Separation and Determination of FD&C Red No. 4 and FD&C Red No. 40 in Maraschino Cherries by Column Chromatography

Abstract

Abstract FD&C Red No. 4 and FD&C Red No. 40 are extracted from a sample-Celite mixture in a chromatographic column by elution with a 5% solution of Amberlite LA-2 liquid anion exchange resin in n-butanol. The colors are extracted from the resin with dilute ammonia and then extracted into n-butanol. After evaporation to dryness, the colors are separated by Celite chromatography, using pH 1.5 HCl buffer as immobile phase. Red No. 4 is eluted with n-butanol-CCl4 (1+1) and Red No. 40 is eluted with a 5% solution of Amberlite LA-2 resin in hexane. The compounds are measured spectrophotometrically. Results on a commercial sample (5 trials) ranged from 74 to 76 ppm Red No. 4 and 72 to 81 ppm Red No. 40. Spike recoveries at various levels averaged 98% for FD&C Red No. 4 and 95% for FD&C Red No. 40.