DETECTION AND RESOLUTION ENHANCEMENT OF 2 CLOSE ELECTROCHEMICAL PROCESSES

The polarograms of two electrode processes whose half-wave potentials are separated by 15-40 mV have been simulated. Under such conditions the polarogram obtained by differential pulse polarography scarcely shows the composite nature of the response. The normalized peak-shaped response is compared to a single process occurring exactly between the two former ones. The shapes of the responses are identical; only their half-peak widths differ. Fourier transforms of the two signals (for a single and two energetically close processes) were performed and they also differ slightly. In the case of a real experiment, this slight difference could easily be attributed to experimental imperfection. By deconvolution of the same data with a similar peak-shaped function (in the Fourier domain this is the simple division of two functions), it is possible to identify already in the Fourier domain whether a single or two energetically close processes are taking place. Inverse transformations give a clear distinction between single and double processes. As an experimental example, differential pulse polarograms of a mixture of Pb2+ and Tl+ in 4 M NaCl were measured. Detection of the composite solution and the necessary conditions are discussed.