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 tern ary mixture of food colorants, Tartrazine, Sunset Yellow and Ponceau 4R, wh ich are species with highly overlapped spectra, by using H-point standard a ddition method (HPSAM). In this method, the concentration of one colorant w as calculated from overlapping spectra at two appropriate wavelengths, wher e the other two colorants were selected as interferents present the equal a bsorbance relationship. These wavelength pairs are generally easily found, and can be selected to give the most precise analytical results. This metho d was satisfactorily applied to determination of colorants of Tartrazine, S unset Yellow and Ponceau 4R in synthetic ternary mixtures and several comme rcial products.