Structural Determination of Unknown Subsidiary Colors in Food Yellow No. 5(Sunset Yellow FCF)

Abstract

Major unknown subsidiary colors A (Sub A) and B (Sub B) in commercial Sunset Yellow FCF (Food Yellow No. 5 in Japan) have been isolated by preparative HPLC. Spectroscopic analyses of Sub A and Sub B revealed that their structures are trisodium salt of 6-hydroxy-7-(4-sulfophenyl)-5-(4-sulfophenylazo)-2-naphthalenesulfonic acid, and disodium salt of 3-hydroxy-4-(4-sulfophenylazo)-2-naphtalenesulfonic acid, respectively.