Indigo carmine

This article is about the blue dye derived from indigo. For the unrelated red dye, see Carmine. For other uses, see Carmine (disambiguation).

Indigo carmine
Names
Preferred IUPAC name
Disodium [2(2′)E]-3,3′-dioxo-1,1′,3,3′-tetrahydro[2,2′-biindolylidene]-5,5′-disulfonate
Other names
  • indigotine
  • 5,5′-indigodisulfonic acid sodium salt
  • Brilliant Indigo
  • 4 G
  • C.I. Acid Blue 74
  • C.I. 73015
  • CI Food Blue 1
  • FD&C Blue 2
  • Sicovit Indigotin 85
  • E132
  • indigotindisulfonate sodium
Identifiers
3D model (JSmol)
ChEBI
ChEMBL
ChemSpider
DrugBank
ECHA InfoCard 100.011.572 Edit this at Wikidata
EC Number
  • 212-728-8
E number E132 (colours)
KEGG
UNII
  • InChI=1S/C16H10N2O8S2.2Na/c19-15-9-5-7(27(21,22)23)1-3-11(9)17-13(15)14-16(20)10-6-8(28(24,25)26)2-4-12(10)18-14;;/h1-6,17-18H,(H,21,22,23)(H,24,25,26);;/q;2*+1/p-2/b14-13+;; checkY
    Key: KHLVKKOJDHCJMG-QDBORUFSSA-L checkY
  • InChI=1/C16H10N2O8S2.2Na/c19-15-9-5-7(27(21,22)23)1-3-11(9)17-13(15)14-16(20)10-6-8(28(24,25)26)2-4-12(10)18-14;;/h1-6,17-18H,(H,21,22,23)(H,24,25,26);;/q;2*+1/p-2/b14-13+;;
    Key: KHLVKKOJDHCJMG-AKPRSONXBD
  • [Na+].[Na+].[O-]S(=O)(=O)c3cc4C(=O)\C(=C2\C(=O)c1cc(ccc1N2)S([O-])(=O)=O)Nc4cc3
Properties
C16H8N2Na2O8S2
Molar mass 466.36 g/mol
Appearance purple solid
Melting point >300 °C (572 °F)
10 g/L (25 °C (77 °F))
Hazards
GHS labelling:
GHS07: Exclamation mark[1]
Warning
H302[1]
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g. chloroformFlammability 1: Must be pre-heated before ignition can occur. Flash point over 93 °C (200 °F). E.g. canola oilInstability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
2
1
0
Pharmacology
V04CH02 (WHO)
Legal status
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
☒N verify (what is checkY☒N ?)
Indigotindisulfonate sodium
Clinical data
Trade namesBludigo
License data
Identifiers
E numberE132 (colours) Edit this at Wikidata
CompTox Dashboard (EPA)
ECHA InfoCard100.011.572 Edit this at Wikidata

Indigo carmine, or 5,5′-indigodisulfonic acid sodium salt, is an organic salt derived from indigo by aromatic sulfonation, which renders the compound soluble in water. Like indigo, it produces a blue color, and is used in food and other consumables, cosmetics, and as a medical contrast agent and staining agent; it also acts as a pH indicator. It is approved for human consumption in the United States and European Union.[3][4] It has the E number E132, and is named Blue No. 2 by the US Federal Food, Drug, and Cosmetic Act.

  1. ^ a b "Indigo carmine". Sigma Aldrich. Retrieved 15 Feb 2022.
  2. ^ "Bludigo- indigotindisulfonate sodium injection". DailyMed. 7 November 2022. Retrieved 21 January 2023.
  3. ^ Summary of Color Additives for Use in United States in Foods, Drugs, Cosmetics, and Medical Devices, Food and Drug Administration
  4. ^ Current EU approved additives and their E Numbers, Food Standards Agency, 26 November 2010