engleski

ELECTROCHEMICAL BEHAVIOR OF NATURAL REDUCERS ON CARBON NANOMATERIALS: A CONTRIBUTION TO THE OPTIMIZATION OF ELECTROANALYTICAL METHODS

Nowadays, the determination of polyphenols has become an important target due to their biological activities and the role of their importance for food and beverages quality [1]. As electrochemically active compounds, the behaviour of polyphenols can be easily electrochemically monitored [2, 3]. This can be useful in the evaluation of the mechanism involved in the stability, their reducing activity and other aspects of their redox behaviour. Many articles, related to polyphenols electrochemical behaviour on carbon nanomaterials modified electrodes, [4, 5], can be found, sometimes controversial results have been published. This is not surprising since polyphenols redox behaviour depends not only on the chemical structure of polyphenols but also on factors such as kind of used carbon nanomaterials, mechanism of the reaction, pH, support solution, time, presence of oxygen, the concentration of polyphenols, etc. Therefore, it is necessary to consolidate information of the electrochemical behaviour of polyphenols depending on various factors. As a part of the large study of the electrochemical behaviour of polyphenols (non-flavanoids and flavanoids), here we present results of the investigation related to the electrochemical behaviour of gallic acid and quercetine onto glassy carbon electrode (GCE), modified with different carbon nanomaterials (CNM) such as graphene, electrochemically reduced graphene oxide, single-walled carbon nanotubes and multi-walled carbon nanotubes. Results obtained by cyclic voltammetry and electrochemical impedance spectroscopy revealed significant differences in electrochemical kinetic parameters depending on used CNM and its morphology (characterization was performed by scanning electronic microscopy) as well as used support solutions and their composition. Also, parameters obtained with various CNM, at different pH, can be promising for selectivity improvement, as well as in establishing a method of determination. Obtained results offer valuable information useful for the investigators focused on the development of electrochemical sensors for determination of the polyphenols, which can include further modification of the electrodes with various organic or inorganic mediators, various composite materials, etc.

ELECTROCHEMICAL BEHAVIOR ; NATURAL REDUCERS ; CARBON NANOMATERIALS.

Izradu ovog rada potpomogla je Zaklada Hrvatske akademije znanosti i umjetnosti.