Abstract
A generally applicable method for the determination of organic impurities as well as the main dyes in 11 kinds of food coal-tar dyes (Amaranth, Erythrosine, New Coccine, Phloxine, Rose Bengal, Acid Red, Tartrazine, Sunset Yellow FCF, Fast Green FCF, Brilliant Blue FCF, Indigo Carmine) was developed by employing high performance liquid chromatography. A reverse phase partition type column was used with a gradient elution system formed from 1% ammonium acetate solution (pH 8.0) and 20% acetonitrile in methanol. The peak areas were determined by a micro computer attached to the detector. Contents of organic impurities were expressed as total amount of colorless organic impurities (starting materials residues, uncombined intermediates, etc.) and total amount of subsidiary dyes. By the use of the proposed method, a survey of colorless organic impurities, subsidiary dyes and main dyes was carried out on 46 samples of food coal-tar dyes produced in 1982.
