AZORUBINE
Prepared at the 28th JECFA (1984), published in FNP 31/1 (1984) and in FNP 52 (1992). Metals and arsenic specifications revised at the 59th JECFA (2002). An ADI of 0-4 mg/kg bw was established at the 27th JECFA (1983) SYNONYMS CI Food Red 3, Carmoisine, CI (1975) No. 14720, INS No. 122 DEFINITION Consists essentially of disodium 4-hydroxy-3-(4-sulfonato-1-naphthylazo)1-naphthalenesulfonate and subsidiary colouring matters together with sodium chloride and/or sodium sulfate as the principal uncoloured components. May be converted to the corresponding aluminium lake in which case only the General Specifications for Aluminium Lakes of Colouring Matters shall apply. Chemical names Disodium 4-hydroxy-3-(4-sulfonato-1-naphthylazo)-1-naphthalenesulfonate C.A.S. number 3567-69-9 Chemical formula C20H12N2Na2O7S2
Structural formula
Formula weight 502.44 Assay Not less than 85% total colouring matters DESCRIPTION Red powder or granules FUNCTIONAL USES Colour CHARACTERISTICS IDENTIFICATION Solubility (Vol. 4) Soluble in water, sparingly soluble in ethanol
Identification of colouring matters (Vol. 4)
Passes test
PURITY Loss on drying (Vol. 4) Not more than 15% at 135° together with chloride and sulfate calculated as sodium salts
Water insoluble matter (Vol. 4)
Not more than 0.2%
Lead (Vol. 4) Not more than 2 mg/kg Determine using an atomic absorption technique appropriate to the specified level. The selection of sample size and method of sample preparation may be based on the principles of the method described in Volume 4, “Instrumental Methods.”
Subsidiary colouring matters (Vol. 4)
Not more than 1% Use the following conditions: Developing solvent: No. 4 Height of ascent of solvent front: approximately 17 cm
Organic compounds other than colouring matters (Vol. 4)
Not more than 0.5% of 4-Amino-1-naphthalenesulfonic acid and 4-Hydroxy-1-naphthalenesulfonic acid together Use HPLC under the following conditions: HPLC elution gradient: 1 to 100% at 2.0% per min (exponential)
Unsulfonated primary aromatic amines (Vol. 4)
Not more than 0.01% calculated as aniline of
Ether extractable matter (Vol. 4)
Not more than 0.2%
METHOD OF ASSAY Proceed as directed under Total Content by Titration with Titanous Chloride in Volume 4, using the following: Weight of sample: 0.5 - 0.6 g Buffer: 15 g sodium hydrogen tartrate Weight (D) of colouring matters equivalent to 1.00 ml of 0.1 N TiCl3: 12.56 mg