A sensitive, reproducible method that uses an Extrelut QE column and liquid chromatography (LC) in the reverse phase mode is described for the determination of 2-(2-quinolinyl)-1H-indene-1,3-[2H]-dione and other organic-soluble matter found in D&C Yellow No. 10. With this method the organic-soluble matter is extracted from D&C Yellow No. 10 on an Extrelut QE column, and the extract is concentrated and analyzed by LC. Recoveries averaged 104% for 2-(2-quinolinyl)-1H-indene-1,3-[2H]-dione added to purified D&C Yellow No. 10 at levels ranging from 0.50 to 5.96 ppm.
