Modification of HPLC conditions for the determinations of raw materials, intermediates and subsidiary colors in 5 kinds of food azo colors

Modification of HPLC conditions for the determinations of raw materials, in termediates and subsidiary colors (organic impurities) in 5 kinds of food a zo colors were studied in order to analyze them simply and rapidly. The org anic impurities were determined by HPLC using L-column ODS and a gradient s ystem (0.02 mol/L ammonium acetate solution for 10 min, and a gradient with a mixture of acetonitrile and water (7:3)). The organic impurities in 163 samples of azo colors subjected to inspection in fiscal year 1999 were dete rmined under the proposed HPLC conditions. It was found that the contents o f organic impurities in 163 samples were less than the limit of Japan's Spe cifications and Standards for Food Additives, 7th Edition.