Thermodynamic Study on the Interaction between Fe2+(aq) ion and LAlanine

Document Type : Research Paper




Using UV-VIS spectrophotometric method, the formation constant for interaction of Fe2+(aq) ion with L-Alanine
was experimentally studied at pH = 4.1 ± 0.01 (50mM of potassium hydrogen phthalate buffer), ionic strength
of 0.1M potassium nitrate and at 5 different temperatures 15,20, 25,30 and 35 T. The optical absorption spectra
of mixtures containing considered cation and L-Alanine were analyzed by using SQUAD software, in order to
obtain the formation constant and the stoichiometry of respect complex. The best fitting of our results showed
the 1:2 complex respect to the studied system (Fe2+00 + L-Alanine) is formed. Regarding the value of formation
constants at different temperatures and using Van' t Hoff equation, it is possible to calculate the respective
thermodynamic functions of formation such as AG', An' , AS', ... of the studied complex.