STUDY OF STOICHIOMETRY an‎d STABILITY OF SOME Fe(III)-AMINO ACID COMPLEXES

The complexation of ferric with three amino acids (Glycine, Glutamic acid and Aspartic acid) was studied spectrophotometrically and potentiometrically at pH 5.0 and in aqueous medium. The stoichiometry was calculated spectrophotometrically using mole ratio method and is found to be ML3 for Fe(III)-Glycine and ML2 for Fe(III)-Glutamate and Aspartate complex. The stabilities of these complexes were calculated spectrophotometrically and potentiometrically. The experimental results of potentiometric titrations were treated by well known computer program BEST. The values were further refined till least sigma fit i.e.0.03. The complexes were not formed under normal conditions. Each complex was studied at more than one wavelength and no kmax was obtained because Fe(III) solution and the complexes absorb in similar wavelength region. The formation constants of all these complexes are not very high shows weak complexation of Fe(III) with these amino acids.