Graphene and ionic liquids new gel paste electrodes for caffeic acid quantification

Abstract

Graphene/ionic liquids nanocomposite gels were synthesized by an electrochemical etching approach and fully characterized under a morphological and structural point of view. For this purpose, several analytical techniques were applied, as HR-TEM/EDX (High Resolution-Transmission Electron Microscopy/Energy Dispersive X-Ray Analysis); FE-SEM/EDX (Field Emission-Scanning Electron Microscopy/Energy Dispersive X-Ray Analysis); XPS (X-Ray Photoelectron Spectroscopy); FT-IR (Fourier Transform-Infrared Spectroscopy) and electrochemical techniques. After the characterization study, nanocomposite-gel paste electrodes were assembled, exhibiting a selective and specific detection toward the caffeic acid oxidation. Better performances in terms of linear range of concentration (from 0.025 to 2.00 M), reproducibility (intra-; 1.40% and inter-electrode reproducibility-3.20%), sensitivity (3389/μA mM-1 cm-2), fast response time (2 s) and detection limit (0.005 mM) were obtained, in comparison with other chemically modified electrodes, described in literature for the caffeic acid detection. This nanocoposite-gel could represent a new prototype of miniaturized nanostructured sensors useful for the "in situ" quantification of an important molecule, having pharmacological properties, anti-inflammatory, antibacterial, antiviral, immunomodulatory and antioxidant effects.