Nonsulfonated aromatic amines

Free and bound nonsulfonated aromatic amines were determined in allura red by ion-pair chromatography after reduction with dithionite, diazotization with sodium nitrite, and coupling with R-salt (202). 

Sunset yellow was separated from its subsidiary dye l-p-sulfophenylazo-2-naphthol-3,6-disulfonic acid trisodium salt (195) and from its intermediates sulfanilic acid and Schaeffer s salt (194) by means of ion-pair HPLC. Ion-pair chromatography has also been used to determine free and bound nonsulfonated aromatic amines in sunset yellow after reduction with dithionite, diazotization with sodium nitrite, and coupling with R-salt (202). 

Carcinogenity and toxicity must be checked therefore not only for dyes but also for the impurities therein contained and their degradation products. A number of these nonsulfonated aromatic amines (NAAS) have been found to be carcinogenic to humans and animals. 

Allied with the chromatography of imidazoles have been methods of estimation of the compounds, particularly those of biological importance, either on the chromatograms or after elution. Most workers have used diazotized aromatic amines as colorimetric reagents,53,277-285 particularly nonsulfonated diazotized aniline derivatives.281-285 Mosebach et aZ.286 initially hydrolyzed. -substituted imidazoles with 10 A hydrochloric acid before separating the compounds by ion-exchange and paper chromatographic techniques prior to estimation. A number of other methods exist for the colori-... 

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