Liquid Chromatographic Determination of Intermediates, Subsidiary Colors, and Two Reaction By-Products in FD&C Yellow No. 6: Reverse Phase Method

Abstract

A reverse phase liquid chromatographic (LC) method is presented for determining intermediates, subsidiary colors, and 2 reaction by-products in FD&C Yellow No. 6. Gradient elution from 0.02M ammonium acetate to 60% methanol in 0.02M ammonium acetate is performed on a C-8 column. Recoveries of the analytes from samples of FD&C Yellow No. 6 were as follows: 82 to 129% for the intermediate sulfanilic acid added at levels ranging from 0.04 to 0.2%; 85 to 107% for the intermediate Schaeffer's salt added at levels ranging from 0.03 to 0.3%; 91 to 107% for the reaction by-product 4,4'-(diazoamino)-dibenzenesulfonic acid added at levels ranging from 0.01 to 0.1%; 67 to 108% for the reaction by-product 6,6'-oxybis(2-naphthalenesulfonic acid) added at levels ranging from 0.1 to 1%; 88 to 100% for the subsidiary color 3-hydroxy-4-[(4-sulfophenyl)azo]-2,7-naphthaIenedisulfonic acid added at levels ranging from 0.7 to 5%; and 43 to 106% for the subsidiary color 6-hydroxy-5-(phenyIazo)-2-naphthalenesulfonic acid added at levels ranging from 0.1 to 1 %. To further demonstrate the capabilities of the method, results of multiple analyses of several FD&C Yellow No. 6 samples are presented, and results from corresponding analyses by an AOAC ion exchange LC method and by a thin layer chromatographic method are compared with results found with the new reverse phase LC method.

Determination of Seven Certified Color Additives in Food Products Using Liquid Chromatography

“…5, and FD&C Yellow No. 6 all consist of primary dye components as well as smaller amounts of subsidiary colors with higher or lower numbers of substituent groups. ,,− The subsidiary colors contribute to the total color additive content in food products but do not need to be determined in the products if the amounts of primary dye components in the color additive standards are known. The primary dye content was obtained by subtracting the subsidiary color content from the total dye content (Table ), and the primary dye content was used for quantitating the color additives in the products.…”

“…3) or gravimetric analysis (FD&C Red No. 3). − Subsidiary color content was determined by LC. − The content of primary dye components used for quantitation was obtained by subtracting the subsidiary color content from the total dye content. The results are reported in Table .…”