The interaction between eriochrome black T and Li , Na , K ,Mg and Ca
ions in acetone and dimethylsulphoxide solutions has been investigated
spectrophotometrically. The formation constants of the resulting 1 : 1 complexes were
determined and found to decrease in the order Mg >Ca >Li >K >Na in both
solvents used. There is an inverse relationship between the stabilities of the
complexes and the solvating ability of the solvents