Determination of Zn2+ concentration with AGNES using different strategies to reduce the deposition time
Codina Montull, Glòria
MetadataShow full item record
Absence of gradient and Nernstian equilibrium stripping (AGNES) senses the free ion concentration of Zn(II) in solutions containing different ligands, being unaffected by the lack of reversibility of the Zn2+/Zn0 couple under the conditions assayed. In the presence of oxalate, the determination of [Zn2+] agrees with the stability and solubility constants of this sparingly soluble salt, once the precipitation kinetics are taken into account. Different strategies have been analysed and implemented in order to reduce the preconcentration time with the standard electrode of the polarographic stand (smallest drop radius around 0.141 mm): (i) using a lower preconcentration factor when there is no need of enhanced limit of detection; (ii) splitting the deposition stage into two, with a first potential step under diffusion limited conditions; (iii) the analysis of the chronoamperometric response in the deposition stage allows its duration to be adjusted, especially if non-inert complexes contribute to the arriving flux of metal to the mercury electrode. The two-potential-steps strategy is assessed as the most suitable in a general case.
Is part ofJournal of Electroanalytical Chemistry, 2005, vol. 576, num. 1, p. 21-32
European research projects
Showing items related by title, author, creator and subject.
Full-wave analysis of stripping chronopotentiograms at scanned deposition potential (SSCP) as a tool for heavy metal speciation: Theoretical development and application to Cd(II)-phthalate and Cd(II)-iodide systems Serrano, N.; Díaz-Cruz, J. M.; Ariño, C.; Esteban, M.; Puy Llorens, Jaume; Companys Ferran, Encarnació; Galceran i Nogués, Josep; Cecilia Averós, Joan (Elsevier, 2007)A new mathematical treatment has been developed and implemented in an EXCEL spreadsheet in order to determine average equilibrium functions from the full set of data measured by scanning stripping chronopotentiometry (SSCP) ...
Voltammetric currents for any ligand-to-metal concentration ratio in fully labile metal-macromolecular complexation. Easy computations, analytical properties of the currents and graphical method to estimate the stability constant Galceran i Nogués, Josep; Cecilia Averós, Joan; Salvador, José; Monné Esquerda, Josep; Torrent, Marià; Companys Ferran, Encarnació; Puy Llorens, Jaume; Garcés, Josep Lluís; Mas i Pujadas, Francesc (Elsevier, 1999)In order to enable a wider use of voltammetric methods in speciation analysis, it is convenient not to be restricted by ligand excess conditions. This work assumes labile ideal complexation of a metal ion by a ligand, ...
Galceran i Nogués, Josep; Companys Ferran, Encarnació; Puy Llorens, Jaume; Cecilia Averós, Joan; Garcés, Josep Lluís (Elsevier, 2004)AGNES (absence of gradients and Nernstian equilibrium stripping) is a stripping technique consisting of two conceptual steps: (i) application of a potential program (e.g. a step at a fixed potential) generating a known ...