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), Quinolin e 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, c alled ''ratio spectrum zero crossing derivative'', is based on the sim ultaneous use of the first derivative of ratio spectra and measurement s at ''zero-crossing'' wavelengths. The two described procedures do no t require any separation step. The calibrations graphs are linear up t o 20 mug/mL for Tartrazine, 40 mug/mL for Sunset Yellow and 24 mug/mL for Quinoline Yellow in both methods. The methods are applied to deter mine these compounds in three food commercial products.