Simultaneous determination of quinoline yellow and brilliant blue FCF in cosmetics by solid-phase spectrophotometry

A method for the simultaneous determination of quinoline yellow (QY) and brilliant blue FCF (BB) in mixtures by solid-phase spectrophotometry has been developed. Both colorants were isolated in Sephadex DEAE A-25 gel showing maximum absorbances at 632 nm and 415 nm for BB and QY respectively. The applicable concentration ranges were between 25.0 and 500.0 mug 1(-1) for BB and between 50.0 and 750.0 mug 1(-1) for QY. The detection limits were 6.1 and 13.4 mug (-1) for BB and QY respectively. Application of the method to real samples (colognes, after shave lotions and shampoo gels) involves a previous extraction process of the colorants before their isolation on the gel.