title: Liquid chromatographic determination of intermediates in D&C Yellow No. 7 and D&C Yellow No. 8.
abstract: A sensitive, reproducible method that uses liquid chromatography in the reverse phase mode has been developed for the determination of phthalic acid, resorcinol, and 2-(2',4'-dihydroxybenzoyl)benzoic acid in D&C Yellow No. 7 and D&C Yellow No. 8. The method uses a 10 micron, C-8 column, a 1% acetic acid-methanol gradient, and UV absorption detection at 280 nm. Average recoveries of phthalic acid, resorcinol, and 2-(2',4'-dihydroxybenzoyl)benzoic acid were 100, 98, and 102%, respectively, from fluorescein standard (certifiable as D&C Yellow No. 7) spike with each compound at levels ranging from 0.13 to 1.3%.
mesh_terms: D002853:Chromatography, Liquid; D004396:Coloring Agents / Q000032:analysis*; D019793:Fluorescein; D005452:Fluoresceins / Q000032:analysis*; D007202:Indicators and Reagents
chemical_list: D004396:Coloring Agents; D005452:Fluoresceins; D007202:Indicators and Reagents; D019793:Fluorescein