Comparative Electroanalytical Studies of Graphite Flake and Multilayer Graphene Paste Electrodes

Abstract

In this paper, the fabrication, surface characterisation and electrochemical properties of graphite flake (GFPE) and multilayer graphene (MLGPE) paste electrodes are described. The Raman investigations and scanning electron microscopy were used to analyze and compare structure of both carbon materials. The electroanalytical performance of both electrodes was examined and compared on the basis of the square-wave and cyclic voltammetric behavior of acetaminophen and model redox systems. Results of those studies revealed that GFPE has a larger electroactive surface area and better conductive properties, whilst MLGPE demonstrate better analytical characteristic in case of acetaminophen (AC) determination. AC determination was developed using square wave voltammetry (SWV) and square wave stripping voltammetry (SWSV). For both working electrodes, the process of accumulation enabled us to obtain an extended linear range and to lower the detection limit. In pharmaceutical formulations, AC was determined with good recovery.Sensors 2020, 20, 1684 2 of 15 anisotropic thermal conductivity, with high conductivity in the horizontal direction and low thermal conductivity in the vertical direction [20]. Graphite flakes have found application in electrochemistry as, for instance, a promising anode material for lithium ion batteries [21]. GFs have unique features, including excellent strength and high fracture toughness [22]. Furthermore, the layered graphite structure and weak forces between the layers lead to the possibility of easily refreshing the surface of a paste electrode made of graphite flakes. These properties make graphite flake a promising electrode material [23].Recently, graphene is considered the material of the "rising star" and has received attention due to its unique properties. This form of carbon is considered as a prototype of two-dimensional carbon system and all other dimensionalities [5,24,25]. Graphene can be wrapped into fullerenes (0D), rolled into carbon nanotubes (1D), or used to create graphite (3D) [24]. The development of knowledge related to graphene led to the creation of graphene-based materials. Multilayer graphene (MLG) is a 2D nanomaterial composed of stacked monolayers of graphene. Importantly, both MLG and GNP (graphene nanoplatelets) are composed of graphene layers arranged on top of each other. However, they differ in the number of layers and properties. The number of graphene layers in GNP is greater than 10, while that in MLG varies from 11 to 21 [26]. Experiments show that for model redox systems there is no strong correlation between the flake thickness and the electron transfer rate [27]. However, a higher electron transfer was achieved for flakes consisting of less than 20 graphene layers [27]. The properties of MLG are more similar to those of graphene than to those of graphite [26], and thus make MLG a promising material for the fabrication of carbon paste electrodes.Acetaminophen (AC) is very commonly used in many diseases and pain treatment. Because of its antipyretic and analge...

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