Hydrothermally synthesized cubical zinc manganite nanostructure for electrocatalytic detection of sulfadiazine

Optical, thermal, mechanical, and antibacterial properties of polyvinyl alcohol/sodium alginate/ZnMn2O4 nanocomposites films for various optical devices and food packaging applications

This work involves preparing zinc manganite nanoparticles (ZnMn2O4 NPs) using the Sol-gel method. Polymer nanocomposites of polyvinyl alcohol (PVA)/Sodium alginate (NaAlg)- ZnMn2O4 NPs were created using the solution casting technique. The polymer nanocomposites films were made with varying weight percentages of ZnMn2O4 nanoparticles. With the addition of nanofiller, the reduced direct and indirect energy band gap values and increased Urbach energy values were discovered in the UV-Vis data. XRD data showed a reduction in crystallinity degree with dopant. ZnMn2O4 NPs had a strong interaction with PVA/NaAlg blend, as confirmed by FTIR. The addition of ZnMn2O4 NPs led to improved thermal stability of the polymer nanocomposites films. Additionally, the nanocomposites films' mechanical characteristics were examined. The loading of ZnMn2O4 nanoparticles has been associated with an increasing trend in the mechanical properties of the nanocomposites, including its toughness, Young's modulus, Tensile strength (Ts), and elongation. The antibacterial activity of the nanocomposites against fungus and bacteria was studied. Additionally, PVA/NaAlg-ZnMn2O4 nanocomposites films had good antibacterial characteristics against environmental microorganisms such as Gram-positive (G+) S. aureus and Gram-negative(G-) E. coli bacteria as well as fungi C. albicans and A. niger. It was observed that the biodegradability of the nanocomposite films was lower compared to the pure PVA/NaAlg film. Compared to pure film, the water solubility was decreased upon the addition of ZnMn2O4 NPs. After ZnMn2O4 was added to the pure blend, the WVTR decreased. The produced polymer nanocomposites films appear to be a promising material for food packing, according to these results.

Electrochemical Sensors Based on Transition Metal Materials for Phenolic Compound Detection

Electrochemical sensors have been recognized as crucial tools for monitoring comprehensive chemical information, especially in the detection of a significant class of molecules known as phenolic compounds. These compounds can be present in water as hazardous analytes and trace contaminants, as well as in living organisms where they regulate their metabolism. The sensitive detection of phenolic compounds requires highly efficient and cost-effective electrocatalysts to enable the development of high-performance sensors. Therefore, this review focuses on the development of advanced materials with excellent catalytic activity as alternative electrocatalysts to conventional ones, with a specific emphasis on transition metal-based electrocatalysts for the detection of phenolic compounds. This research is particularly relevant in diverse sectors such as water quality, food safety, and healthcare.

Highly dispersed redox antimony oxide pairs for accurate detection and electrochemistry-controlled recovery toward an antibiotic drug: Sulfadiazine

BACKGROUND

Sulfadiazine (SDZ) is a broad-spectrum antibiotic widely used in aquaculture and animal husbandry and it is easy to remain in the water system to damage the human body. Therefore, detection and removal of sulfadiazine in water systems become critical. Nowadays, catalysts and visible light are used to degrade sulfadiazine into smaller molecules containing N and S to reduce toxicity. However, these small molecules are easily released into water and the atmosphere to be the acid rain. Therefore, it is urgent to design a sensor with the ability to detect and remove SDZ at the same time. (96) RESULTS: We designed a novel composite catalyst sensor (Sb6O13@LTA GCE) with the ability to simultaneously monitor and remove sulfadiazine. The catalyst is generated by introducing SbCl5 into the reactive gel of LTA (Linde Type A) structure zeolite. In the hydrothermal reaction, the corrosive SbCl5 is transferred into nanosized Sb6O13 nanoparticle which is highly dispersed in the opening nano-scaled windows of the zeolite through redox and self-assembled progress. In the selected electrochemical overpotential range, the Sb6O13@LTA composited modified electrode could complete adsorption and desorption of SDZ through the electron transfer from Sb3+ to Sb5+. As the catalyst is in high stability, the only loss in the whole process of recovering SDZ is a small amount of electric energy. The extra-low detection limit and the removal efficiency of Sb6O13@LTA GCE have been achieved 4.0 pM and 19.3 mg/20 mg (136) SIGNIFICANCE: The prepared novel sensor has low detection limit, high removal efficiency and high selectivity for sulfadiazine. The Sb6O13@LTA GCE sensor, which is low-cost and has a simple preparation method, exhibits good reproducibility in both seawater and cell fluid. This provides the possibility for wide application in detecting and removing SDZ in water system. (53).

Coral-like, self-assembled, and spatially bounded Ag nano-particles on franzinite zeolite composite sensor toward accurate, synergetic, and ultra-trace sulfadiazine detection

A coral-like Ag@FRA zeolite nanocomposite sensor reveals high sensitivity toward sulfadiazine (SDZ) in a dual detection of fluorescence and electrochemistry. The sensor has been as-synthesized in the hydrothermal condition through a one-pot self-assembly process in which the high crystalline Ag nanoparticles (NPs) are closely arranged and stacked on the nanosized surface cage window of the FRA (Franzinite) zeolite. Strong ultrasound can drive the coral-like composite release Ag nanoparticles whose distribution range mainly from 10 to 12 nm lead to the purple fluorescence in an emission spectrum. In sea water, the fluorescence increases linearly in the SDZ concentration range of 5 × 10-18-5 × 10-10 M. Furthermore, the LOD (limit of detection) reaches 1.4 × 10-22 M by the spatial confinement effect of the coral-liked FRA cage structure in CV (cyclic voltammetry) method at the characteristic potential peak position of 0.1 V vs. SCE. The theoretical calculation also confirms that the FRA cage structure matches well with the SDZ molecules. Further studies indicate the generation of a novel stable composite sensor with high specificity, good recovery and repeatability, which depends on the induction of silver ions upon the artificial synthesis of FRA.

An Electrochemical Sensor for Sulfadiazine Determination Based on a Copper Nanoparticles/Molecularly Imprinted Overoxidized Polypyrrole Composite

To protect consumers from risks related to overexposure to sulfadiazine, total residues of this antibacterial agent in animal-origin foodstuffs not exceed international regulations. To this end, a new electrochemical sensor based on a molecularly imprinted polymer nanocomposite using overoxidized polypyrrole and copper nanoparticles for the detection of sulfadiazine is elaborated. After optimization of the preparation of the electrochemical sensors, their differential pulse voltammetric signal exhibits an excellent stability and reproducibility at 1.05 V, with a large linear range between 10^-9 and 10^-5 mol L^-1 and a low detection limit of 3.1 × 10^-10 mol L^-1. The produced sulfadiazine sensor was successfully tested in real milk samples. The combination of the properties of the electrical conduction of copper nanoparticles with the properties of the preconcentration of the molecularly imprinted overoxidized polypyrrole allows for the highly sensitive detection of sulfadiazine, even in real milk samples. This strategy is new and leads to the lowest detection limit yet achieved, compared to those of the previously published sulfadiazine electrochemical sensors.

Theoretical Sensing Performance for Detection of Cyclophosphamide Drug by Using Aluminum Carbide (C3Al) Monolayer: a DFT Study

Because nanomaterials are highly reactive and electronically sensitive towards a variety of drug molecules, they are thought of as efficient drug sensors. In the present research study, an aluminum carbide (C₃Al) monolayer is employed and its interaction is examined with cyclophosphamide (CP) by performing DFT computations. The C₃Al monolayer is highly reactive and sensitive towards CP according to the computations. CP interacts with the C₃Al monolayer with the adsorption energy of -31.39 kcal/mol. A considerable charge transfer (CT) indicates an enhancement in the conductivity. Also, the charge density is explained based on the electron density differences (EDD). The decrease in CP/C₃Al energy gap (E_g) by approximately 52.91% is due to the remarkable effect of adsorption on the LUMO and the HOMO levels. Therefore, due to the decrease in E_g which can generate an electrical signal, the electrical conductivity is considerably increased. These results suggest that the C₃Al monolayer can be employed as a proper electronic drug sensor for CP. Also, the recovery time for the desorption process of CP form the surface of C₃Al is 351 s at 598 K.

An optical and electrochemical sensor based on L-arginine functionalized reduced graphene oxide

The electrochemical and photochemical properties of graphene derivatives could be significantly improved by modifications in the chemical structure. Herein, reduced graphene oxide (RGO) was functionalized with L-arginine (L-Arg) by an amidation reaction between the support and amino acid. Deposition of a powerful ligand, L-Arg, on the optically active support generated an effective optical chemosensor for the determination of Cd(II), Co(II), Pb(II), and Cu(II). In addition, L-Arg-RGO was used as an electrode modifier to fabricate L-Arg-RGO modified glassy-carbon electrode (L-Arg-RGO/GCE) to be employed in the selective detection of Pb(II) ions by differential pulse anodic stripping voltammetry (DP-ASV). L-Arg-RGO/GCE afforded better results than the bare GCE, RGO/GCE, and L-Arg functionalized graphene quantum dot modified GCE. The nanostructure of RGO, modification by L-Arg, and homogeneous immobilization of resultant nanoparticles at the electrode surface are the reasons for outstanding results. The proposed electrochemical sensor has a wide linear range with a limit of detection equal to 0.06 nM, leading to the easy detection of Pb(II) in the presence of other cations. This research highlighted that RGO as a promising support of optical, and electrochemical sensors could be used in the selective, and sensitive determination of transition metals depends on the nature of the modifier. Moreover, L-Arg as an abundant amino acid deserves to perch on the support for optical, and electrochemical determination of transition metals.

Hydrothermally constructed AgWO4-rGO nanocomposites as an electrode enhancer for ultrasensitive electrochemical detection of hazardous herbicide crisquat

The advancements in electrode materials with high efficiency has been prioritized to effectively monitor the presence of harmful pesticides concerning the environment. In such a way, we hydrothermally constructed a hybrid AgWO₄-rGO nanocomposites for the rapid electrochemical detection of crisquat (CQT). The structural, compositional, morphological and topographical characterization for AgWO₄-rGO nanocomposites is thoroughly performed to understand its electrocatalytic properties. The AgWO₄-rGO nanocomposites are used as an electrode enhancer (rGO@AgWO₄/GCE) for the electrochemical investigations towards CQT detection. The results indicated that the rGO@AgWO₄/GCE possessed an excellent catalytic activity with a wide linear detection range 1-1108 μM coupled with an ultrasensitive limit of detection (LOD) 0.0661 μM for electrochemical CQT detection. The rGO@AgWO₄/GCE CQT sensor also expressed remarkable sensitivity of 0.6306 μAμM^-1cm^-2 in addition to good selectivity and reproducibility. Furthermore, the commercial CQT, river water, tap water and washed vegetable water are used as a representative for real world analysis using rGO@AgWO₄/GCE and results are highly appreciable for the real time CQT detection. Our work proposes a novel hybrid rGO@AgWO₄ nanocomposites reinforced electrodes for ultra-trace level CQT detection with good reliability and can be advocated for real time detection of pesticides.

Modification of glassy carbon electrode with manganese cobalt oxide-cubic like structures incorporated graphitic carbon nitride sheets for the voltammetric determination of 2,4,6 -trichlorophenol

Novel cube-like transition metal oxide embedded on graphitic carbon nitride (MCO@GCN) formed a hybrid composite via hydrothermal assisted sonochemical synthesis. The synthesized composite was examined with various physical characterizations such as morphological SEM, EDX, XRD, and FT-IR spectroscopy. The electrocatalytic activity of MCO@GCN composite was further investigated when used  to modify a glassy carbon electrode (GCE). The electrochemical sensor was investigated using modified MCO@GCN/GCE towards environmental pollutant 2,4,6-trichlorophenol (2,4,6-TCP) detection with at a potential of (+ 0.654 V vs Ag/AgCl) in pH-7. The structural features have favored a high charge transfer ratio with excellent conductivity which showed a low detection limit (LOD) of 0.0068 μM and sensitivity of 23.57 μA·μM^-1·cm^-2 comprising a wide linear working range of 0.01-1720 μM by using differential pulse voltammetry. Besides, the MCO@GCN/GCE displayed excellent selectivity , repeatability, reproducibility, storage, and operational stability. Notably, the proposed MCO@GCN/GCE was validated with different environmental samples (tap, river, and industrial water) with RSD 0.62-2.86% and 96.51-99.66% (n = 3) recovery.

A disposable electrode modified with metal orthovanadate and sulfur-reduced graphene oxide for electrochemical detection of

CVO@SRG composite was prepared by a hydrothermal method and the voltammetric measurement of an organic compound.