Subbiramaniyan Kubendhiran

Green reduction of reduced graphene oxide with nickel tetraphenyl porphyrin nanocomposite modified electrode for enhanced electrochemical determination of environmentally pollutant nitrobenzene

Nitrobenzene (NB) is widely used in the manufacturing of different types of products and other aromatic chemicals. Moreover, it is highly toxic and environmental pollutant compound. Therefore, the detection of nitro aromatic compounds (NACs) has gained more attention in the field of sensor. This article describes the green reduction utilized to preparation of green reduced graphene oxide/nickel tetraphenyl porphyrin (GRGO/Ni-TPP) nanocomposite modified electrode for the determination of nitrobenzene (NB). The GRGO was prepared by environmentally friendly method and using caffeic acid (CA) as a reducing agent. Moreover, the GRGO/Ni-TPP nanocomposite was prepared via the π-π stacking interaction between the RGO and Ni-TPP. In addition, the prepared material was confirmed by the UV-Visible spectroscopy (UV), nuclear magnetic resonance spectroscopy (NMR) and Fourier transform infrared spectroscopy (FTIR). The structural morphology and elemental composition of the prepared nanocomposite was confirmed by the scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDX). Besides, the electrochemical studies of the prepared nanocomposite was characterized by the CV and DPV technique. The DPV studies displayed the linearity response of the proposed sensor about 0.5-878µM with the sensitivity of 1.277µAµM-1cm-2 and the limit of detection (LOD) is 0.14µM. Furthermore, the GRGO/Ni-TPP nanocomposite modified electrode shows good selectivity towards the detection of NB. In addition, the real sample analysis exhibited appreciable recovery towards the determination of NB using various types of water samples.

A non-covalent interaction of Schiff base copper alanine complex with green synthesized reduced graphene oxide for highly selective electrochemical detection of nitrite

A novel and selective nitrite sensor based on non-covalent interaction of Schiff base copper complex [Cu(sal-ala)(phen)] with reduced graphene oxide (RGO) was developed by simple eco-friendly approach. The morphology of the prepared RGO/[Cu(sal-ala)(phen)] nanocomposite was characterized by scanning electron microscopy (SEM), ultraviolet visible spectroscopy (UV), electrochemical impedance spectroscopy (EIS), energy dispersive X-ray spectroscopy, X-ray diffraction studies and Fourier transform infrared spectroscopy (FT-IR). On the other hand, the electrochemical studies of the prepared nanocomposite was investigated by cyclic voltammetry (CV) and amperometric technique. The RGO/[Cu(sal-ala)(phen)] nanocomposite modified glassy carbon electrode (GCE) exhibit the higher electrocatalytic activity towards detection of nitrite. Moreover, the RGO/[Cu(sal-ala)(phen)] modified GCE was determined the nitrite with low detection limit (19 nM), broad linear range (0.05–1000 μM) and high sensitivity (3.86 μA μM−1 cm−2). Besides, the proposed sensor shows good selectivity, repeatability, reproducibility and long term operational stability. The appreciable recoveries was achieved for the detection of nitrite in water and sausage samples, which imply the practical feasibility of the modified electrode.

Reduced graphene oxide/gold tetraphenyl porphyrin (RGO/Au–TPP) nanocomposite as an ultrasensitive amperometric sensor for environmentally toxic hydrazine

A gold tetra phenyl porphyrin/reduced graphene oxide (RGO/Au–TPP) nanocomposite film modified glassy carbon electrode (GCE) was prepared for the trace level detection of hydrazine. The prepared nanocomposite was characterized by scanning electron microscopy, X-ray diffraction studies, transmission electron microscopy, ultraviolet-visible spectroscopy, infrared spectroscopy and Raman spectroscopy. Electrochemical studies of the modified electrode were carried out by the cyclic voltammetry and an amperometric (i–t) method. The RGO/Au–TPP/GCE exhibited enhanced electrocatalytic activity towards the detection of hydrazine. The detection limit was 3 nM, the linear range was between 20 nM to 198 μM L−1, and the sensitivity was 2.266 μA μM−1 cm−2. The modified electrode also selectively detected hydrazine in the presence of 500 fold excess concentrations of other interfering ions. The practical applicability of the sensor was addressed in different water samples which showed satisfactory recoveries. Moreover, the sensor showed acceptable repeatability, reproducibility and higher stability.

Electrochemical co-preparation of cobalt sulfide/reduced graphene oxide composite for electrocatalytic activity and determination of H2O2 in biological samples

In this work, we describe a simple approach for the preparation of cobalt sulfide/reduced graphene oxide (CoS/RGO) nanohybrids via single step electrochemical method. The electrocatalytic activity of the CoS/RGO nanohybrids was evaluated towards the detection hydrogen peroxide (H2O2). The physiochemical properties of the prepared composite was characterized by means of field emission scanning electron microscopy, high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, Raman spectroscopy and X-ray powder diffraction patterns. The CoS/RGO modified electrode showed superior electrocatalytic activity towards the detection of H2O2. The amperometric (i-t) studies revealed that the CoS/RGO performed well by attaining a wide linear response range of H2O2 from 0.1 to 2542.4μM with a lower detection limit 42nM and the sensitivity of 2.519μAμM-1cm-2. Meanwhile, the CoS/RGO nanohybrids exhibited good selectivity, rapid and stable response towards H2O2. The practical applicability of the sensor was successfully evaluated in human serum and urine samples with satisfactory recoveries.

“Design of novel WO3/CB nanohybrids” An affordable and efficient electrochemical sensor for the detection of multifunctional flavonoid rutin

The multifunctional properties of rutin have been utilized in the preparation of various pharmaceutical products. As a result, rutin is considered to be one of the most consumed flavonoid substances in pharmaceutical applications. Hence, researchers have been devoted to developing a simple, cheap and highly efficient electrochemical sensor for the detection of rutin. Nowadays, inorganic nanomaterials, especially metal oxides, with distinct structures and properties are being used for the development of various kinds of electrochemical sensors. The wide band gap values of WO3 make it a potentially important sensing material. Therefore, we have synthesized novel CB/WO3 nanohybrids using a single step hydrothermal technique and applied them for the electrochemical detection of rutin. In this work, we have chosen the inexpensive and superconductive CB for the synthesis of the nanohybrids, which is an alternative to other carbonaceous materials. The structural, morphological and compositional properties of the synthesized material were systematically characterized by various suitable spectrophotometric techniques. Moreover, the as-prepared electrode materials exhibited a good electrochemical performance towards the electro-oxidation of rutin. Fascinatingly, the lowest LOD of about 2 nM with appreciable linearity from 0.01 to 75.46 μM was obtained for the electrochemical determination of rutin. Furthermore, the practical feasibility of the proposed sensor was investigated using commercially available rutin-containing tablets.

Innovative Strategy Based on a Novel Carbon-Black−β-Cyclodextrin Nanocomposite for the Simultaneous Determination of the Anticancer Drug Flutamide and the Environmental Pollutant 4-Nitrophenol

In the present work, a noncovalent and eco-friendly approach was proposed to prepare a carbon-black/β-cyclodextrin (CB/β-CD) nanocomposite. CB/β-CD-nanocomposite-modified screen-printed carbon electrodes were applied for the simultaneous determination of the anticancer drug flutamide (Flut) and the environmental pollutant 4-nitrophenol (4-NP). The electrochemical performance of the proposed sensor relied on the conductivity of CB, the different binding strengths of the guests (Flut and 4-NP) to the host (β-CD), and the different reduction potentials of the nitroaromatic compounds. Fascinatingly, the proposed sensor exhibited an excellent electrochemical performance with high sensitivity, selectivity, and reproducibility. The obtained wide linear ranges were 0.05-158.3 and 0.125-225.8 μM for Flut and 4-NP. The low detection limits of 0.016 and 0.040 μM with the higher sensitivities of 5.476 and 9.168 μA μM-1 cm-2 were achieved for the determination of Flut and 4-NP, respectively. The practical feasibility of the proposed sensor was studied in tap-water and human-serum samples.