SOLVATOCHROMISM OF SOME FOOD AZO DYES

Abstract

In the current study the solvatochromic properties of such food azo dyes as tartrazine, sunset yellow FCF and carmoisine were described. It was shown that with an increase in the dielectric permittivity of the solvent, a bathochromic shift of the absorption band maxima of azo dyes is observed, which corresponds to the π → π* electronic transition. It has been established that the values of the molar absorptivities of the dominant acid-base form of azo dyes in organic solvents almost linearly (R≈0.90-0.92) increase with an increase in their dielectric permittivity. It is noted that there is a weak correlation (R = 0.70-0.80) between the position of the absorption maximum of the dye and the value of the Hansen parameter.