High Pressure Liquid Chromatographic Determination of Uncombined Intermediates and Subsidiary Colors in Orange B

Abstract

Abstract A high pressure liquid chromatographic (HPLC) method has been developed for isolating and determining uncombined intermediates and subsidiary colors in Orange B. Samples of Orange B containing 0.1–0.3% naphthionic acid, 0.05–0.2 % phenylhydrazine-p-sulfonic acid, 0.2–0.8% pyrazolone-T and ethyl ester of pyrazolone-T, 0.2–1.0% 3-[(4-sulfo-l-naphthalenyl)-azo]-4-amino-l-naphthalenesulfonic acid, and 0.1–6.0% Orange K were prepared and analyzed by using this method. Recoveries ranged from 95 to 103%, except for the phenylhydrazine-p-sulfonic acid which ranged from 95 to 140%. Ten samples of Orange B were analyzed by conventional column and thin layer chromatographic methods as well as by the HPLC method. Good agreement was obtained for naphthionic acid, Orange K, and naphthionic acid plus the naphthionic acid subsidiary.