Liquid chromatographic determination of 2,4-dinitroaniline and 2-naphthol in D&C Orange No. 17.
A method is described for the determination of the intermediates in D&C Orange No. 17 by reverse phase liquid chromatography. The pigment is dissolved in boiling dioxane and then precipitated. The filtrate is chromatographed by isocratic elution, which is followed by a wash and equilibration. Peak area calibrations were linear. At the provisional specification levels, 99% prediction limits were 0.200 +/- 0.0012% 2,4-dinitroaniline (2,4-DNA) and 0.200 +/- 0.006% 2-naphthol. The limits of determination were 0.0023% for 2,4-DNA and 0.013% for 2-naphthol at the 99.5% confidence level. Recoveries were 98-100% for 2,4-DNA added at the 0.005-2% level, and 93-103% for 2-naphthol added at the 0.025-2% level. A survey of certified D&C Orange No. 17 samples showed that the lots contained higher levels of the intermediates than were determined previously by a cellulose column method, in which the pigment is not dissolved.
D000814:Aniline Compounds / Q000032:analysis*; D001391:Azo Compounds / Q000032:analysis*; D002853:Chromatography, Liquid; D004396:Coloring Agents / Q000032:analysis*; D009284:Naphthols / Q000032:analysis*
D000814:Aniline Compounds; D001391:Azo Compounds; D004396:Coloring Agents; D009284:Naphthols; C010934:2,4-dinitroaniline; C045949:1-((2,4-dinitrophenyl)azo)-2-naphthalenol; C028405:2-naphthol