Spectrophotometric study of the complexation equilibria of yttrium(III) with quinizarin green

The complexation equilibria of yttrium(III) with quinizarin green [1,4-bis(4′-methylanilino)anthraquinone] were studied spectrophotometrically in the presence of 40% dimethylformamide at 20 °C and an ionic strength of 0.1 M(NaClO4). The composition, molar absorptivities, equilibrium constants and stability constants of the complexes formed were determined using graphical analysis of the absorbance curves within the pH range studied. The optimum conditions for the spectrophotometric determination of Y(III) with this reagent were established.