title: Application of the new electroanalytical technique AGNES for the determination of free Zn concentration in river water.
abstract: Absence of gradients and Nernstian equilibrium stripping (AGNES) is a recently developed electroanalytical technique specifically designed for the direct determination of free concentrations of metal ions. AGNES is applied here to the determination of free Zn concentration in a river water sample. The method has been validated with synthetic solutions of low ionic strengths containing Zn and 2,6-pyridinedicarboxylic acid and then applied to synthetic river waters and to a natural sample collected from Besòs River in Montcada i Reixac (Catalonia, North-Eastern Spain). In the river sample, an average free Zn concentration of 12.8(4) nM was obtained, while the total dissolved Zn concentration was 0.51(8) microM. To control and maintain pH and pCO(2) constant during AGNES measurements, a novel device for N(2)/CO(2) mixed purging has been developed.
authors.affiliation: Dipartimento di Chimica Generale, Università di Pavia, via Taramelli 12, 27100, Pavia, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Zavarise
authors.affiliation: Departament de Química, Universitat de Lleida, Rovira Roure 191, 25198, Lleida, Spain.
authors.forename: Encarnació
authors.initials: E
authors.lastname: Companys
authors.affiliation: Departament de Química, Universitat de Lleida, Rovira Roure 191, 25198, Lleida, Spain. galceran@quimica.udl.es.
authors.forename: Josep
authors.initials: J
authors.lastname: Galceran
authors.affiliation: Dipartimento di Chimica Generale, Università di Pavia, via Taramelli 12, 27100, Pavia, Italy.
authors.forename: Giancarla
authors.initials: G
authors.lastname: Alberti
authors.affiliation: Dipartimento di Chimica Generale, Università di Pavia, via Taramelli 12, 27100, Pavia, Italy.
authors.forename: Antonella
authors.initials: A
authors.lastname: Profumo