Solvent influence on absorption spectra of food azo dyes

Abstract

The solvent influence on absorption spectra of food azo dyes was examined by the method of Linear Solvation Energy Relationships (LSER). For this purpose, six azo dyes were used: tartrazine (E 102), ponceau 4R (E 124), azorubin (E 122), brilliant black (E 151), amaranth (E 123) and gelb orange S (E 110). Absorption spectra of dissolved azo dye have been recorded in the wavelength range of visible radiation, or from 380 to 760 nm, in eight solvent of different polarity. The choice of the solvent was limited due to the high polarity of the azo dye molecules themselves. The effect of solvent dipolarity/polarizability and solvent/solute hydrogen bonding interaction are analysed by means of the linear solvation energy relationship (LSER) concept proposed by Kamlet and Taft. The linear correlation of the absorption maxima with parameters of Kamlet-Taft solvatochrome equation yielded satisfactory results.

Uticaj polarnosti rastvarača na apsorpcione spektre prehrambenih azo boja ispitivan je metodom linearne korelacije energije solvatacije (LSER). U ovu svrhu korišćeno je šest prehrambenih azo boja i to: tartrazin (E 102), ponceau 4R (E 124), azorubin (E 122), brilijant crna (E 151), amarant (E 123) i gelb oranž S (E 110). Apsorpcioni spektri rastvorenih azo boja određeni su u talasnom opsegu vidljivog zračenja, odnosno u opsegu od 380 do 760 nm, u osam rastvarača različite polarnosti. Polarnost samih boja je uticala na izbor malog broja polarnih rastvarača. Spektre ispitivanih azo boja karakteriše jedan apsorpcioni maksimum. Efekat polarnosti rastvarača i efakat vodoničnog vezivanja rastvarač-rastvorena supstanca ispitivan je primenom KamletTaftove solvatohromne jednačine. Linearna korelacija apsorbcionih maksimuma sa parametrima Kamlet-Taftove solvatohromne jednačine dala je zadovoljavajuće rezultate.