Microwave Assisted Synthesis,Spectrofluorometric Characterization of Azomethine as Intermediate for Transition Metal Complexes with Biological Application

Azomethine (1, 5 - Dimethyl - 2 - phenyl -[(3, 4, 5 -trimethoxybenzylidene) amino] -1, 2 - dihydropyrazol - 3 - one) (DTAD) was synthesized by the reaction of 4-aminophenazone with 3,4,5 trimrthoxybenzaldehyd by microwave irradiation. Physicochemical studies such as electronic absorption, molar absorptivity, oscillator strength, dipole moment, florescent quantum yield were investigated in order to explore the analytical potential of azomethine dye. Azomethine go through the solubilization in different micelles and may be used as a probe or quencher to determine the critical micelle concentration (CMC) of SDS and CTAB. It’s coordinate to metal salt through the pyrazol-3-one oxygen and the azomethine nitrogen. The structure of ligand and its meal complexes was elucidated by IR, ¹H, ¹³C-NMR, EI-MS spectroscopic methods and elemental analysis. The antibacterial activity of these compounds were first tested in vitro by the disc diffusion assay against two Gram-positive and two Gram-negative bacteria, and then the minimum inhibitory concentration was using chloramphenicol as reference drug. The results showed that compound 1.1 is better inhibitor of both types of tested bacteria as compared to chloramphenicol.     

Sensitive L-leucine sensor based on a glassy carbon electrode modified with SrO nanorods

Microchimica Acta - Strontium oxide nanorods (SrO NR) were prepared in alkaline medium by a wet-chemical method. They were characterized by FTIR, UV/Vis, field emission scanning electron...     

Energy-Saving Electrolytic Hydrogen Generation: Ni2P Nanoarray as a High-Performance Non-Noble-Metal Electrocatalyst

It is highly attractive but challenging to develop earth-abundant electrocatalysts for energy-saving electrolytic hydrogen generation. Herein, we report that Ni₂P nanoarrays grown in situ on nickel foam (Ni₂P/NF) behave as a durable high-performance non-noble-metal electrocatalyst for hydrazine oxidation reaction (HzOR) in alkaline media. The replacement of the sluggish anodic oxygen evolution reaction with such the more thermodynamically favorable HzOR enables energy-saving electrochemical hydrogen production with the use of Ni₂P/NF as a bifunctional catalyst for anodic HzOR and cathodic hydrogen evolution reaction. When operated at room temperature, this two-electrode electrolytic system drives 500 mA cm⁻² at a cell voltage as low as 1.0 V with strong long-term electrochemical durability and 100 % Faradaic efficiency for hydrogen evolution in 1.0 m KOH aqueous solution with 0.5 m hydrazine.     

Hydrazine sensor based on silver nanoparticle-decorated polyaniline tungstophosphate nanocomposite for use in environmental remediation

Microchimica Acta - A nanocomposite consisting of silver nanoparticle-decorated polyaniline and tungstophosphate was deposited on a glassy carbon electrode to result in an improved electrochemical...     

Selective Hg2+ sensor performance based various carbon‐nanofillers into CuO‐PMMA nanocomposites

Ternary nanocomposites (NCs) containing copper oxide (CuO)/poly(methyl methacrylate)/various carbon‐based nanofillers have been successfully prepared as thin films by an ex situ method as a selective Hg⁺² sensor. The structural, morphological, and electrochemical properties of the NCs were identified by all common characterization tools. The FT‐IR curves of these NCs proved the efficiency of CuO mixed with single‐walled CNTs (CuO/SWCNTs), multi‐walled CNTs (CuO/MWCNTs), or graphene (CuO/G) nanoparticles in the PMMA polymer matrix. The mixed nanofillers significantly improved the properties of the PMMA film. The thermal characteristics of the pure PMMA polymer matrix were highly developed by adding nanofillers in the form of NCs. The maximum composite degradation temperature (CDT_max) values were comparable for all the NCs and were in the range of 345 to 406°C. For fabrication, the CuO‐PMMA‐SWCNT, CuO‐PMMA‐MWCNT, and CuO‐PMMA‐GNCs were coated onto a glassy carbon electrode (GCE) to form a tiny layer with orderly thickness using a conductive 5% Nafion chemical binder. During the electrochemical investigation, it was found that CuO‐PMMA‐SWCNT had the maximum response toward Hg²⁺ ions compared to the other nanofillers in a buffer medium (phosphate type). To calibrate the Hg²⁺ ionic sensor, the data were plotted against Hg²⁺ ion concentration and the proposed sensor showed linearity over a wide range of concentrations (0.1‐0.01 mM), which is called the linear dynamic range (LDR). The analytical parameters, such as sensitivity (1.70 × 102 μAμM^‐1 cm^?2), detection limit (55.76 ± 2.79 pM), and limit of quantification (185.87 pM) were calculated from the calibration curve. Moreover, it showed good reproducibility, fast response time, good linearity, large LDR, and good stability. The CuO‐PMMA‐SWCNT NC‐modified GCE offers a new route to fabricate novel heavy metal ionic sensors, which might be used in green environment and health development applications.     

A glutathione biosensor based on a glassy carbon electrode modified with CdO nanoparticle-decorated carbon nanotubes in a nafion matrix

A nanocomposite consisting of cadmium oxide decorated with carbon nanotubes (CdO.CNT NC) was prepared by a wet-chemical technique, and its optical, morphological, and structural properties were characterized by FTIR, UV/Vis, FESEM coupled to XEDS, XPS, and XRD methods. A flat glassy carbon electrode was modified with the nanocomposite to obtain a sensor for L-glutathione (GSH) which displays improved sensitivity, a large dynamic range and good long-term stability. The calibration plot (best acquired at a voltage of 0.5 V) is linear (r ² = 0.99) in the 0.1 nM to 0.01 M GSH concentration range. The detection limit is as low as 30.0 pM, and the sensitivity is ~9.49 μA?μM^?1?cm^?2. To the best of our knowledge, this is the first report on the determination of GSH using such a modified glassy carbon electrode (GCE) in combination with I-V method. The GCE was applied to the selective determination of GSH in spiked rabbit serum samples and gave acceptable results.

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Graphical abstract A selective glutathione biosensor based on wet-chemically prepared CdO.CNT/Nafion/GCE was fabricated by reliable I-V method and shows good analytical parameters such as high sensitivity, low detection limit, long-term stability, and large dynamic range.

     

Assessment of Melamine in Different Water Samples with ZnO-doped Co3O4 Nanoparticles on a Glassy Carbon Electrode by Differential Pulse Voltammetry

In this investigation, a melamine electrochemical sensor has been developed by using wet-chemically synthesized low-dimensional aggregated nanoparticles (NPs) of ZnO-doped Co₃O₄ as sensing substrate that were decorated onto flat glassy carbon electrode (GCE). The characterization of NPs such as UV-Vis, FTIR, XRD, XPS, EDS, and FESEM was done for detailed investigations in optical, functional, structural, elemental, and morphological analyses. The ZnO-doped Co₃O₄ NPs decorated GCE was used as a sensing probe to analyze the target chemical melamine in a phosphate buffer at pH 5.7 by applying differential pulse voltammetry (DPV). It exhibited good performances in terms of sensor analytical parameters such as large linear dynamic range (LDR; 0.15–1.35 mM) of melamine detection, high sensitivity (80.6 μA mM⁻¹ cm⁻²), low limit of detection (LOD; 0.118±0.005 mM), low limit of quantification (LOQ; 0.393 mM), and fast response time (30 s). Besides this, the good reproducibility (in several hours) and repeatability were investigated under identical conditions. Moreover, it was implemented to measure the long-time stability, electron mobility, less charge-transfer resistance, and analyzed diffusion-controlled process for the oxidation reaction of the NPs assembled working GCE electrode, which showed outstanding chemical sensor performances. For validation, real environmental samples were collected from various water sources and investigated successfully with regard to the reliability of the selective melamine detection with prepared NPs coated sensor probe. Therefore, this approach might be introduced as an alternative route in the sensor technology to detect selectively unsafe chemicals by an electrochemical method with nanostructure-doped materials for the safety of environmental, ecological, healthcare fields in a broad scale.     

Genotoxic and Cytotoxic Properties of Zinc Oxide Nanoparticles Phyto-Fabricated from the Obscure Morning Glory Plant Ipomoea obscura (L.) Ker Gawl

The study was undertaken to investigate the antioxidant, genotoxic, and cytotoxic potentialities of phyto-fabricated zinc oxide nanoparticles (ZnO-NPs) from Ipomoea obscura (L.) Ker Gawl. aqueous leaf extract. The UV-visible spectral analysis of the ZnO-NPs showed an absorption peak at 304 nm with a bandgap energy of 3.54 eV, which are characteristics of zinc nanoparticles. Moreover, the particles were of nano-size (~24.26 nm) with 88.11% purity and were agglomerated as observed through Scanning Electron Microscopy (SEM). The phyto-fabricated ZnO-NPs offered radical scavenging activity (RSA) in a dose-dependent manner with an IC₅₀ of 0.45 mg mL⁻¹. In addition, the genotoxicity studies of ZnO-NPs carried out on onion root tips revealed that the particles were able to significantly inhibit the cell division at the mitotic stage with a mitotic index of 39.49%. Further, the cytotoxic studies on HT-29 cells showed that the phyto-fabricated ZnO-NPs could arrest the cell division as early as in the G0/G1 phase (with 92.14%) with 73.14% cells showing early apoptotic symptoms after 24 h of incubation. The results of the study affirm the ability of phyto-fabricated ZnO-NPs from aqueous leaf extract of I. obscura is beneficial in the cytotoxic application.