Automated High Pressure Liquid Chromatographic Determination of Uncombined Intermediates in FD&C Red No. 40 and FD&C Yellow No. 6

Abstract

Abstract An automated high pressure liquid chromatographic (HPLC) method is presented for the isolation and determination of uncombined intermediates in FD&C Red No. 40 (Allura Red AC) and FD&C Yellow No. 6 (CI No. 15985). Samples of FD&C Red No. 40 containing 0.1-0.4% cresidine sulfonic acid (4-amino-5-methoxy-2-methyl benzene sulfonic acid), 0.1-0.3% Schaeffer's salt (6-hydroxy-2-naphthalene sulfonic acid), 0.02- 0.08% 4,4'- (diazoamino) -bis (5-methoxy-2-methyl benzene sulfonic acid), and 0.1-1.0% 6,6'-oxybis (2-naphthalene sulfonic acid) were prepared and analyzed by this method. Recoveries ranged between 95 and 101%. Sixty samples of FD&C Red No. 40 were analyzed by the automated HPLC method. Results showed good agreement with those of the manual HPLC method. Samples of FD&C Yellow No. 6 containing 0.1-0.4% sulfanilic acid (4-aminobenzene sulfanilic acid), 0.1-0.3% Schaeffer's salt, 0.02-0.08% 4,4'-(diazoamino)-dibenzene sulfonic acid, and 0.2-1.0% 6,6'-oxybis (2-naphthalene sulfonic acid) were prepared and analyzed by this method. Recoveries ranged between 96 and 101%. Forty samples of FD&C Yellow No. 6 were analyzed by the automated HPLC method. Results showed good agreement with those of the manual HPLC method.