New procedures for voltammetric determination of copper (II) using antimony film-coated carbon paste electrodes

Two new procedures were elaborated to determine copper (II) using voltammetry at the antimony film carbon paste electrodes (SbF-CPEs). In the first one, copper (II) was accumulated from a medium of 0.01 M hydrochloric acid at -1.2 V for 120s and, after a equilibration step of 15s, followed with an anodic stripping using 25 Hz frequency, 25 mV amplitude and 4 mV potential step. Calibration dependence was linear up to 120 ppb Cu, detection limit (3 sigma) of 1.45 ppb was calculated. In the second procedure, Pyrocatechol Violet was used as a chelating ligand. In the same medium, potential of -0.5 V and time of 60s were used for accumulation, then followed with equilibration and anodic stripping steps as mentioned for the first procedure. In this case, calibration was linear up to 100 ppb Cu with detection limit of 1.10 ppb, a slightly lower value even if half time of accumulation was used. Both procedures were verified in analysis of a real river water sample giving results comparable with those obtained by ICP-MS method. (C) 2011 Elsevier Ltd. All rights reserved.