Mani Sivakumar

Facile synthesis of MnO2/carbon nanotubes decorated with a nanocomposite of Pt nanoparticles as a new platform for the electrochemical detection of catechin in red wine and green tea samples

Herein, we report a simple and facile synthesis strategy of MnO2/carbon nanotubes decorated with a nanocomposite of Pt nanoparticles using a simple electrodeposition method. The Pt/MnO2/f-MWCNT modified electrode were characterized by several analytical and spectroscopy techniques and were adopted as a composite for a novel catechin sensor. The as-prepared Pt/MnO2/f-MWCNT modified glassy carbon electrode (GCE) exhibited a smaller peak potential separation (ΔEp), and electron transfer kinetics during the oxidation reaction of catechin. This can be attributed to the larger effective surface area, greater porosity, and more reactive sites on the Pt/MnO2/f-MWCNT-modified GCE. Notably, we achieved a very low detection limit (under optimized conditions) of catechin ca. 0.02 μM (S/N = 3); the linear range is 2-950 μM with excellent sensitivity. The real time application of catechin in red wine, black tea, and green tea samples with excellent performance. The proposed sensor was successfully developed and the advantages of low cost, ease of preparation, long-term stability, and good reproducibility were demonstrated which are superior to recently reported modified electrodes, thereby enabling practical industrial applications.

One pot synthesis of CeO2 nanoparticles on a carbon surface for the practical determination of paracetamol content in real samples

Using the effect of interactions between metal oxides and carbon materials is considered an attractive way to make novel composites for electrochemical sensor applications. Both metal oxides and carbon materials have good electrocatalytic properties that can be used for the sensing of different components such as organic/inorganic pollutants, drugs and molecules. These sugar base-derived carbon decorated with CeO2 nanoparticles (CeO2–C) was prepared using a one pot synthesis and used for the electrochemical sensing of paracetamol (PA). The as-prepared CeO2–C was characterized using different techniques and electrochemical studies. The resulting calculated values of sensitivity, linear range and limit of detection were 262 μA mM−1 cm−2, 1 μM to 1.2 mM and 0.07 μM, respectively. Eventually, CeO2–C is predicted to be a suitably active material for practical applications.

A facile electrochemical synthesis strategy for Cu2O (cubes, sheets and flowers) microstructured materials for sensitive detection of 4-nitrophenol

Herein, we report a facile electrochemical synthesis strategy for Cu2O (cubes, sheets and flowers) microstructured materials deposited on a glassy carbon electrode (GCE) surface as a sensor for the electrochemical detection of toxic 4-nitrophenol (4-NP). The prepared films are characterized by using a variety of techniques, such as SEM, EDX, XRD and XPS. Notably, the proposed sensor exhibits excellent analytical parameters, such as wide linear range, high sensitivity with good detection limit, with values of 0.006–2.72 mM, 197.7 μA mM−1 cm−2 and 0.5 μM, respectively. These results reveal that the Cu2O-modified GCE is suitable for the detection of 4-NP owing to its low cost and simple electrode preparation process. Furthermore, the modified electrode was successfully applied for the detection of 4-NP in various water samples with acceptable results and could act as a practical platform in several industrial practical applications.

Lignocellulosic biomass-derived, graphene sheet-like porous activated carbon for electrochemical supercapacitor and catechin sensing

We synthesize graphene sheet-like porous activated carbon (GPAC) with a high specific surface area by using Bougainvillea spectabilis as a precursor with the assistance of a facile and reliable chemical activation method. The as-synthesized GPAC materials were characterized with a variety of physico-chemical and analytical techniques to investigate their structural and porous properties. In addition, we apply the synthesized GPAC as an electrode material for supercapacitor and catechin sensing, and corresponding electrochemical studies were carried out using cyclic voltammetry, galvanostatic charge–discharge and differential pulse voltammetry. For supercapacitor application, the GPAC exhibits a specific capacitance of 233 F g−1 (at a current density of 1.6 A g−1) and an energy density of 7.2 W h kg−1 (for a symmetric cell). For the sensing application, the GPAC exhibits sensitive detection of catechin (CA). We achieved good sensitivity, an extensive linear range, and a low limit of detection for the CA sensor, with values of 7.2 μA μM−1 cm−2, 4–368 μM, and 0.67 μM, respectively. We further test the GPAC sensor in green tea leaves for real time CA detection. This work demonstrates the successful conversion of waste biomass to useful electrochemical devices.

Simple synthesis of cobalt sulfide nanorods for efficient electrocatalytic oxidation of vanillin in food samples.

Well-defined CoS nanorods (NR) were synthesized using a simple hydrothermal method, and were tested as an electrode material for electro-oxidation of vanillin. The NR material was characterized with regard to morphology, crystallinity, and electro-activity by use of appropriate analytical techniques. The resulting CoS NR@Nafion modified glassy carbon electrode (GCE) exhibited efficient electro-oxidation of vanillin with a considerable linear range of current-vs-concentration (0.5-56μM vanillin) and a detection limit of 0.07μM. Also, food samples containing vanillin were studied to test suitability for commercial applications.

One-step synthesis of porous copper oxide for electrochemical sensing of acetylsalicylic acid in the real sample

A Facile approach of one-step synthesis was employed to prepare porous CuO at different annealing temperature and characterized by using numerous analytical techniques. Moreover, the electrochemical sensing application of CuO modified glassy carbon electrode was studied and recorded using various electrochemical techniques. From the results, it was interpreted that the CuO prepared at 350°C exhibits satisfactorily electrochemical determination of Acetylsalicylic acid (ASA) with unique sensitivity, linear range and limit of detection of about 831.65µA mM-1cm-2, 0.1-714µM and 0.037µM respectively. The proposed sensor also shows good electrocatalytic performance in real sample analysis with acceptable results.

Facile synthesis of perovskite-type NdNiO3 nanoparticles for an effective electrochemical non-enzymatic glucose biosensor

The detailed facile synthesis and material characterizations of NdNiO3 nanoparticles for a non-enzymatic glucose sensor application were discussed briefly in this paper. The NdNiO3 nanoparticles that were prepared by facile synthesis show unique properties with excellent electrochemical performance and exhibit a low detection limit, as low as 0.3 μM, with an ultra-high sensitivity of 1105.1 μA mM−1 cm−2. They were commercially suitable for real-time application in a non-enzymatic glucose sensor.