[Determination and survey of starting materials, intermediates, and subsidiary colors in food color of azo dye by high performance liquid chromatography].

A method for determination of starting materials, intermediates and subsidiary colors in food color of azo dye was developed by use of HPLC. The following conditions were used for analysis: column, L-column ODS (4.6 mm phi x 250 mmL); mobile phase, 0.02 M ammonium acetate (A), acetonitrile (B); concentration gradient, perform the linear concentration gradient from A:B (100:0) to (60:40) for 40 min; detection, starting materials and intermediates at 239 nm, and subsidiary colors at 510 nm. Standard material, domestic product and imported product were analyzed by the present HPLC method and impurities were measured. Recoveries of each impurity from azo dye averaged 99.1-103.5%. The detection limit was 0.05 microgram/g for each impurity.