Modification of a Polycrystalline Gold Electrode by Thiolated Calix[4]arene and Undecanethiol: Self-assembly Process versus Electrochemical Deposition
Abstract
Modification of the surface of a polycrystalline gold substrate with thiol compounds has been studied in order to evaluate the possibilities of designing ion-selective electrochemical sensors on this basis. The results of detailed voltammetric and impedance measurements, obtained with gold surfaces modified by self-assembly procedures and by electrochemical deposition of the modifiers are thoroughly discussed and critically compared with those published in the literature.
It can be concluded that there are certain possibilities of selective measurements in these systems, but that the spatial heterogeneity of the polycrystalline gold surface seriously limits the applicability and reliability of the system. Therefore, it is expected that substantially better results will be obtained with single-crystal gold substrates and the study in this direction is in progress.