OP B10. ORGANIC COMPUNDS AS LIGANDS IN ION SELECTIVE ELECTRODES FOR HEAVY METALS MONITORINGASPECTS OF INTERACTION BETWEEN LIGANDS AND ANALYTES

I. Cretescu, D. Sibiescu, I. Rosca, D. Tutulea

“Gh.Asachi” Technical University of Iasi, Romania
Email: icre@ch.tuiasi.ro

Increasing amounts of heavy metals in natural environments, including in food products, created the necessity for monitoring of these toxic chemical elements in many different samples. The demand for cheap, easy to handle and versatile sensors for heavy metals has increased during the last decades. Apart from many traditional instrumental analytical methods, -e.g. integrated gas chromatography, and infrared, and mass spectrometry – the solvent polymeric membrane electrode has become a routine analytical tool, which has found applications in toxicological laboratories, biotechnology and food technology. In this paper, some aspects of interaction between different organic compounds as ligands incorporated in polymer matrix and some common heavy metals ions, as Cu2+; Ni2+; Co2+; Fe2+; Zn2+; Cd2+; Hg2+; Pb2+ were reported. The ligands tendency to coordinate these ions depends on the donor atom, and this decreases in the follow order: S> N> O> F. The formation and stability of the complex can not be limited only to the simple attraction between cations and ligands, but these have to take into consideration the electronics structure modification under the reciprocal action of electric fields or under influence of other electric fields. These heavy metals ions have the complexation tendency that depends on: the ionic radii and electric charge increasing and, decreasing with atomic number.