Determination of the lower sulfonated subsidiary colors in FD&C Yellow No. 6 by reversed-phase high-performance...

Data are presented for the determination of 5-(phenylazo)-6-hydroxynaphthalene-2-sulfonic acid (ANSC) and 4-[(2-hydroxynaphthalene-1-yl)azo]benzenesulfonic acid (BNSC) in FD&C Yellow No. 6 by reversed-phase high-performance liquid chromatography (RP-HPLC). The method employs gradient elution with a water-tetrahydrofuran solvent system buffered with ammonium acetate and quantitation in the UV (254 nm) and visible (490 nm) regions. The external calibration method was used with twelve data points for each analyte. Each analysis was performed in duplicate. In analyses of commercial FD&C Yellow No. 6, ANSC was found at levels ranging from none to 0.52, and BNSC was found at levels ranging from none to 0.73%. The identities of the analytes were confirmed by using a rapid-scan diodearray spectrophotometer to obtain the electronic absorption spectra during RP-HPLC analysis.