Resolution of Ternary Mixture of Tartrazine, Quinoline Yellow and Sunset Yellow by Derivative Spectrophotometry and Ratio Spectra Derivative

Two methods for determining the colorants Tartrazine (E-102), Quinoline Yellow (E-104) and Sunset Yellow (E-110) in mixtures are described. As first method was used the second derivative spectrophotometry with measurement in the “zero-crossing” wavelengths. The second method, called “ratio spectrum zero crossing derivative”, is based on the simultaneous use of the first derivative of ratio spectra and measurements at “zero-crossing” wavelengths. The two described procedures do not require any separation step. The calibrations graphs are linear up to 20 μg/mL for Tartrazine, 40 μg/mL for Sunset Yellow and 24 μg/mL for Quinoline Yellow in both methods. The methods are applied to determine these compounds in three food commercial products.