title: Determination of unsulfonated aromatic amines in FD&C Yellow No. 6 by the diazotization and coupling procedure followed by reversed-phase high-performance liquid chromatography.
abstract: Data are presented for the determination of parts-per-billion (10(9)) levels of aniline, benzidine, 4-aminobiphenyl (4-ABP) and 4-aminoazobenzene in the regulated color additive FD&C Yellow No. 6. The determination involves chloroform extraction of the amines from the color additive, followed by diazotization and coupling with the disodium salt of 3-hydroxy-2,7-naphthalenedisulfonic acid (R-salt). The coupling products are then analyzed by reversed-phase high-performance liquid chromatography. An interference discovered during the determination of 4-ABP required the use of 4,5-dihydro-5-oxo-1-(4-sulfophenyl)-1H-pyrazole-3-carboxylic acid (pyrazolone-T) as an alternative coupling agent. The identity of each coupling product is confirmed by obtaining a UV-visible spectrum of the eluting solute. The liquid chromatograph is calibrated in the presence of the color additive by using the external standard method.
mesh_terms: D000588:Amines / Q000032:analysis; D001391:Azo Compounds / Q000032:analysis*; D055598:Chemical Phenomena; D002621:Chemistry; D002851:Chromatography, High Pressure Liquid; D003979:Diazonium Compounds / Q000032:analysis; D013056:Spectrophotometry, Ultraviolet
chemical_list: D000588:Amines; D001391:Azo Compounds; D003979:Diazonium Compounds; C005842:6-hydroxy-5-((p- sulfophenyl)azo)-2-naphthalenesulfonic acid disodium salt