Electrochemical investigation of complexation
and speciation of zinc with 1,10-Phenanthroline (phen) in
aqueous solution have been performed by an
electrochemical technique, DPASV, using Mercury Film
Coated Glassy Carbon Electrode (MFGCE). The work was
carried out at constant pH and ionic strength.The overall
formation constants of different complexes of zinc with
phen were measured by applying Leden, DeFord and Hume
model.It was found that three (1:1, 1:2 & 1:3; metal:ligand)
complexes were formed with phen under the experimental
conditions used in this work.The overall formation constant
of complexes, Zn(phen)n which can be defined as Zn(Phen)n =
[Zn(Phen)n]/[Zn2+][Phen]n
[where, ‘Phen’ is the complexing
ligand and ‘n’ is an integer]. The values of the formation
constants were found to be 106.66, 1012.30 and 1017.44 for
Zn(Phen), Zn(Phen)2 and Zn(Phen)3, respectively (for
simplicity charges of the complexes were omitted).Finally it is concluded that electrochemical
technique, specially DPASV is a simple and powerful tool to
investigate the metal organic interaction in aqueous
solution. Thin mercury film coated glassy carbon electrode
acts as an ultra-microelectrode which is more sensitive than
any other hanging mercury or dropping mercury electrode.
Keywords : DPASV, Complexation, Speciation, Mercury Film Coated Glassy Carbon Electrode.