Mani Govindasamy

Bio: Mani Govindasamy is an academic researcher from National Taipei University of Technology. The author has contributed to research in topics: Electrochemical gas sensor & Graphene. The author has an hindex of 31, co-authored 74 publications receiving 2144 citations. Previous affiliations of Mani Govindasamy include Bishop Heber College.

Methyl parathion detection in vegetables and fruits using silver@graphene nanoribbons nanocomposite modified screen printed electrode

Abstract: We have developed a sensitive electrochemical sensor for Organophosphorus pesticide methyl parathion (MP) using silver particles supported graphene nanoribbons (Ag@GNRs). The Ag@GNRs nanocomposite was prepared through facile wet chemical strategy and characterized by TEM, EDX, XRD, Raman, UV-visible, electrochemical and impedance spectroscopies. The Ag@GNRs film modified screen printed carbon electrode (SPCE) delivers excellent electrocatalytic ability to the reduction of MP. The Ag@GNRs/SPCE detects sub-nanomolar concentrations of MP with excellent selectivity. The synergic effects between special electrocatalytic ability of Ag and excellent physicochemical properties of GNRs (large surface area, high conductivity, high area-normalized edge-plane structures and abundant catalytic sites) make the composite highly suitable for MP sensing. Most importantly, the method is successfully demonstrated in vegetables and fruits which revealed its potential real-time applicability in food analysis.

Molybdenum disulfide nanosheets coated multiwalled carbon nanotubes composite for highly sensitive determination of chloramphenicol in food samples milk, honey and powdered milk.

Abstract: We have described a hybrid material that consists of molybdenum disulfide nanosheets (MoS 2 ) coated on functionalized multiwalled carbon nanotubes ( f -MWCNTs) for sensitive and selective determination of chloramphenicol (CAP). The MoS 2 / f -MWCNTs nanocomposite was successfully prepared through a hydrothermal process and its structure was characterized by scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, electrochemical impedance spectroscopy and cyclic voltammetry. The MoS 2 / f -MWCNTs nanocomposite holds excellent electrochemical properties and it displays excellent electrocatalytic ability to CAP. Under optimized working conditions, the nanocomposite film modified electrode responds linearly to CAP in the concentration range of 0.08–1392 μM. The detection limit was obtained as 0.015 μM (±0.003). The electrode has high level of selectivity in presence of large excess concentrations of interfering species. In addition, the modified electrode offers satisfactory repeatability, reproducibility and stability. The practical applicability of the electrode was demonstrated in food samples such as, milk, powdered milk and honey samples and the recoveries are agreeable which clearly revealed its practical feasibility in food analysis.

Green synthesized gold nanoparticles decorated graphene oxide for sensitive determination of chloramphenicol in milk, powdered milk, honey and eye drops.

Abstract: A simple and rapid green synthesis using Bischofia javanica Blume leaves as reducing agent was developed for the preparation of gold nanoparticles (AuNPs). AuNPs decorated graphene oxide (AuNPs/GO) was prepared and employed for the sensitive amperometric determination of chloramphenicol. The green biosynthesis requires less than 40s to reduce gold salts to AuNPs. The formations of AuNPs and AuNPs/GO were evaluated by scanning electron and atomic force microscopies, UV-Visible and energy dispersive X-ray spectroscopies, X-ray diffraction studies, and electrochemical methods. AuNPs/GO composite film modified electrode was fabricated and shown excellent electrocatalytic ability towards chloramphenicol. Under optimal conditions, the amperometric sensing platform has delivered wide linear range of 1.5-2.95μM, low detection limit of 0.25μM and high sensitivity of 3.81μAμM(-1)cm(-2). The developed sensor exhibited good repeatability and reproducibility, anti-interference ability and long-term storage stability. Practical feasibility of the sensor has been demonstrated in food samples (milk, powdered milk and honey) and pharmaceutical sample (eye drops). The green synthesized AuNPs/GO composite has great potential for analysis of food samples in food safety measures.

3D graphene oxide-cobalt oxide polyhedrons for highly sensitive non-enzymatic electrochemical determination of hydrogen peroxide

Abstract: Polyhedrons structured cobalt oxide (Co3O4 PHs) and three-dimensional graphene oxide encapsulated cobalt oxide polyhedrons (3D GO-Co3O4 PHs) were synthesized via facile hydrothermal synthetical route for the highly sensitive determination of hydrogen peroxide (H2O2). The morphological study clearly revealed the polyhedron shaped Co3O4 and additionally elemental, diffraction, and electrochemical studies were performed to verify the structure and shape. Owing to excellent synergy between Co3O4 PHs and GO, the composite possesses good porosity, large electrochemical area, roughened surface, and excellent electrocatalytic ability. The development of highly sensitive sensor is essential for H2O2 due to its great significance in physiological, biochemical, pharmaceutical and medicinal applications. A rapid, sensitive, selective, reproducible, and durable non-enzymatic H2O2 assay, by employing 3D GO-Co3O4 PHs modified electrode was described. The sensor offered excellent sensitivity with detection limit of 15 nM, which is superior to those of previously reported sensors. A real-time analysis was demonstrated in commercially acquired contact lens and disinfectant cleaning solutions without pre-treatment.

Flexible Graphene-Based Wearable Gas and Chemical Sensors

Abstract: Wearable electronics is expected to be one of the most active research areas in the next decade; therefore, nanomaterials possessing high carrier mobility, optical transparency, mechanical robustness and flexibility, lightweight, and environmental stability will be in immense demand. Graphene is one of the nanomaterials that fulfill all these requirements, along with other inherently unique properties and convenience to fabricate into different morphological nanostructures, from atomically thin single layers to nanoribbons. Graphene-based materials have also been investigated in sensor technologies, from chemical sensing to detection of cancer biomarkers. The progress of graphene-based flexible gas and chemical sensors in terms of material preparation, sensor fabrication, and their performance are reviewed here. The article provides a brief introduction to graphene-based materials and their potential applications in flexible and stretchable wearable electronic devices. The role of graphene in fabricating ...

Nanocomposites of graphene and graphene oxides: Synthesis, molecular functionalization and application in electrochemical sensors and biosensors. A review

Abstract: Functionalized nanocomposites based on various type of graphene nanomaterials including graphene, graphene oxides (GOs), and doped graphene (oxides) are widely used as materials for various sensors that can display high sensitivity, selectivity and stability. This review with 347 references summarizes advances in the preparation and functionalization of graphene nanocomposites for the application of electrochemical sensors and biosensors. Following a general introduction into the field, the article is divided into subsections on (a) the synthesis and functionalization of nanocomposites (made from graphene, various kinds of GOs, heteroatom-doped GOs), (b) on methods for functionalization of composites (with other carbon nanomaterials, metal nanoparticles, metal oxide and metal sulfide nanoparticles), (c) on functionalization with inorganic materials including polyoxometalates, hexacyanoferrates, minerals), (d) on functionalization with organic materials such as amino acids, surfactants, organic dyes, ionic liquids, macrocycles (including cyclodextrins, crown ethers and calixarenes), and (e) on functionalization with organometallics and with various other organic compounds, (f) on functionalizations with polymers such as conventional polymers, polyelectrolytes, conducting polymers, molecularly imprinted polymers, (g) on functionalization with biomolecules including proteins and nucleic acids. Other subsections cover flexible graphene and GO based nanocomposites and 3D composites. Application of graphene and GO nanocomposites are then covered in a in large section that comprises electrochemical sensors and biosensors (based on voltammetry, amperometry, potentiometry, impedimetry, electrochemiluminescence, photoelectrochemistry, field effect transistors, electrochemical immunosensors) with specific subsections on gas sensors, enzymatic biosensors and gene sensors. A concluding section covers current challenges and perspectives of graphene and GO based (bio)sensing.