A Rapid Spectrophotometric Method to Resolve a Binary Mixture of Food Colorants (Riboflavine and Sunset Yellow)


Abstract: A very simple and rapid spectrophotometric method using measurements at zero-crossing wavelength is described for resolving binary mixtures of riboflavine (E-101) and sunset yellow (E-110) in a powder drink. The assay procedure for E-110 and E-101 involves the extraction of the colorants from the powder drink with pH 4.5 acetate buffer, filtration, appropriate dilution, and measurement of the first derivative absorbance values (denoted as ^1D). Calibration graphs are linear up to 25.0 \mu g.mL^{-1} for E-101 and 40.0 \mu g.mL^{-1} for E-110. The sensitivity and reproducibility of the method were determined by using the synthetic mixtures in different ratios prepared by us, and the proposed method was applied to a commercially available powder drink. The relative standard deviations obtained are 1.39% and 1.15% and the average percentage recoveries are 101.0% and 102.8% for E-101 and E-110, respectively.

Keywords: Derivative spectrophotometry, simultaneous determination, zero-crossing measurements, sunset yellow, riboflavine, colorants, food analysis

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