Adsorption of Sunset Yellow FCF food dye from aqueous solutions and its determination by diffuse reflectance spectroscopy

The adsorption of Sunset Yellow FCF food dye (Orange Yellow S, E-110) from aqueous solutions on silica adsorbents modified by alkyl groups and on γ-Al2O3 is studied. The adsorption attains a maximum in the range 1 M HCl-pH 1 on Diasorb-130-C16 (79–87%), 0.5 M HCl-pH 6.8 on Diasorb-130-C16 and Diasorb-100-C8 in the presence of trimethylammonium bromide (92–98%), and pH 1–5.6 on γ-Al2O3 (72–87%). Calibration graphs of the dependence of the Kubelka-Munk function F on the dye concentration in aqueous solutions are built. The possibility of the preconcentration of trace amounts of the dye from large volumes of solutions is shown. A method of dye determination is proposed based on its separation by adsorption followed by determination by diffuse reflectance spectroscopy directly in the adsorbent phase and used in the analysis of the O! Orange drink. The accuracy of the determination is verified by comparison with the results obtained by the GOST P 52470-2005 procedure.