Author : D. Fahad, Fahad
journal of kerbala university,
Volume 11, Issue 2, Pages 43-57
Arsenic is one of the toxic heavy metal when presented in a high level over it allowable limit. To detoxify this heavy metal a chelators were used as in a chelation therapy. This work studies the complexation of some chelators (EDTA, penicillamine, genistein and qurecetin) with As III ion. A spectrophotometric techniques were applied in water and water-ethanol mixture as a solvent, at four different temperature. A shift in it max and decrease in absorbance indicating the complex formation. The stoichiometry of these complexes were determined by a method of the continuous variation (Job's) method, it was found that As-EDTA were (2:1), As-gensitein and As-quercetin (1:1), and As-penicillamine (1:2). These chelator's have a high tendency to complex with As III ion which were reflected by its high values of their equilibrium constants. Thermodynamic parameters indicate a spontaneous interaction (negative free energy change Go), and the enthalpy changr for As-gensitein complex were positive and the other three complexes have negative Ho which depends on type of the interaction and the structures of the complexes. The kinetic calculations shows a second order interaction.