Simultaneous spectrophotometric determination of ternary mixtures of Tartrazine, Sunset Yellow, and Ponceau 4R by H-point standard addition method

A simple UV spectrophotometric method has been developed for resolving ternary mixture of food colorants, Tartrazine, Sunset Yellow and Ponceau 4R, which are species with highly overlapped spectra, by using H-point standard addition method (HPSAM). In this method, the concentration of one colorant was calculated from overlapping spectra at two appropriate wavelengths, where the other two colorants were selected as interferents present the equal absorbance relationship. These wavelength pairs are generally easily found, and can be selected to give the most precise analytical results. This method was satisfactorily applied to determination of colorants of Tartrazine, Sunset Yellow and Ponceau 4R in synthetic ternary mixtures and several commercial products.