Water blue

For the butterfly with this common name, see Cacyreus tespis.

Water blue, also known as aniline blue, Acid blue 22, Soluble Blue 3M, Marine Blue V, or C.I. 42755, is a chemical compound used as a stain in histology. Water supply blue stains collagen blue in tissue sections. It is soluble in water and slightly soluble in ethanol.

Water blue

Identifiers
CAS Number	28631-66-5 Y
3D model (JSmol)	Interactive image
ChemSpider	21173243
ECHA InfoCard	100.044.634
EC Number	249-113-9
PubChem CID	139030972
UNII	44D829LK4D Y
CompTox Dashboard (EPA)	DTXSID9044904
InChI InChI=1S/C32H27N3O9S3.2Na/c33-20-26-25(6-5-11-29(26)45(36,37)38)32(21-12-16-23(17-13-21)34-27-7-1-3-9-30(27)46(39,40)41)22-14-18-24(19-15-22)35-28-8-2-4-10-31(28)47(42,43)44;;/h1-19,34H,20,33H2,(H,36,37,38)(H,39,40,41)(H,42,43,44);;/q;2*+1/p-2 Key: WJHQBPPQVMBLSW-UHFFFAOYSA-L
SMILES [H+].c1ccc(c(c1)Nc2ccc(cc2)C(=C3C=CC(=Nc4ccccc4S(=O)(=O)[O-])C=C3)c5cccc(c5CN)S(=O)(=O)[O-])S(=O)(=O)[O-].[Na+].[Na+]
Properties
Chemical formula	C32H25N3O9S3Na2
Molar mass	737.72374 g/mol
Hazards
GHS labelling:
Pictograms
Signal word	Warning
Hazard statements	H315, H317, H319, H335
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Y verify (what is YN ?) Infobox references

Water blue is also available in mixture with methyl blue, under the names Aniline Blue WS, Aniline blue, China blue, or Soluble blue.^[1][2]

It can be used in the Mallory's trichrome stain of connective tissue and Gömöri trichrome stain of muscle tissue. It is used in differential staining.^[3]

See also

• RAL 5021 Water blue