title: Understanding the bioavailability and sequestration of different metal cations in the presence of a biodegradable chelant S,S-EDDS in biological fluids and natural waters.
abstract: Ethylenediamine-N,N'-disuccinic acid is a biodegradable alternative to EDTA, therefore its use for the sequestration of Ca(2+), Sn(2+), Cu(2+), Zn(2+) and Fe(3+) is analyzed. New data on its binding ability towards these cations were obtained with potentiometric, voltammetric and calorimetric measurements at different ionic strengths and at T = 298.15 K. Real multi-component fluids, namely fresh water, urine, sea water, saliva and blood plasma were chosen as case studies to evaluate the sequestering ability of EDDS in comparison with EDTA. Speciation diagrams were drawn in selected conditions, considering all interactions among the "natural" components of the fluid and those studied in this work, EDDS and EDTA (cL = 1 mmol dm(-3)) as sequestering agents and the cited metal cations (cM ∼ 10(-5) mol dm(-3)). The comparison of the sequestering ability of EDDS and EDTA is done using pM and pL0.5. In blood plasma the plasma mobilizing index was adopted. It was found that EDDS is a good alternative to EDTA, which tends to bind Ca(2+) and Mg(2+) more than EDDS. In particular, EDTA cannot be used as a sequestrant for Sn(2+) when cCa > cEDTA. EDDS is more efficient than EDTA at pH < 8, particularly in urine, where carbonate is absent. In sea water, the sequestering ability of EDDS towards Fe(3+) is higher than that of EDTA. In blood plasma, the PMI of EDDS towards Cu(2+) is higher than that of EDTA. Thermodynamic information, in terms of ΔH and ΔS, for the protonation and metal complex formation reactions are reported.
authors.affiliation: Dipartimento di Scienze Chimiche, Biologiche, Farmaceutiche ed Ambientali, Università degli Studi di Messina, Viale Ferdinando Stagno d'Alcontres, 31, I-98166 Messina, Vill. S. Agata, Italy. Electronic address: cbretti@unime.it.
authors.forename: Clemente
authors.initials: C
authors.lastname: Bretti
authors.affiliation: Dipartimento di Scienze Chimiche, Biologiche, Farmaceutiche ed Ambientali, Università degli Studi di Messina, Viale Ferdinando Stagno d'Alcontres, 31, I-98166 Messina, Vill. S. Agata, Italy. Electronic address: rmcigala@unime.it.
authors.forename: Rosalia Maria
authors.initials: RM
authors.lastname: Cigala
authors.affiliation: Dipartimento di Scienze Chimiche, Biologiche, Farmaceutiche ed Ambientali, Università degli Studi di Messina, Viale Ferdinando Stagno d'Alcontres, 31, I-98166 Messina, Vill. S. Agata, Italy. Electronic address: cdestefano@unime.it.
authors.forename: Concetta
authors.initials: C
authors.lastname: De Stefano
authors.affiliation: Dipartimento di Scienze Chimiche, Biologiche, Farmaceutiche ed Ambientali, Università degli Studi di Messina, Viale Ferdinando Stagno d'Alcontres, 31, I-98166 Messina, Vill. S. Agata, Italy. Electronic address: glando@unime.it.
authors.forename: Gabriele
authors.initials: G
authors.lastname: Lando
authors.affiliation: Dipartimento di Scienze Chimiche, Biologiche, Farmaceutiche ed Ambientali, Università degli Studi di Messina, Viale Ferdinando Stagno d'Alcontres, 31, I-98166 Messina, Vill. S. Agata, Italy. Electronic address: ssammartano@unime.it.
authors.forename: Silvio
authors.initials: S
authors.lastname: Sammartano
mesh_terms: D001682:Biological Availability; D002412:Cations; D002623:Chemistry Techniques, Analytical; D004492:Edetic Acid / Q000737:chemistry; D004785:Environmental Pollutants / Q000032:analysis* / Q000097:blood / Q000652:urine; D005029:Ethylenediamines / Q000737:chemistry*; D006801:Humans; D019216:Metals, Heavy / Q000032:analysis* / Q000097:blood / Q000652:urine; D009994:Osmolar Concentration; D045483:Rivers / Q000737:chemistry*; D012463:Saliva / Q000737:chemistry*; D012623:Seawater / Q000737:chemistry*; D013386:Succinates / Q000737:chemistry*; D013816:Thermodynamics
chemical_list: C499100:(S,S)-ethylenediaminedisuccinate; D002412:Cations; D004785:Environmental Pollutants; D005029:Ethylenediamines; D019216:Metals, Heavy; D013386:Succinates; D004492:Edetic Acid
keywords: Case studies; Chelation; Heavy metals; Plasma mobilizing index; S,S-EDDS; Speciation