) cytological staining technique developed by George Papanicolaou in 1942. The Papanicolaou stain is one of the most widely used stains in cytology, w ...

. It can also be used as a

counterstain A counterstain is a stain with colour contrasting to the principal stain, making the stained structure easily visible using a microscope. Examples include the malachite green counterstain to the fuchsine stain in the Gimenez staining technique ...

for Victoria blue R for staining of

acid-fast Acid-fastness is a physical property of certain bacterial and eukaryotic cells, as well as some sub-cellular structures, specifically their resistance to decolorization by acids during laboratory staining procedures. Once stained as part of a sam ...

microorganisms.

References

{{Reflist, refs= {{cite book , last1=Lillie , first1=Ralph Dougall , title=H. J. Conn's Biological stains , date=1977 , publisher=Williams & Wilkins , location=Baltimore , pages=692p , edition=9th Azo dyes Vital stains