Spectrophotometric resolution of ternary mixtures of amaranth, Carmoisine and Ponceau 4R by the derivative ratio spectrum-zero crossing method

Abstract

A method for the simultaneous determination of Amaranth, Ponceau 4R and Carmoisine dyes in ternary mixtures is proposed, with no separation step; this is based on the simultaneous use of the first derivative of ratio spectra and measurements at zero-crossing wavelengths. The calibration graphs are linear up to 32 mg/L of Amaranth, Carmoisine and Ponceau 4R. The mean recovery is 102.1, 95.3 and 102.6 %, respectively. The method was applied to several food products.