Self-assembled monolayer of thiols on gold electrodes prepared by gold electro-chemical deposition on platinum wire [articol]

Abstract

The gold electrodes modified with organic compounds (frequently organic thiols and their derivates), represent a new category of devices which are widely used in molecular recognition, in special in case of biomolecules analysis. Alkanethiols are spontaneously adsorbed on the gold surface and form a monomolecular film, with a highly ordered structure, called a self-assembled monolayer (SAM). This represents a promising approach which offers the possibility of design and assembling desired structures at molecular level. One of the main disadvantages in the utilization of these kinds of electrodes at large scale is the relative high cost of gold electrodes manufactured on specialized companies. Starting from these, we try to obtain the gold electrodes by electro-chemical deposition of gold, on platinum wire. These electrodes can be easily obtained in laboratory, with common laboratory equipments and are not so expensive. The obtained electrodes have been characterized with cyclic voltammetry and electrochemical impedance spectroscopy (EIM). The experimental results have show that the analytical performances of these electrodes (quantity of thiol retained on surface,permeability degree, stability in time of obtained monolayer, etc.) are comparable with those obtained in case of manufactured gold electrodes. The elctrodes have show higher reproducibility in their electrochemical behaviour as well as in their modification, and was prepared to be utilized in the detection of humic acid molecules from environmental samples.