Raw materials, intermediates and subsidiary colors in Food Yellow No. 5 (Sunset Yellow FCF) were determined by HPLC as part of the approach to development of international harmonized specifications for food additives. Thirty nine samples of commercial Sunset Yellow FCF in Japan and U.S.A. were examined, with the following results for ingredients: Sub A, 0.008〜0.976%; Sub B, 0.003〜0.737%; RS-SA, N.D.〜4.645%; GS-SA, N.D.〜0.570%; mixture of SS-AN and 2N-SA, 0.015〜0.496%; SA, 0.004〜0.057%; SS, g/g for each impurity. Table 1 explains the distinction between type I, type II, type III and type IV. Type I was free from subsidiary colors. Type II contained sub A. While type III contained sub B. Type IV contained relatively large amounts of subsidiary colors, especially RS-SA being observed as impurities at levels of 3〜5%.
