SIMULTANEOUS DETERMINATION OF SUNSET YELLOW FCF AND SUDAN I BY SOLID-PHASE SPECTROPHOTOMETRY

A new, sensitive and simple spectrophotometric method for the simultan eous determination of Sunset Yellow FCF and Sudan I in mixtures is pro posed. The method is based on the isolation of Sunset Yellow FCF on Se phadex diethylaminoethyl (DEAE) A-25 gel (pH 5.0) and the isolation of the Sudan I on C-18 silica gel (pH 5.0) measuring, directly, their ab sorbances in the solid phase at lambda = 487 nm in both cases. The con centration ranges applicable were between 15 and 500 ng ml(-1) for Sun set Yellow FCF and between 20 and 200 ng ml(-1) for Sudan I with detec tion limits of 3.5 and 4.4 ng ml(-1), respectively. The method was app lied to the determination of mixtures of both compounds in synthetic c olourings used as additives in food, drugs and cosmetic products.