Novel Dithiocarbamates for electrochemical detection of Nickel (II) in environmental samples

Ammonium 4-phenylpiperazine-1-dithiocarbamate (Amm 4-PP-DTC) and ammonium 4-benzylpiperidine-1-dithiocarbamate (Amm 4-BP-DTC) were synthesized for the determination of nickel(II) using catalytic hydrogen currents (CHC’s) technique with DC Polarography. The method was based on the chelation of nickel(II) with Amm 4-PP-DTC/ Amm 4-BP-DTC in presence of NH 4 OH at pH 6.8 to produce catalytic hydrogen current at -1.50V and -1.41 V vs. SCE respectively. Optimized polarographic conditions were established by studying effect of pH, supporting electrolyte (NH4Cl), ligands and metal ion concentration and effect of adverse ions on peak height to improve the sensitivity, selectivity and detection limits of the present method. This technique is successfully applied for the analysis of nickel(II) in different matrices with recoveries ranging from 96.0-99.0 % and the results obtained were comparable with the atomic absorption spectroscopy

Insight into the biosensing of graphene

Graphene oxide, a century old material has attracted the interest of researchers owing to its specific 2D structure and unique electronic, optical, thermal, mechanical and electrochemical properties. The recent advancements in the field of biotechnology and biomedical engineering are targeted at exploring the biosensing applications of graphene oxide due to its biocompatibility. It is considered to be one of the most versatile materials, with wide range of applications which can be tailored by functionalization of the different oxygen containing groups present in the structure. In this review the focus is on the biosensing applications of graphene oxide, detection of analytes with high sensitivity and selectivity. This would give insight into the designing of feasible protocols for the analysis of therapeutic diseases and environmental safety, thereby improving the quality of human life

Insights into the Design of An Enzyme Free Sustainable Sensing Platform for Efavirenz

In this study, a new hybrid sensor was developed using titanium oxide nanoparticles (TiO2-NPs) and nafion as an anchor agent on a glassy carbon electrode (GCE/TiO2-NPs-nafion) to detect efavirenz (EFV), an anti-HIV medication. TiO2-NPs was synthesized using Eucalyptus globulus leaf extract and characterized using ultraviolet–visible spectroscopy (UV–VIS), scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy-dispersive spectroscopy (EDS). The electrochemical and sensing properties of the developed sensor for EFV were assessed using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The current response of GCE/TiO2-NPs-nafion electrode towards the oxidation of EFV was greater compared to the bare GCE and GCE/TiO2-NPs electrodes. A linear dynamic range of 4.5 to 18.7 µM with 0.01 µM limit of detection was recorded on the electrode using differential pulse voltammetry (DPV). The electrochemical sensor demonstrated good selectivity and practicality for detecting EFV in pharmaceuticals (EFV drugs) with excellent recovery rates, ranging from 92.0–103.9%. The reactive sites of EFV have been analyzed using quantum chemical calculations based on density functional theory (DFT). Monte Carlo (MC) simulations revealed a strong electrostatic interaction on the substrate-adsorbate (GCE/TiO2-NPs-nafion-EFV) system. Results show good agreement between the MC computed adsorption energies and the experimental CV results for EFV. The stronger adsorption energy of nafion onto the GCE/TiO2-NPs substrate contributed to the catalytic role in the signal amplification for sensing of EFV. Our results provide an effective way to explore the design of new 2D materials for sensing of EFV, which is highly significant in medicinal and materials chemistry

Electrochemical non-enzymatic strategy with green synthesized Fe2O3CuO nanocomposite for detection of amiprofos-methyl herbicide in industrial effluents and soils

Iron oxide-Copper oxide nanoparticles composite (Fe2O3CuO NPs) was synthesized through a green phytosynthetic approach using Ocimum sanctum Linn (commonly known as Tulsi) leaf extract. The evaluation of electrocatalytic properties were evaluated by carrying out electrochemical detection of amiprofos-methyl (APM), an organophosphorus herbicide. It is moderately toxic to mammals and aquatic biodiversity and is considered to be an acetylcholinesterase inhibitor. The presence of specific natural phytochemicals such as eugenol, naringenin, apigenin, quercetin, and high amount of ascorbic acid in the aqueous extract of Ocimum sanctum Linn plant parts, has been widely used for the synthesis of various metallic nanoparticles where these compounds serve as reducing, stabilizing, and capping agents. The synthesized Fe2O3CuO NPs were characterized using scanning electron microscope (SEM), energy dispersive X-ray analysis (EDX), X-ray diffraction analysis (XRD), UV–Vis spectroscopy, Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). The modified electrode was electrochemically characterized by cyclic voltammetry and differential pulse voltammetry (DPV) techniques for the detection of APM. The electrochemical signals have increased by three folds in the detection of APM with Fe2O3CuO nanocomposite compared to the bare glassy carbon electrode. The electrochemical sensor showed a linear range of 0.05 to 30 µg/mL with a limit of detection of 0.0065 µg/mL. The developed electrochemical sensor was successfully applied for the detection of APM in different water and soil samples with recoveries ranging from 96.00−99.00%. The electrode showed good stability and reproducibility over a period of 10 days with a 95% of peak current than the former. The newly synthesized nanoparticles, thus, proved to be an interesting material for electrochemical and biological studies

Structural basis of pesticide detection by enzymatic biosensing: a molecular docking and MD simulation study

<p>Designing of rapid, facile, selective, and cost-effective biosensor technology is a growing area for the detection of various classes of pesticides. The biosensor with these features can be achieved only through the various bio-components using different transducers. This study, therefore, focuses on the usage of molecular docking, specificity tendencies, and capabilities of proteins for the detection of pesticides. Accordingly, the four transducers, acetylcholinesterase (ACH), cytochromes P450 (CYP), glutathione S-transferase (GST), and protein kinase C (PKC) were selected based on their applications including neurotransmitter, metabolism, detoxification enzyme, and protein phosphorylation. Then after molecular docking of the pesticides, fenobucarb, dichlorodiphenyltrichloroethane (DDT), and parathion onto each enzyme, the conformational behavior of the most stable complexes was further analyzed using 50 ns Molecular Dynamics (MD) simulations carried out under explicit water conditions. In the case of protein kinase C (PKC) and cytochrome P450 3A4 enzyme (CYP), the fenobucarb complex showed the most suitable combination of free energy of binding and inhibition constant −4.42 kcal/mol (573.73 μM) and −5.1 kcal/mol (183.49 μM), respectively. Parathion dominated for acetylcholinesterase (ACH) with −4.57 kcal/mol (448.09 μM) and lastly dichlorodiphenyltrichloroethane for glutathione S-transferase (GST), −5.43 kcal/mol (103.88 μM). The RMSD variations were critical for understanding the impact of pesticides as they distinctively influence the energetic attributes of the proteins. Overall, the outcomes from the extensive analysis provide an insight into the structural features of the proteins studied, thereby highlighting their potential use as a substrate in biorecognition sensing of pesticide compounds.</p

Biosynthesis of ZnFe2O4@Ag hybrid nanocomposites for degradation of 2,4-Dichlorophenoxyacetic acid herbicide

This work demonstrates recent advancements in the phytosynthetic and environmentally friendly method of preparing ZnFe2O4 and ZnFe2O4@Ag hybrid nanocomposites using Pedalium murex L leaf extract as a stabilizing and reducing agent. The synthesized nanocomposite was characterized with UV–vis, FTIR, TGA/DSC, XRD, FE-SEM, and EDX to investigate the electronic as well as morphological properties. Moreover, the photocatalytic behaviour of ZnFe2O4 and ZnFe2O4@Ag hybrid nanocomposites was evaluated with a breakdown of 2,4-dichlorophenoxyacetic acid (2,4-DPA) by exposing to UV–Vis light. The results obtained suggest that ZnFe2O4@Ag hybrid nanocomposite exhibited photocatalytic activity for the degradation of 2,4-DPA by approximately 94% in 60 min compared to ZnFe2O4. The hybrid nanostructure of ZnFe2O4@Ag significantly promoted charge transfer and prevented electron and hole recombination resulting in the enhancement of photocatalytic activity. Furthermore, ZnFe2O4@Ag nanocomposite showed the fair recyclable capacity for up to five catalytic cycles with an acceptable degradation percentage of 2,4-DPA. The findings of this study identify efficient charge transfer factor as a major contributor to the catalytic activity, with promising possibilities for the design of environmental remediation nanocomposite for harmful contaminants