Construction of Ionic Liquid Self-assembled Monolayer on Gold Electrode for Hemoglobin Modifying and Peroxide Biosensing

We constructed a self-assembled monolayer (SAM) of mercaptoacetic acid combining functionalized ionic liquid (IL-MAA) by covalent interaction on gold electrode. The formation of IL-MAA SAM on gold electrode has been confirmed by Fourier transform infrared spectroscopy (FT-IR), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) in this article. The results of CV and EIS revealed that the electrochemical behavior of the [Fe(CN)(6)](3-/4-) redox couple probe improved along with IL's introduction on gold electrode. As IL-MAA is electroactive, hemoglobin (Hb) was modified on the IL-MAA SAM gold electrode subsequently and the direct electrochemistry of Hb was realized. UV-vis spectrum illustrated that the Hb absorbed on the SAM film maintained its natural activity. Upon the optimal conditions, the modified electrode exhibited a high electrocatalytic activity to hydrogen peroxide. Accordingly, an easily-made and cost-effective hydrogen peroxide electrochemical biosensor, accompany with proper fine quality, was accomplished. More importantly, the methodology could provide an effective enzyme immobilization platform based on ionic liquid modifying electrode surface and broaden the use of functionalized ionic liquid in electrochemical biosensor field.