Neutral red

Neutral red
IUPAC name toluylene red
Other names 3-Amino-7-dimethylamino-2-methylphenazine hydrochloride
Identifiers
CAS number	553-24-2 Y
ChemSpider	10634 Y
Jmol-3D images	Image 1
SMILES Cl.n1c3c(nc2c1cc(c(c2)N)C)cc(N(C)C)cc3
InChI InChI=1S/C15H16N4.ClH/c1-9-6-13-15(8-11(9)16)18-14-7-10(19(2)3)4-5-12(14)17-13;/h4-8H,16H2,1-3H3;1H Y Key: PGSADBUBUOPOJS-UHFFFAOYSA-N Y InChI=1/C15H16N4.ClH/c1-9-6-13-15(8-11(9)16)18-14-7-10(19(2)3)4-5-12(14)17-13;/h4-8H,16H2,1-3H3;1H Key: PGSADBUBUOPOJS-UHFFFAOYAB
Properties
Molecular formula	C15H17ClN4
Molar mass	288.78 g/mol
Melting point	290°C
Boiling point	°C
Y (verify) (what is: Y/N?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Neutral red (pH indicator)
below pH 6.8		above pH 8.0
6.8	↔	8.0

Neutral Red (or toluylene red, Basic Red 5, or C.I. 50040) is a eurhodin dye used for staining in histology. It stains lysosomes red.^[1] It is used as a general stain in histology, as a counterstain in combination with other dyes, and for many staining methods. Together with Janus Green B, it is used to stain embryonal tissues and supravital staining of blood. Can be used for staining Golgi apparatus in cells and Nissl granules in neurons.

Neutral red can be used as a vital stain, to stain living cells. It is used to stain cell cultures for plate titration of viruses.

Neutral Red is added to some growth media for bacteria and cell cultures. It usually comes as a chloride salt.

Neutral Red acts as a pH indicator, changing from red to yellow between the pH 6.8-8.0.

References

1. ^ Winckler, J. Vital staining of lysosomes and other cell organelles of the rat with neutral Red. Prog. Histochem. Cytochem. 6, 1–89 (1974).