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'''Indigo carmine''', or '''5,5′-indigodisulfonic acid sodium salt''', also known as '''indigotine''' or '''FD&C Blue #2''', is a [[pH indicator]] with the [[chemical formula]] [[Carbon|C]]<sub>16</sub>[[Hydrogen|H]]<sub>8</sub>[[Nitrogen|N]]<sub>2</sub>[[Sodium|Na]]<sub>2</sub>[[Oxygen|O]]<sub>8</sub>[[Sulfur|S]]<sub>2</sub>. It is approved for use as a [[Food coloring|food colorant]] in the United States<ref name="FDA colors">[http://www.fda.gov/ForIndustry/ColorAdditives/ColorAdditiveInventories/ucm115641.htm Summary of Color Additives for Use in United States in Foods, Drugs, Cosmetics, and Medical Devices], [[United States Food and Drug Administration]]</ref> and in Europe |
'''Indigo carmine''', or '''5,5′-indigodisulfonic acid sodium salt''', also known as '''indigotine''' or '''FD&C Blue #2''', is a [[pH indicator]] with the [[chemical formula]] [[Carbon|C]]<sub>16</sub>[[Hydrogen|H]]<sub>8</sub>[[Nitrogen|N]]<sub>2</sub>[[Sodium|Na]]<sub>2</sub>[[Oxygen|O]]<sub>8</sub>[[Sulfur|S]]<sub>2</sub>. It is approved for use as a [[Food coloring|food colorant]] in the United States<ref name="FDA colors">[http://www.fda.gov/ForIndustry/ColorAdditives/ColorAdditiveInventories/ucm115641.htm Summary of Color Additives for Use in United States in Foods, Drugs, Cosmetics, and Medical Devices], [[United States Food and Drug Administration]]</ref> and in Europe,<ref name=FSAlist>[http://www.food.gov.uk/safereating/chemsafe/additivesbranch/enumberlist Current EU approved additives and their E Numbers], [[Food Standards Agency]], 26 November 2010</ref> and has the [[E number]] '''E132'''. |
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==Uses== |
==Uses== |
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Revision as of 00:39, 7 July 2016
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| Names | |
|---|---|
| IUPAC name
3,3′-dioxo-2,2′-bisindolyden-5,5′-disulfonic acid disodium salt
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| Other names
indigotine
5,5′-indigodisulfonic acid sodium salt | |
| Identifiers | |
3D model (JSmol)
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| ChEBI | |
| ChemSpider | |
| ECHA InfoCard | 100.011.572 |
| E number | E132 (colours) |
PubChem CID
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| UNII | |
CompTox Dashboard (EPA)
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| 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: | |
 [1]
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| Warning | |
| H302[1] | |
| NFPA 704 (fire diamond) | |
| Pharmacology | |
| V04CH02 (WHO) | |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Indigo carmine, or 5,5′-indigodisulfonic acid sodium salt, also known as indigotine or FD&C Blue #2, is a pH indicator with the chemical formula C16H8N2Na2O8S2. It is approved for use as a food colorant in the United States[2] and in Europe,[3] and has the E number E132.
Uses
| Indigo Carmine (pH indicator) | ||
| below pH 11.4 | above pH 13.0 | |
| 11.4 | ⇌ | 13.0 |
Indigo carmine is commonly used as a pH indicator, often in a 0.2% aqueous solution. It is blue at pH 11.4 and yellow at 13.0. Indigo carmine is also a redox indicator, turning yellow upon reduction. Another use is as a dissolved ozone indicator[4] through the conversion to isatin-5-sulfonic acid.[4] This reaction has been shown not to be specific to ozone, however: it also detects superoxide, an important distinction in cell physiology.[5] It is also used as a dye in the manufacturing of capsules.
In obstetric surgery, indigo carmine solutions are sometimes employed to detect amniotic fluid leaks. In urologic surgery, intravenous injection of indigo carmine is often used to highlight portions of the urinary tract. The dye is filtered rapidly by the kidneys from the blood, and colors the urine blue. This enables structures of the urinary tract to be seen in the surgical field, and demonstrate if there is a leak. However, the dye can cause a potentially dangerous increase in blood pressure in some cases.[6]
Health concerns
Indigo carmine is harmful to the respiratory tract if inhaled. It is also an irritant to the skin and eyes. Proper laboratory cautions (lab coat, gloves, goggles) are advised.
See also
References
- ^ a b "Indigo carmine". Sigma Aldrich. Retrieved 10 March 2016.
- ^ Summary of Color Additives for Use in United States in Foods, Drugs, Cosmetics, and Medical Devices, United States Food and Drug Administration
- ^ Current EU approved additives and their E Numbers, Food Standards Agency, 26 November 2010
- ^ a b Takeuchi K, Ibusuki T (March 1989). "Quantitative determination of aqueous-phase ozone by chemiluminescence using indigo-5,5'-disulfonate". Anal. Chem. 61 (6): 619–23. doi:10.1021/ac00181a025. PMID 2729594.
- ^ Kettle AJ, Clark BM, Winterbourn CC (April 2004). "Superoxide converts indigo carmine to isatin sulfonic acid: implications for the hypothesis that neutrophils produce ozone". J. Biol. Chem. 279 (18): 18521–5. doi:10.1074/jbc.M400334200. PMID 14978029.
{{cite journal}}: CS1 maint: unflagged free DOI (link) - ^ Craik, Johnathan Donaldson (January–February 2009). "The Safety of Intravenous Indigo Carmine to Assess Ureteric Patency During Transvaginal Uterosacral Suspension of the Vaginal Vault". Journal of Pelvic Medicine & Surgery. 15 (1): 11–15. doi:10.1097/SPV.0b013e3181986ace. Retrieved 18 October 2012.