An ion-gate response of the glutathione monolayer assembly formed on a gold electrode

Voltammetry and EQCM Investigation of Glutathione Monolayer and Its Complexation with Cu2+

“…It corresponded with the reports by others [7,8]. The reason may lie on that the larger cation of tetrabutyl ammonium permeates into the film with more difficulty than other smaller cations, such as K .…”

“…When other metallic ions were added into the solution of 0.01 mol L À1 TBAB, the voltammetry experiment was also performed (the CVs are not shown here). It was found that the metallic ions of Zn ), could not bring about the similar redox peaks as in Figure 4 because they could not be reduced in the potential region from À 0.1 to 0.6 V. They seem not interfere with the determination of Cu 2 , although the complexion is not avoided [5,7].…”

“…The permeation of ions or molecules into the monolayer is attractive and has been studied widely [5,6]. The polar terminate head of the filmforming molecule is the key to bring about the ion-gate response of the film, which can be activated by proton or by metallic ions in the solution [7,8]. Sometimes, it can also be activated by some surfactants, as reported by us [9].…”

“…It suggests that the complexation in the resulting film is destroyed due to the protonation of all the carboxyl terminates in GSH film because the protonating of the group makes it difficult to form the complex GSH-Cu [6,7]. As for the solution of 1.0 mmol L À1 HClO 4 , the corresponding redox peak currents are small, as shown in Figure 5 (dotted line 2), which comes from the deprotonation of one carboxyl acid group whereas another not in each GSH molecule.…”

Electrochemical Studies of Derivatized Thiol Self-Assembled Monolayers on Gold Electrode in the Presence of Surfactants

“…An impedance method to evaluate the ionization of acidic and basic groups in surface confined monomolecular films was reported by Schweiss 16 and his colleagues. Takehara et al [17][18][19][20] carried out seriate studies by cyclic voltammetry (CV) on the permeation properties regulated by the solution pH value, lanthanide and alkaline earth metal ions on glutathione and cysteine-containing dipeptide monolayer modified gold electrode. However, the experimental techniques that they used were not the best choice.…”