D&C Red No. 34 (R34, thecalcium salt of3-hydroxy-4-[(1-sulfo-2-naphthalenyl)azo]-2-naphthalenecarboxylic acid) is amonoazo color additive listed in the U.S. Code of Regulations (CFR) for use inexternally applied drugs and cosmetics. R34 must be batch-certified by FDA toensure compliance with requirements in 21 CFR74.1334, including a specification for subsidiary colors of 4 percent. Thesecolored impurities are positional isomers of R34 or have lower numbers ofsubstituent groups. We have developed a rapid and reliable reversed-phaseliquid chromatography (LC) method for the determination of the subsidiarycolors. In this poster, we describe six synthesized subsidiary colors, aseventh recrystallized subsidiary color, and their characterization byelemental analysis, LC, and multidimensional nuclear magnetic resonancespectroscopy. We also present LC analyses of several R34 samples using thecharacterized subsidiary colors as standards.

Determination of subsidiary colors in D&C Red No.
34 by reversed-phase liquid chromatography

239th National Meeting (2010)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.

Determination of subsidiary colors in D&C Red No. 34 by reversed-phase liquid chromatography