engleski

Cathodic stripping voltammetry of the copper-1, 10-phenanthroline complex

Cathodic stripping voltammetry of copper, based on the accumulation and reduction of its complex with 1, 10-phenanthroline (phen), has been studied. The complex is reduced in two steps from CuI-phen and CuII-phen to copper amalgam at potentials of -0.43 and -0.62 V vs. Ag/AgCl, respectively. The reduction processes are strongly dependent on the pH of the solution, as well as on the concentration of the metal ion and ligand. The reduction mechanism of both complexes was established. The detection limit for copper in 0.55 mol/LNaCl with 20 min accumulation at 0.0 V vs. Ag/AgCl, measuring the reduction peak of the CuI-phen complex at -0.43 V vs. Ag/AgCl by SWV, was found to be about 5 × 10-10 mol/L. The reaction parameters were calculated by square-wave voltammetry (SWV), i.e., transfer coefficients CuI-phen = 0.31 and CuII-phen = 0.45, and the maximum surface concentrations CuI-phen = (2.02 ± 0.08) × 10-11 mol/cm2 and CuI-phen = (2.83 ± 0.12) × 10-12 mol/cm2. Measurements of the copper content in natural seawater samples were performed as well.

copper ; stripping voltammetry ; speciation

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