Pedro Luis López-de-Alba, Luis Ivan Michelini-Rodriguez, Katarzyna Wróbel and Judith Amador-Hernández
A simple extraction–spectrophotometric method for the determination of tartrazine (Tz) and Sunset Yellow (SY) in mixtures, based on the extraction of the ion pairs formed between the dyes and trioctylmethylammonium chloride (Adogen-464) into toluene, is described. With the proposed method, calibration graphs are linear up to 3.0 µg ml–1 for Tz and 3.6 µg ml–1 for SY. The bivariate calibration method was applied to the resolution of binary mixtures of the dyes and the results were compared with those given by first-derivative spectrophotometry. The methods were applied to the determination of both compounds in commercially available food products.