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Graphene-based materials are among the most innovative and promising materials for the development of high-performance sensing devices, mainly due to the large surface area and the possibility to modify their reactivity by suitable functionalization. In the field of sensing applications, the peculiarities of innovative materials can be exploited only if chemical and physical properties are fully understood and correlated with each other. To this aim, in this work, graphene oxide (GO) and ethanol-treated GO (GOEt) were investigated from chemical and structural points of view. Electrical characterization was performed by depositing GO and GOEt between two electrodes by dielectrophoresis. All the investigations were repeated on GO materials after thermal treatment in a low temperature range (60 °C-300 °C). Furthermore, the electrical conductivity of GO was investigated by changing the temperature and the environment (air or N2) during the characterization: an increase in the conductivity of the as-deposited GO was observed when the device is cooled down and this effect is reversible with the temperature. GOEt and the thermally treated GO and GOEt show an opposite trend, confirming the key role of the oxygen functionalities in the conduction mechanisms and, therefore, in the conductivity of the GO layers. [ABSTRACT FROM AUTHOR]

Keywords: chemical analysis; chromatography; mass spectrometry; spectrometry; sampling; environment; biomedicine; pharmaceutics; food EN chemical analysis chromatography mass spectrometry spectrometry sampling environment biomedicine pharmaceutics food 11767 11767 1 12/28/21 20211215 NES 211215 The 12th International Conference on "Instrumental Methods of Analysis" www.ima2021.gr (accessed on 8 November 2021)), was organized by the Aristotle University of Thessaloniki and National Technical University of Athens, during 20-23 September 2021 as a virtual event, providing the opportunity for high-level analytical scientists from all around the world to promote their relevant research. However, in most of the aforementioned approaches, such optimization is focused on specific compounds, or compound classes, known to be present and/or abundant in the corresponding matrices [3,4]. Detection and chemical identification of organic biomarkers require the use of high-sensitivity techniques to overcome the complexity limitations of the samples in terms of composition and low concentrations of constituent compounds. The analysis of autumn heather honey revealed that phenolic compounds are the most abundant and p-anisaldehyde, 1-methoxy-4-propyl-benzene, and p-anisic acid could serve as potent marker compounds. These compounds were distributed in five major categories, namely, hydroxycinnamic acid derivatives (10 compounds), hydroxybenzoic acid derivatives (6 compounds), flavonoids (25 compounds), phenolic terpenes (carnasol and carnosic acid), and chalcones (arbutin). [Extracted from the article]