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| INDIGO CARMINE |
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| SYNONYMS |
INDIGO CARMINE* C. I. FOOD BLUE 1 * FD & C BLUE 2 * INDIGOTINE * ACID BLUE 74 |
DEFINITION
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Indigo Carmine consists essentially of a mixture of disodium 3,3' dioxo - 2,2' -bi-indolylidene-5,5' - disulfonate, and disodium 3,3' - dioxo-2,2' - bi-indolyldene-5,7' -disulfonate and subsidary colouring matters together with sodium chloride and/or sodium sulfate as the principal uncoloured components.
Indigo Carmine is described as the sodium salt. The calcium and the potassium salt are also permitted. |
| CLASS |
Indigoid |
| COLOUR INDEX NO. |
73015 |
| EEC NUMBER |
E-132 |
| EINECS |
212-728-8 |
| CHEMICAL NAMES |
Disodium 3,3' -dioxo-2,2'-bi-indolylidene-5,5'-disulfonate |
| CHEMICAL FORMULA |
C16H8N2Na2O8S2 |
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| MOLECULAR WEIGHT |
466.36 |
| ASSAY |
Content not less than 85% total colouring matters, calculated as the sodium salt; disodium 3,3' -dioxo-2,2' -bi-indolylidene-5,7' -disulfonate : not more than 18% |
| DESCRIPTION |
Dark - blue powder |
IDENTIFICATION
a. Spectrometry
b. Blue solution in water |
Maximum in water at ca 610 nm . |
PURITY
Water Insoluble matter |
Not more than 0.2% |
Subsidiary colouring matters
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Excluding disodium 3,3' -dioxo-2,2' -bi-indolylidene-5,7' -disulfonate :not more than 1.0% |
| Organic compounds other than colouring matters |
[Isatin-5-sulfonic acid / 5-sulfoanthranilic acid / Anthranilic acid ] - Total not more than 0.5% |
| Unsulfonated primary aromatic amines |
Not more than 0.01% (Calculated as aniline) |
| Ether extractable matter |
Not more than 0.2% under neutral conditions |
| Arsenic |
Not more than 3 mg/kg. |
| Lead |
Not more than 10 mg/kg. |
| Mercury |
Not more than 1 mg/kg. |
| Cadmium |
Not more than 1 mg/kg. |
| Heavy metals (as Pb) |
Not more than 40 mg/kg. |
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