Digital Harmonic Analysis of Cadmium Ion Reduction on a Dropping Mercury Electrode

The cadmium ions reduction on a mercury electrode is investigated. A sinusoidal voltage perturbation signal, superimposed on a linearly changing dc potential, is used. A total time–frequency analysis of the polarographic current of cadmium ions reduction on a dropping mercury electrode is performed. Classical Fourier transform leads to decomposition of the polarographic current into its harmonics. The current harmonics determined by Fourier transform are potential-independent. The STFT transform of the polarographic current also leads to its decomposition into harmonics. However, application of the STFT transform correctly reflects changes in the current harmonics as the function of potential.