Morphine is a powerful opioid pain medication and commonly used narcotic pain killer and is toxic during overdose or when abused. Compared to conventional analytical techniques, the electroanalytical method has significant advantages viz. low cost, simplicity, ease of operation and facile miniaturization. In the present paper different approaches based on various modifications adopted for effective electrochemical sensing of morphine are reviewed in a comprehensive way. Among different modified electrodes available for the detection of morphine, carbon based materials—CNTs and graphene—display effective quantification and are attractive in terms of cost compared to noble metals. In addition, the performance of reported sensors in terms of their including detection range (LDR), limit of detection (LOD) and technique used are presented. The present review compares various electroanalytical techniques adopted for the determination of morphine.

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In the current scenario, there is critical global demand for the protection of daily handling surfaces from the viral contamination to limit the spread of COVID-19 infection. The nanotechnologists and material scientists offer sustainable solutions to develop antiviral surface coatings for various substrates including fabrics, plastics, metal, wood, food stuffs etc. to face current pandemic period. They create or propose antiviral surfaces by coating them with nanomaterials which interact with the spike protein of SARS-CoV-2 to inhibit the viral entry to the host cell. Such nanomaterials involve metal/metal oxide nanoparticles, hierarchical metal/metal oxide nanostructures, electrospun polymer nanofibers, graphene nanosheets, chitosan nanoparticles, curcumin nanoparticles, etched nanostructures etc. The antiviral mechanism involves the repletion (depletion) of the spike glycoprotein that anchors to surfaces by the nanocoating and makes the spike glycoprotein and viral nucleotides inactive. The nature of interaction between the nanomaterial and virus depends on the type nanostructure coating over the surface. It was found that functional coating materials can be developed using nanomaterials as their polymer nanocomposites. The various aspects of antiviral nanocoatings including the mechanism of interaction with the Corona Virus, the different type of nanocoatings developed for various substrates, future research areas, new opportunities and challenges are reviewed in this article.

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Introduction: In this study, solar exfoliated graphite oxide modified glassy carbon electrode was used for the anodic oxidation of epinephrine in a phosphate buffer medium at pH7. The modified electrode showed fast response and sensitivity towards Epinephrine Molecule (EP). The electrode was characterized electrochemically through Cyclic Voltammetry (CV) and Differential Pulse Voltammetry (DPV). Area of the electrode enhanced three times during modification and studies reveal that the oxidation process of EP occurs by an adsorption controlled process involving two electrons. The results showed a detection limit of 0.50 ± 0.01μM with a linear range up to 100 μM. The rate constant calculated for the electron transfer reaction is 1.35 s-1. The electrode was effective for simultaneous detection of EP in the presence of Ascorbic Acid (AA) and Uric Acid (UA) with well-resolved signals. The sensitivity, selectivity and stability of the sensor were also confirmed. Methods: Glassy carbon electrode modified by reduced graphene oxide was used for the detection and quantification of epinephrine using cyclic voltammetry and differential pulse voltammetry. Results: The results showed an enhancement in the electrocatalytic oxidation of epinephrine due to the increase in the effective surface area of the modified electrode. The anodic transfer coefficient, detection limit and electron transfer rate constant of the reaction were also calculated. Conclusion: The paper reports the determination of epinephrine using reduced graphene oxide modified glassy carbon electrode through CV and DPV. The sensor exhibited excellent reproducibility and repeatability for the detection of epinephrine and also its simultaneous detection of ascorbic acid and uric acid, which coexist in the biological system.

The unique properties of graphene blended with palladium deposition were used for sensing application by virtue of its charge transfer properties. Epinephrine (EP) is anodically oxidized on a glassy carbon electrode (GCE) modified by palladium graphene composite in phosphate buffer solution of pH 7. The electrodeposited palladium over the GCE -graphene surface ensures fast electrochemical determination of EP. The electrode served as a sensing platform for the simultaneous voltammetric determination of EP, ascorbic acid (AA) and uric acid (UA). The electrochemical deposition of palladium has greatly enhanced the surface properties. Cyclic voltammetry (CV), differential pulse voltammetry (DPV) and chronoamperometry were used to assess the electrochemical performance. Investigations reveal that the process is adsorption controlled involving two electrons and the average catalytic rate constant is 2.39 × 10 3 M −1 s −1 . Palladium incorporated electrode sensitively determined EP in presence of the usual interferents uric acid (UA) and ascorbic acid (AA) with well resolved peaks at very minute concentrations. DPV method enabled the highest sensitivity of 100nM for EP, 170nM for UA and 22μM for AA. The modified electrode offered excellent performance toward real samples such as blood serum and urine.

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