Direct Covalent Modification of Glassy Carbon Surfaces with 1-Alkanols by Electrochemical Oxidation

The modification of a glassy carbon (GC) electrode with an alkanol by electrochemical oxidation was examined. When a GC electrode was oxidized by multiple potential sweep between 0 and 2.0V vs. Ag wire in 1-octanol containing H2SO4 (1M), the electrode was modified with octanol, probably through an ether linkage, as judged from the voltammetric behavior of Fe(CN)3-6 and catechol at the treated electrode, which closely resembled that at a long-chain alkanethiol-modified gold electrode. In the modification, the potential range and the sweep rate affected the extent of linking of the alcohol to the surface, and a potential sweep at 10mV/s from 0 to 2.0V gave a GC electrode tightly covered with the alcohol. The membrance thus formed on the GC electrode was stable not only to applied potential bias over the range from -0.5 to 1.5V vs. SCE (saturated calomel electrode) in 0.1M aqueous NaCl solution but also to sonication in H2O and MeOH. n-Alkanols of various chain lengths were also used to modify a GC electrode. The depression of the electrode process of Fe(CN)3-6 at the modified electrodes was enhanced as the carbon number in the modifiers increased.