title: Interactions of diethylenetriaminepentaacetic acid (dtpa) and triethylenetetraaminehexaacetic acid (ttha) with major components of natural waters.
abstract: The binding ability of diethylene triamine pentaacetate (dtpa(5-)) and triethylene tetraamine hexaacetate (ttha(6-)) ligands towards major components, H(+), Na(+), Mg(2+) and Ca(2+), of natural waters was studied in both single and mixed ionic media at different ionic strengths and at T=25 degrees C. Some measurements, performed in Mg(2+)-Ca(2+) mixtures, allowed us to find the formation of new mixed species MgCa(dtpa), MgCa(ttha) and MgCaH(ttha), here reported for the first time. All the complexes formed in the various systems were characterized in terms of both stoichiometry and stability, and an attempt was made to find general rules for the stability of mixed metal complexes in comparison with that of simple species. To obtain quantitative information on the complexing ability of dtpa and ttha in seawater, measurements have been carried out in artificial seawater ionic medium (Na(+), K(+), Ca(2+), Mg(2+), Cl(-) and SO(4)(2-)). Calculations, performed by considering the salt mixture as single salt BA, allowed us to find some quite stable B(i)H(j)L species. Under the natural seawater conditions [S(salinity)=35], we found for the most important species logbeta( B(dtpa))=9.64 and. Literature data comparison is also reported.
authors.affiliation: Dipartimento di Chimica Inorganica, Chimica Analitica e Chimica-Fisica dell'Università, Salita Sperone 31, 98166, Vill. S. Agata, Messina, Italy.
authors.forename: Concetta
authors.initials: C
authors.lastname: De Stefano
authors.forename: Antonio
authors.initials: A
authors.lastname: Gianguzza
authors.forename: Daniela
authors.initials: D
authors.lastname: Piazzese
authors.forename: Silvio
authors.initials: S
authors.lastname: Sammartano
mesh_terms: D002614:Chelating Agents / Q000737:chemistry*; D002712:Chlorides / Q000737:chemistry; D004492:Edetic Acid / Q000031:analogs & derivatives* / Q000737:chemistry*; D007477:Ions / Q000737:chemistry; D008024:Ligands; D008670:Metals / Q000737:chemistry; D009942:Organometallic Compounds / Q000737:chemistry; D004369:Pentetic Acid / Q000737:chemistry*; D012623:Seawater / Q000737:chemistry*; D013431:Sulfates / Q000737:chemistry
chemical_list: D002614:Chelating Agents; D002712:Chlorides; D007477:Ions; D008024:Ligands; D008670:Metals; D009942:Organometallic Compounds; D013431:Sulfates; D004369:Pentetic Acid; C026059:triethylenetetraminehexaacetic acid; D004492:Edetic Acid