Allura Red consists essentially of disodium 2-hydroxy-1-(2-methoxy-5-methyl-4-sulfonato-phenylazo) nephthalene-6-sulfonate and subsidiary colouring matters together with sodium chloride and/or sodium sulfate as the principal uncoloured components.
Allura Red is described as the sodium salt. The calcium and the potassium salt are also permitted.
Content not less than 85% total colouring matters, calculated as the sodium salt;
E 1% 1cm 540 at ca 504 nm in aqueous solution at pH7
DESCRIPTION
Dark red powder
IDENTIFICATION
a. Spectrometry
b. Red solution in water
Maximum in water at ca 504 nm
PURITY
Water Insoluble matter
Not more than 0.2%
Subsidiary colouring matters
Not more than 3.0%
Organic compounds other than colouring matters
[6-hydroxy-2-naphthalene sulfonic acid, sodium salt] - Not more than 0.3%
[4-amino-5-methoxy-2-methylbenezene sulfonic acid] - Not more than 0.2%
[6,6-oxybis (2-naphthalene sulfonic acid) disodium salt] - Not more than 0.1%
