A General Approach Based on Sampled-Current Voltammetry for Minimizing Electrode Fouling in Electroanalytical Detection
Abstract
Electrochemical analysis of species known to passivate electrode surfaces remains challenging. We previously proposed a new method dealing with sampled-current voltammetry performed on an electrode array to mimic polarography at a dropping mercury electrode for the detection of copper. In this work, we study the effectiveness of this method to circumvent electrode fouling with the analysis of phenol solutions at high concentrations (10-2 mol L-1), known to polymerize on electrode surface during its oxidation. Electrode arrays well-adapted to the analysis with such system are prepared by photolithography and characterized by X-Ray photoelectron spectroscopy, X-ray diffraction and voltammetry. While analyses performed in conventional linear voltammetry or sampled-current voltammetry on a single electrode are considerably affected by electrode fouling, a linear calibration plot was achievable using our method. Modelling of the electrochemical signal showed that the current depends only on the applied potential and a parameter characteristic of the passivation phenomenon. It also underlined that sampled-current voltammetry on electrode array can circumvent the problem of passivation by a judicious choice of the sampling time.
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