Significance of data treatment and experimental setup on the determination of copper complexing parameters by anodic stripping voltammetry (CROSBI ID 158731)
Prilog u časopisu | izvorni znanstveni rad | međunarodna recenzija
Podaci o odgovornosti
Omanović, Dario ; Garnier, Cédric ; Louis, Yoann ; Lenoble, Véronique ; Mounier, Stéphane ; Pižeta, Ivanka
engleski
Significance of data treatment and experimental setup on the determination of copper complexing parameters by anodic stripping voltammetry
Different procedures of voltammetric peak intensities determination, as well as various experimental setups were systematically tested on simulated and real experimental data in order to identify critical points in the determination of copper complexation parameters (ligand concentration and conditional stability constant) by anodic stripping voltammetry (ASV). Varieties of titration data sets (Cumeasured vs. Cutotal) were fitted by models encompassing discrete sites distribution of one-class and two-class of binding ligands (by PROSECE software). Examination of different procedures for peak intensities determination applied on voltammograms with known preset values revealed that Tangent Fit (TF) routine should be avoided, as for both simulated and experimental titration data it produced an additional class of strong ligand (actually not present). Peak intensities determination by fitting the whole voltammogram for subtraction of the background current is found to be the most appropriate, as it provided reliable complexation parameters. Tests performed on real seawater samples under different experimental conditions revealed that in addition to importance of proper peak intensities determination, an accumulation time (control of the sensitivity) and an equilibration time needed for complete complexation of added copper during titration (control of complexation kinetics) are the keypoints to obtain reliable results free of artefacts. The consequence of overestimation and underestimation of complexing parameters is supported and illustrated by the example of free copper concentrations (the most bioavailable/toxic specie) calculated for all studied cases. Errors up to 80% of underestimation of free copper concentration and almost two orders of magnitude overestimation of conditional stability constant were registered for the simulated case.
anodic stripping voltammetry ; metal speciation ; copper complexing capacity ; data treatment ; fitting
nije evidentirano
nije evidentirano
nije evidentirano
nije evidentirano
nije evidentirano
nije evidentirano
Podaci o izdanju
664 (2)
2010.
136-143
objavljeno
0003-2670
1873-4324
10.1016/j.aca.2010.02.008