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

• Published in: Sensors and actuators. B, Chemical Chemical, 2015-06, Vol.212, p.248-255
• Main Authors: Valentini, Federica, Roscioli, Davide, Carbone, Marilena, Conte, Valeria, Floris, Barbara, Bauer, E.M., Ditaranto, Nicoletta, Sabbatini, Luigia, Caponetti, E., Chillura-Martino, D.
• Format: Article
• Language: English
• Subjects: Anti-oxidant agents; Caffeic acid; Electrochemistry; Electrodes; Energy dispersive; Graphene; Ionic liquids; Nanocomposites; Nanostructure; Pastes; Sensors; X-rays
• ISSN: 0925-4005; 1873-3077
• DOI: 10.1016/j.snb.2015.02.033

•The nanocomposite based on graphene and ionic liquids is prepared in only one-step by an electrochemical etching of a anode graphite rod, that work as a sacrificial working electrodes.•The functionalization of the nanocomposites is achieved by only one step avoiding further manipulation of the nanomaterials that could imply a loss of materials for subsequent experiments.•The resulting gel phases is very suitable for the assembly of miniaturized chemically modified sensors, selective and specific for the detection of caffeic acid (an important anti-oxidant molecule).•The high selectivity of the resulting sensors could be very promising, in the future, for the assembly of miniaturized and automatized sensors to use in complex matrices. 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 2.00M), reproducibility (intra-; 1.40% and inter-electrode reproducibility-3.20%), sensitivity (3389/μAmM−1cm−2), fast response time (2s) and detection limit (0.005mM) 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.