1977 Volume 18 Issue 5 Pages 463-469_1
An analytical method was investigated for the quantitative determination of water-soluble acid dyes permitted in Japan in foods by thin layer chromatography.
The presented method was composed for the following: The water-soluble acid dyes were extracted from foods with a liquid anion exchange resin (Amberlite LA-2), and washed with water. The dyes could be re-extracted from the resin solution by extracting with ammonia water. The dyes in the extracting solution was separated by thin layer chromatography using cellulose or silica gel plate. Each spot was scanned by the dual wave length and zig-zag scanning type densitometer.
The sensitivity limit of detection were 0.05μg of the dyes on the TLC plate.
The analytical conditions were as follows:
Slit; 1.25×1.25mm
Mode; Zig Zag scan
Wave length; Reference. λR=700nm
Sample. λS=a maximum wave length of each dyes
The recoveries of dyes added in juice, kamaboko (made from fish paste) and suhama (made from rice powder) were more than 93% except indigo carmine. As the results of the survey of commercial foods by the use of above mentioned procedure, concentration of dyes was used under about 100ppm in most of samples.
The presented method was found to be sufficiently satisfactory for quantitative determination of dyes in foods.
