Thangavelu Kokulnathan

One-step sonochemical synthesis of 1D β-stannous tungstate nanorods: An efficient and excellent electrocatalyst for the selective electrochemical detection of antipsychotic drug chlorpromazine

In the modern world, the contamination of ecosystem by human and veterinary pharmaceutical drugs through the metabolic excretion, improper disposal/industrial waste has been subjected to a hot issue. Therefore, exploitation of exclusive structured material and reliable technique is a necessary task to the precise detection of drugs. With this regards, we made an effort for the fabrication of novel one-dimensional (1D) stannous tungstate nanorods (β-SnW NRs) via simple sonochemical approach and used as an electrochemical sensor for the detection of antipsychotic drug chlorpromazine (CPZ) for the first time. The crystallographic structure, surface topology, elemental compositions and their distributions and ionic states were enquired by different spectroscopic techniques such as XRD, FTIR, SEM, EDS, elemental mapping and XPS analysis. The developed β-SnW NRs/GCE sensor exhibits a rapid and sensitive electrochemical response towards CPZ sensing with wide linear response range (0.01-457 µM), high sensitivity (2.487 µA µM-1 cm-2), low detection limit (0.003 µM) and excellent selectivity. Besides, the as-proposed electrochemical sensor was successfully applied to real sample analysis in commercial CPZ drug and biological fluids and the acquired recovery results are quite satisfactory. The proposed sonochemical method for the preparation of β-SnW NRs is low cost, very simple, fast and efficient for sensor applications.

Enhanced photocatalytic degradation of atrazine by platinized titanium dioxide under 352 nm irradiation

Simply coating 1 wt.% of platinum on titanium dioxide (TiO2) surface resulted in simple preparation of platinized TiO2 (Pt-TiO2). This study demonstrated the photodegradation of atrazine (ATZ) using either Pt-TiO2 or TiO2 as a photocatalyst under 352 nm light irradiation. The Pt-TiO2-catalyzed ATZ degradation reached 76% in 3 hours without adding H2O2 solution or aeration, which was more than 10% higher than the TiO2-catalyzed reaction. The decomposition product of Pt-TiO2-catalyzed ATZ degradation was mainly cyanuric acid. Thus, Pt-TiO2 as an effective photocatalyst has three main advantages in the photodegradation of ATZ under 352 nm irradiation. First, the coated Pt can facilitate the generation of appropriate amounts of OH radicals, so it can prevent the formation of over-oxidized TiO2. Second, aeration was not needed. Third, the excited electrons were mainly uni-directionally transferred to the catalyst surface to avoid recombination of electron-hole pairs.

Synthesis and application of bismuth ferrite nanosheets supported functionalized carbon nanofiber for enhanced electrochemical detection of toxic organic compound in water samples

Recently, the multiferroic material has fabulous attention in numerous applications owing to its excellent electronic conductivity, unique mechanical property, and higher electrocatalytic activity, etc. In this paper, we reported that the synthesis of bismuth ferrite (BiFeO3) nanosheets integrated functionalized carbon nanofiber (BiFeO3 NS/F-CNF) nanocomposite using a simple hydrothermal technique. Herein, the structural changes and crystalline property of prepared BiFeO3 NS/F-CNF nanocomposite were characterized using Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). From this detailed structural evolution, the formation of nanosheets like BiFeO3 and its nanocomposite with F-CNF were scrutinized and reported. Furthermore, the as-prepared BiFeO3 NS/F-CNF nanocomposite modified glassy carbon electrode (GCE) was applied for electrochemical detection of catechol (CC). As expected, BiFeO3 NS/F-CNF/GCE shows excellent electrocatalytic activity as well as 3.44 (F-CNF/GCE) and 7.92 (BiFeO3 NS/GCE) fold higher electrochemical redox response for CC sensing. Moreover, the proposed sensor displays a wide linear range from 0.003 to 78.02 µM with a very low detection limit of 0.0015 µM. In addition, we have validated the real-time application of our developed CC sensor in different water samples.

Highly selective electrochemical detection of antipsychotic drug chlorpromazine in drug and human urine samples based on peas-like strontium molybdate as an electrocatalyst

The countless use of antibiotics in veterinary and human medicine causes severe health risks to both humans and animals. In this context, monitoring of the antibiotic drug in the veterinary and human pathological system is important and provokes a universal challenge. Therefore, development of simple and sensitive inorganic materials with unique morphology is of great importance for the trace level monitoring of pharmaceutical content in the environment. Herein, we developed a novel peas-like strontium molybdate catalyst (SrMoO4; SrM) synthesized by a simple sonochemical approach and utilized as an electrochemical sensor for the detection of antipsychotic drug chlorpromazine (CPZ). The crystalline structure, surface morphology, elemental compositions and textural properties were systematically investigated by various analytical and spectroscopic techniques. As an electrochemical sensor, inorganic binary SrM modified screen printed carbon electrode (SrM/SPCE) exhibited an enhanced electrocatalytic activity towards CPZ sensing with excellent analytical performance such as wide linear response ranges and lowest detection limit of 0.1–143 and 153–1683 μM and 0.028 μM respectively. Moreover, the as-prepared SrM/SPCE showed an excellent selectivity even in the existence of co-interfering drugs, biological compounds and common metal ions. In addition, the SrM/SPCE applied to the real samples analysis in commercially available CPZ drug and human urine samples and the observed recoveries are quite satisfactory.

Hexammine cobalt(III) coordination complex grafted reduced graphene oxide composite for sensitive and selective electrochemical determination of morin in fruit samples

In this report, we have successfully prepared the hexammine cobalt(III) coordination complex [Co(NH3)6]3+ grafted onto a reduced graphene oxide (RGO) composite modified glassy carbon electrode (GCE) for the electrochemical determination of morin (MR). The RGO/[Co(NH3)6]3+ composite was prepared by a simple sonochemical technique. The as-prepared inorganic complex was characterized using suitable physical and chemical characterization techniques. The as-prepared composite was characterized by scanning electron microscopy, elemental mapping analysis and X-ray diffraction studies. In addition, the electrochemical performance of the fabricated electrode was assessed by the cyclic voltammetry, differential pulse voltammetry and electrochemical impedance spectroscopy studies. Besides, the RGO/[Co(NH3)6]3+ modified electrode had notable electrocatalytic activity towards the detection of MR. Under the optimized condition, the modified electrode showed excellent linearity ranges, acceptable limit of detection, and high sensitivity of 0.008–72.35 μM, 1.0 nM and 4.326 μA μM−1 cm−2, respectively. The fabricated electrode exhibited acceptable repeatability, reproducibility and stability. On the other hand, the proposed RGO/[Co(NH3)6]3+ modified electrodes have been applied for the detection of MR in fruit samples, and the results reveal adequate recovery.

Ecofriendly preparation of graphene sheets decorated with an ethylenediamine copper(II) complex composite modified electrode for the selective detection of hydroquinone in water

In the present work, we have prepared an ecofriendly reduced graphene oxide decorated copper(II) ethylenediamine complex ([Cu(en)2]2+) (en = ethylenediamine) modified glassy carbon electrode (GCE) for the electrochemical detection of hydroquinone (HQ). The as-prepared composite was characterized by SEM, EDX, XRD, UV and FT-IR. Moreover, the electrochemical behaviour of the modified electrode was investigated by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and differential pulse voltammetry (DPV). In addition, the GCE/RGO/[Cu(en)2]2+ modified electrode has excellent electrocatalytic activity towards the detection of HQ. Under the optimized conditions, the proposed sensor exhibited a wide linear detection response range of 0.1 μM–104 μM with a limit of detection of 0.025 μM and a sensitivity of 5.0763 μA μM−1 cm−2. Furthermore, the fabricated electrode exhibited acceptable reproducibility, repeatability and stability. On the other hand, the GCE/RGO/[Cu(en)2]2+ modified electrodes have been applied for the real sample analysis in environmental water samples, which exhibit acceptable recovery. Hence, it is suggested that the GCE/RGO/[Cu(en)2]2+ modified electrode is a potential electrode material that can be used for the detection of HQ in different real samples.

Novel electrochemical synthesis of copper oxide nanoparticles decorated graphene-β-cyclodextrin composite for trace-level detection of antibiotic drug metronidazole

Over the past decades, the synthesis of inorganic and organic nanocomposites has received much attention in the range of fields including electroanalysis of organic chemicals. In this regard, we have prepared copper oxide nanoparticle (CuO NPs) decorated graphene/β-cyclodextrin (GR-β-CD) composites using a simple electrochemical methodology, where the CuO NPs are electrodeposited on GR-β-CD composite modified electrodes. A stable GR-β-CD composite was prepared by sonication of GR in β-CD aqueous solution. As-prepared GR-β-CD/CuO NPs composites were characterized by the high-resolution scanning electron microscopy, X-ray diffraction, and Raman spectroscopy. Cyclic voltammetry results reveal that the GR-β-CD/CuO NPs composite modified electrode exhibits an excellent catalytic activity and lower reduction potential towards the electrochemical detection of metronidazole (MTZ) over other modified electrodes including GR, GR-β-CD, and CuO NPs. Under optimized conditions, amperometry was used for the determination of MTZ using GR-β-CD/CuO NPs composite modified electrodes. The response of MTZ using the composite electrodes was linear over the range from 0.002 to 210.0 µM. This sensor showed the lowest limit of detection of 0.6 nM and was much lower than the previously reported MTZ sensors. In addition, the sensor is highly sensitive, selective and durable in the presence of a range of potentially interfering electroactive compounds.