Use of second-order calibration and second-order data allows to determination the interest analyte in the presence of uncalibrated sample constituents, a property known as the second-order advantage. To determination synthetic food colors in the presence of other dyes compound with similar structures and overlay spectrums, the second order calibration algorithms based on the rank annihilation factor analysis (RAFA) were used[1]. In this method, pH in the range of 1-12 was changed gradually and the absorption spectra of standard dye and real samples were recorded in the range of 200-700 nanometer. Thus, the concentration of sunset yellow and erythrosine in black system[2,3] could be determined from the spectra matrices using second order calibration algorithms. This method is simple, convenient and dependable. The method has been used successfully to determine sunset yellow and erythrosine in simulated saffron sample with satisfactory results with 6% and 4% relative errors, respectively

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