SIMULTANEOUS DETERMINATION OF AMARANTH AND SUNSET YELLOW BY RATIO DERIVATIVE VOLTAMMETRY

A ratio derivative voltammetric method for resolving overlapping volta mmograms without a pre-separation is described. The method is based on the use of the first derivative of ratios of the voltammograms of bin ary mixtures. The voltammogram of the mixture is obtained and the ampl itudes of the current at appropriate potentials are divided by the cor responding amplitudes in the voltammogram of a standard solution of on e of the components, and the first derivative of the ratio voltammogra m is obtained. The concentration of the other component is then determ ined from a calibration graph. The method has been successfully applie d for resolving binary mixtures of Amaranth and Sunset Yellow, which h ave overlapped adsorptive voltammograms in pH 6.0 McIlvane buffers.