Potentiometric study of binary complexe of amino acid glycine with metal ion Zn2+ in aqueous solution

The protonation and stability constant of complexation between glycine amino acid with zn2+ ion in aqueous solution were studied potentiometrically. all of titration procedures were carried out at 25±0.1 °c and ionic strength (μ) of 0.1 m supported by nano3. the protonation and overall stability constants (logβ's) of species has been evaluated by computer refinement of ph-volume data using best computer program. several model are tested and based on the lowest σfit,the best one is accepted. the distribution diagram of all species in absence and presence of metal ion as function of ph with sp and spe programs was given.