Chemical speciation of L-glutamic acid complexes of some toxic metal ions in DMSO-water mixtures

Chemical speciation of L-glutamic acid complexes of some toxic metal ions has been investigated pH-metrically in DMSO-water mixtures (0-60% v/v) at 303 K and ionic strength of 0.16 mol L-1. The predominant species detected for Pb-II and Cd-II are ML2H4, ML2H3, ML2H2, ML2 and ML and for Hg-II are ML2H4, ML2H3, ML2H2 and ML. The trends in variation of stability constants of the complexes with dielectric constant of the medium are attributed to the electrostatic and non-electrostatic forces.