Application of Counter Alternative Current Chromatography to Purification of Food Mono-Azo Dyes

Abstract

Counter alternative current chromatography was applied to the purification of food mono-azo dyes. Commercially available reagent-grade Food Red No. 2, Red No. 102 and Yellow No. 5 allowed the presence of ca. 99.0, 98.7 and 96.1% of the main dye, respectively, according to high performance liquid chromatography. The phase system used for purification comprised 2-butanol : water (1:1 by volume). Purified Red No. 2, Red No. 102 and Yellow No. 5 were obtained in proportions of 99.7 (ca. 110mg), 99.5 (ca. 280mg) and 99.3% (ca. 290mg) from 1g (Red No. 2, Red No. 102) and 2.5g (Yellow No. 5) of the commercial dyes.