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Development and design of the nanocomposite fabricated pencil graphite electrode with higher selectivity, low cost, and desirable stability are required to increase the detection ability of the voltammetric sensors. In the present study, molybdenum sulfide–reduced graphene oxide (MoS2-rGO) nanocomposite fabricated pencil graphite electrode (MoS2-rGO/PGE) was developed to study the electro-kinetic behavior of the antidepressant medicine paroxetine. A simple one-step and cost-effective hydrothermal method was used to synthesize the micro-flowers of MoS2 and MoS2-rGO composite. The XRD, Raman spectroscopy, SEM, and TEM techniques are utilized to characterize the morphology and microstructure of the prepared MoS2-rGO, which revealed the distribution of the MoS2 micro-flowers over rGO flakes that enhance the electro-catalytic activity of MoS2-rGO/PGE. The irreversible electro-oxidation of the paroxetine at MoS2-rGO/PGE vs. Ag/AgCl electrode is diffusion controlled but also affected slightly by the adsorption process. The different electrochemical quantities such as heterogeneous rate constant (Kh = 5.0 × 10−3cms−1), charge transfer coefficient (α = 0.69), diffusion coefficient (Do = 6.98 × 10−4cm2s−1), surface coverage (Γo = 1.77 × 10−9 molcm−2), and effective electrode surface area (A = 0.0419 cm2) were reported. Advanced differential pulse and square wave voltammetry (DPV and SWV) were utilized for the quantification of the paroxetine in pharmaceutical samples with a linearity range of 0.5 to 2.5 and 0.5 to 3.1 μM with LOD values of 0.46 and 0.42 μM, respectively. The lower values of LOD, LOQ, and RSD% make DPV and SWV viable electro-analytical methods for the sensitive, cost-effective, and eco-friendly detection of the antidepressant drug paroxetine employing MoS2-rGO/PGE probe. [ABSTRACT FROM AUTHOR]

The fast, accurate, and affordable determination of the anti-epileptic drug levetiracetam (LEV) is the need of time for human health. In this study, a novel electrochemical sensor platform was proposed for the cost-effective and sensitive determination of the levetiracetam based on molybdenum sulfide nano-flower-adorned pencil graphite electrode (MoS2/PGE). The nano-flowers of MoS2 were prepared by a cost-effective one-step facile hydrothermal method and the morphology of synthesized MoS2 micro-flowers was characterized via FESEM, XRD, and EDS techniques. The various electro-kinetics parameters like diffusion coefficient (Do =1.41 × 10−5 cm2 s−1), heterogeneous rate constant (Kh= 9.04 × 10−4 cm s−1), electron transfer coefficient (α = 0.66), the effective surface area of the fabricated electrode (A = 0.0767 cm2), and surface coverage (Γo = 2.98 × 10−11 mol cm−2) were evaluated for the oxidation of LEV at MoS2/PGE employing voltammetric techniques. The oxidative peak current in the optimized square wave stripping voltammetry varies linearly with LEV concentration within the range of 72.0 to 130.0 µM with detection limit (LOD) value of 14.20 µM. The proposed MoS2/PGE platform provides a sensitive, low cost and eco-friendly tool for the rapid detection of LEV in clinical samples. [ABSTRACT FROM AUTHOR]

First time, the electro-oxidative behaviour and determination of acotiamide at a pencil graphite electrode have been investigated under different experimental conditions using cyclic voltammetry (CV), differential pulse anodic stripping voltammetry (DPASV), and square wave anodic stripping voltammetric (SWASV) techniques. The voltammetric responses of acotiamide have been analyzed at different scan rates, pH and concentrations. Oxidation of acotiamide at the surface of pencil graphite electrode gave two well defined irreversible peaks in the voltammograms in BR buffer of pH 7.0. The oxidation process is completely diffusion controlled. A linear response of peak current has been obtained between 15.5 to 124 μM in non-aqueous media for all the voltammetric techniques. The proposed DPASV and SWASV techniques show limit of detection at 18.58 and 13.36 μM, respectively. [ABSTRACT FROM AUTHOR]