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This paper presents a method for the construction of a graphene paste electrode (GPE) from reduced graphene oxide (RGO). The GPE was successfully used for the determination of medetomidine. The influence of some experimental variables such as pH, supporting electrolyte, scan rate, and possible interferences were studied. Differential pulse voltammetric (DPV) peak currents of medetomidine increased linearly with its concentration in the range from 0.009 to 2.5 µM. The limit of detection ( LOD) and limit of quantitation ( LOQ) values for the determination of medetomidine were 2.8 and 9.2 nM, respectively. Also, for the first time, the electroreduction behavior of medetomidine was investigated. [ABSTRACT FROM AUTHOR]

Abstract: Graphene is ideally suited for implementation in electrochemical applications due to its reported large electrical conductivity, large surface area, unique heterogeneous electron transfer rate, and low production cost. This paper presents a method for the construction of graphene paste electrode (GPE) from reduced graphene oxide (RGO). Direct electrochemical detection of drug is of high importance in analytical chemistry. Here, the GPE was successfully used for the determination of acetazolamide (ACZ). So, the influence of some experimental variables such as working solution pH, supporting electrolyte, scan rate, pulse amplitude, and possible interferences were studied. The proposed sensor exhibited a high sensitivity and good selectivity, and it was applied for clinical evaluation of ACZ. [Copyright &y& Elsevier]

Abstract: This work describes a novel type of working electrode for use in voltammetry methods. Graphene is ideally suited for implementation in electrochemical applications due to its reported large electrical conductivity, large surface area, unique heterogeneous electron transfer rate, and low production costs. This paper presents a method for the construction of graphene paste electrode (GPE) from graphene. The GPE is not needed to be modified, because the surface of graphene is functionalized. Direct electrochemical detection of drug is of high importance in analytical chemistry. Here, the GPE was successfully used for the determination of chlorpromazine. [Copyright &y& Elsevier]

The glucose-capped CdSe quantum dots (QDs) and 1-ethyl-3-methyl-imidazolium:PF 6 (EtMIMPF 6 ) ionic liquid (IL) have been incorporated in the graphite paste electrode (GPE) and used for the voltammetric determination of minoxidil. The high permeability of IL as a hydrophilic binder to polar species, in addition to improving the faradaic current, resulted in increased capacitive current. In order to further improvement of the faradaic signal, we employed a glucose-capped CdSe QDs. Cyclic voltammetry and Faradaic impedance spectroscopy (FIS) indicated that incorporating the QDs into the composite matrix although was not able to significantly improve the kinetics of minoxidil oxidation, but remarkably enhanced the magnitude of the anodic peak current. The sluggish expansion of diffusion layer in viscose IL medium and the microdisc-geometry like behaviour of nanoparticles provided a proper condition for transition from the planar semi-infinite diffusion to the thin layer behaviour. Density functional theory (DFT) was found to yield a good description of the enhancement of signal in the presence of nanomaterials. The results of calculation support that the change in diffusion manner, and not improving in the electron transfer capability at electrode/electrolyte interface, is responsible for the observed signal enhancement. A detailed mechanism for oxidation of minoxidil was also proposed. [ABSTRACT FROM AUTHOR]