Facilitated ion transfer of protonated primary organic amines studied by square wave voltammetry and chronoamperometry

• Facilitated ion transfer of organic protonated amines is studied.
• Cyclic square wave voltammetry is used as main technique.
• Complexation constants and standard ion transfer potentials are determined.
• Diffusion coefficients in the organic and aqueous phases are determined.
• The goodness of square wave voltammetry as analytical tool is shown.

The transfer of the protonated forms of heptylamine, octylamine, decylamine, procaine and procainamide facilitated by dibenzo-18-crown-6 from water to a solvent polymeric membrane has been investigated by using cyclic square wave voltammetry. The experimental voltammograms obtained are in good agreement with theoretical predictions. The values of the standard ion transfer potential, complexation constant and diffusion coefficient in water have been obtained from these experiments, and have been used to draw some conclusions about the lipophilicity of these species and the relative stability of the organic ammonium complexes with dibenzo-18-crown-6. The results have been compared with those provided by linear sweep voltammetry. Calibration graphs were obtained with both techniques. An interesting chronoamperometric method for the determination of the diffusion coefficient of the target ion in the membrane has been developed and applied to all these protonated amines.

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