High pressure liquid chromatographic determination of uncombined intermediates in FD&C Red No. 2
Singh, M.
Journal - Association of Official Analytical Chemists 60(1): 173-175
1977
ISSN/ISBN: 0004-5756 PMID: 833093 Document Number: 116835
A high pressure liquid chromatographic (HPLC) method is presented for the separation and determination of uncombined intermediates in FD&C [Food Drug and Cosmetics] Red No. 2 (amaranth). Samples of FD&C Red No. 2 containing 0.1-0.3% naphthionic acid, 0.1-0.4% 2-naphthol-3,6-disulfonic acid, 0.3-1.0% 2-naphthol-6,8-disulfonic acid and 2-naphthol-3,6,8-trisulfonic acid were prepared and analyzed by HPLC. Recoveries ranged from 92-101%. Twenty samples of FD&C Red No. 2 were analyzed by the conventional column chromatographic method and the HPLC method. The HPLC method was superior, since it separated all the above intermediates from each other and from FD&C Red No. 2 in 1/4 the time required by the conventional column chromatographic method which did not separate the individual intermediates.