Ultrasound-assisted synthesis of two-dimensional layered ytterbium substituted molybdenum diselenide nanosheets with excellent electrocatalytic activity for the electrochemical detection of diphenylamine anti-scald agent in fruit extract

Voltammetric nano-molar range quantification of agrochemical pesticide using needle-like strontium pyrophosphate embedded on sulfur doped graphitic carbon nitride electrocatalyst

The development of a viable sensor for agrochemical pesticides requires the assessment of trace levels. To achieve this, we developed a diphenylamine (DPA) sensor using needle-like strontium pyrophosphate embedded in sulfur-doped graphitic carbon nitride (SrPO/SCN). We obtained needle-like SrPO/SCN nanocomposite through co-precipitation followed by ultrasonication. The formation of the SrPO/SCN nanocomposite was verified through FT-IR, XRD, XPS, SEM-EDX, and HR-TEM analyses. Additionally, we explored their electrochemical behavior towards DPA using differential pulse voltammetry (DPV) and cyclic voltammetry (CV). The SrPO/SCN nanocomposite-modified electrode exhibited a higher anodic peak current (15.47 µA) than those of the other modified and unmodified electrodes. Under optimal experimental conditions, SrPO/SCN/GCE demonstrated a good limit of detection (0.009 µmol/L), dynamic linear range (0.05-98 µmol/L), and sensitivity (0.36 µAµM-1cm-2). Furthermore, the developed sensor exhibited excellent reproducibility, selectivity, and stability, and successfully detected DPA in real samples, including pear and apple samples, with good recoveries.

A disposable voltammetric sensor for the determination of diphenylamine using modified pencil graphite electrode

This study reports the electrochemical monitoring and sensing of diphenylamine (DPA), an anti-scald agent on a modified pencil graphite electrode (PGE). DPA is also a potentially toxic environmental pollutant. A polymer of tyrosine synthesized by electrochemical process was utilized for the determination of DPA in real samples. The electrodes were characterized using IR, SEM, EDAX, AFM and EIS analyses. As far as we know, this is first time reporting the utilization of modified PGE via green approach for the monitoring of DPA. A dynamic linear range of 1.00-117.11 µM with a lower detection limit (LOD) of 0.7050 µM was showed by this sensor for the electrochemical quantification of DPA. The electrochemical oxidation of DPA on the modified sensor followed a mixed adsorption -diffusion controlled kinetics. The sensor also showed good anti-interference property for the determination of DPA in real samples. Furthermore, the developed sensor was applied for the selective sensing of DPA from real apple extracts with good recovery. The real sample analysis was validated with standard spectrophotometric method.

La-doped NiWO4 coupled with reduced graphene oxide for effective electrochemical determination of diphenylamine

Diphenylamine (DPA) is a harmful pesticide widely used to control post-harvest scald of fruits. In this study, rapid and sensitive determination of DPA was realized by the development of an effective electrochemical sensor, which was fabricated by coupling La-doped NiWO4 nanoparticles (La/NiWO4) with reduced graphene oxide (rGO), and the obtained rGO/La/NiWO4 nanocomposite was modified on glassy carbon electrodes (GCEs). The morphologies, structures and compositions were well characterized, and the effects of La doping and the introduction of rGO on the crystal structure and electrochemical performance were discussed. The incorporation of both La and rGO was found to enhance the active surface area and improve conductivity, resulting in the enhanced electrocatalytic performance of rGO/La/NiWO4/GCE, including a wide linear range (0.01-500 μM), a low detection limit (0.0058 μM) and high sensitivity (1.778 μA μM-1 cm-2). The fabricated sensor was further used for DPA detection in fresh apple extract to evaluate its practicality and demonstrated excellent recoveries ranging from 99.52 to 104.70%.

Integration of iron-manganese layered double hydroxide/tungsten carbide composite: An electrochemical tool for diphenylamine H•+ analysis in environmental samples

Incompetent governance of post-harvest horticultural crops especially apples and pears lead to numerous physiological storage disorders. In order to manage this issue, diphenylamine (DPA) is widely used as an antioxidant and anti-scald agent to preserve fruits from superficial scalds and degradation during storage. As a result, this research focuses on utilizing disposable electrodes constructed with sphere-shaped iron-manganese layered double hydroxide (FeMn-LDH) entrapped tungsten carbide (WC) nanocomposite on its electrochemical performances towards emergent food contaminant, DPA. The importance of the current work is the selection and design of hierarchically structured functional materials especially layered double hydroxides, in virtue of their outstanding properties. These multi-dimensional structures when introduced to form a composite with the highly beneficial tungsten carbide offer excellent characteristics such as exceptional accessibility to active sites, enhanced surface area, and high mass transport and diffusion which serves as advantageous for the electrochemical quantification of DPA. Furthermore, the synergy between FeMn-LDH and WC nanomaterials contributes to the higher active surface area, increased electrical conductivity, fast electron transportation, and ion diffusion, resulting in static properties including a wide linear range (0.01-183.34 μM), low detection limit (1.1 nM), greater sensitivity, selectivity, and reproducibility thus confirming the potential capability of the WC@FeMn-LDH sensor towards the interference-free determination of DPA which validates its practicality and feasibility in real-time. Hence, this work aims to stimulate the fabrication of various advanced hierarchical structures by a simple hydrothermal approach that can have veracity of potential applications.

Surfactant-Assisted Synthesis of Praseodymium Orthovanadate Nanofiber-Supported NiFe-Layered Double Hydroxide Bifunctional Catalyst: The Electrochemical Detection and Degradation of Diphenylamine

Physiological storage disorders are caused by ineffective post-harvest handling of horticultural crops, particularly fruits. To address these post-harvest concerns, diphenylamine (DPAH^•+) is widely used as a preservative to prevent fruit degradation and surface scald during storage around the world. Humans are negatively affected by the use of high concentrations of DPAH^•+ because of the various health complications related to its exposure. As a result, accurate detection and quantification of DPAH^•+ residues in treated fruits are critical. Rare earth metal orthovanadates, which have excellent physical and chemical properties, are potential materials for electrochemical sensors in this area. Herein, we present a simple and direct ultrasonication technique for the surfactant-assisted synthesis of praseodymium orthovanadate (PrVO₄ or PrV) loaded on nickel iron layered double hydroxide (NiFe-LDH) synthesized with deep eutectic solvent assistance, as well as its application as an effective catalyst in the detection and degradation of DPAH^•+ in fruits and water samples. The current work presents supreme electrochemical features of a PrV@NiFe-LDH-modified screen-printed carbon electrode (SPCE) where cetyltrimethylammonium bromide (CTAB) surfactant-driven fabrication of PrV directs the formation of highly qualified engineered structures and the deep eutectic solvent based green synthesis of NiFe-LDH creates hierarchical lamellar structures following the principles of green chemistry. PrV and NiFe-LDH combine to produce a synergistic effect that improves the number of active sites, charge transfer kinetics, and electronic conductivity. Differential pulse voltammetry analysis of PrV@NiFe-LDH/SPCE reveals a dynamic working range (0.005-226.26 μM), increased sensitivity (133.13 μA μM^-1 cm^-2), enhanced photocatalytic activity, and low detection limit (0.001 μM), which are considered significant when compared with the former reported electrodes in the literature for the determination of DPAḢ⁺ for its real-time applications.

Electrocatalytic detection of noxious antioxidant diphenylamine in fruit samples with support of Cu@nanoporous carbon modified sensor

Herein, the facile synthesis of copper(II) and benzene-1,3,5-tricarboxylate (Cu-BTC) and copper nanoporous carbon (Cu@NPC) for the electrochemical detection of diphenylamine (DPA) was systematically investigated. The Cu-BTC and Cu@NPC materials structural, morphological, and thermal stability were evaluated and confirmed using FE-SEM, HR-TEM, XRD, FT-IR, and TGA. The electrocatalytic behavior of sensor materials was examined by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). It is presumed that the structural stability and synergic effect exhibited in Cu@NPC are favorable for enhanced sensitivity and selectivity towards the detection of DPA. The Cu@NPC exhibited a wide linear range (0.09-396.82 μM) and the lowest limit of detection (5 nM). Furthermore, the real sample analysis of the sensor for the detection of DPA in apples and pears confirms its potential capability in practical application.

Development of Two-Dimensional Nanomaterials Based Electrochemical Biosensors on Enhancing the Analysis of Food Toxicants

In recent times, food safety has become a topic of debate as the foodborne diseases triggered by chemical and biological contaminants affect human health and the food industry's profits. Though conventional analytical instrumentation-based food sensors are available, the consumers did not appreciate them because of the drawbacks of complexity, greater number of analysis steps, expensive enzymes, and lack of portability. Hence, designing easy-to-use tests for the rapid analysis of food contaminants has become essential in the food industry. Under this context, electrochemical biosensors have received attention among researchers as they bear the advantages of operational simplicity, portability, stability, easy miniaturization, and low cost. Two-dimensional (2D) nanomaterials have a larger surface area to volume compared to other dimensional nanomaterials. Hence, researchers nowadays are inclined to develop 2D nanomaterials-based electrochemical biosensors to significantly improve the sensor's sensitivity, selectivity, and reproducibility while measuring the food toxicants. In the present review, we compile the contribution of 2D nanomaterials in electrochemical biosensors to test the food toxicants and discuss the future directions in the field. Further, we describe the types of food toxicity, methodologies quantifying food analytes, how the electrochemical food sensor works, and the general biomedical properties of 2D nanomaterials.

Sonochemical fabrication of inorganic nanoparticles for applications in catalysis

Catalysis covers almost all the chemical reactions or processes aiming for many applications. Sonochemistry has emerged in designing and developing the synthesis of nano-structured materials, and the latest progress mainly focuses on the synthetic strategies, product properties as well as catalytic applications. This current review simply presents the sonochemical effects under ultrasound irradiation, roughly describes the ultrasound-synthesized inorganic nano-materials, and highlights the sonochemistry applications in the inorganics-based catalysis processes including reduction, oxidation, degradation, polymerization, etc. Or all in all, the review hopes to provide an integrated understanding of sonochemistry, emphasize the great significance of ultrasound-assisted synthesis in structured materials as a unique strategy, and broaden the updated applications of ultrasound irradiation in the catalysis fields.

Discussions of Fluorescence in Selenium Chemistry: Recently Reported Probes, Particles, and a Clearer Biological Knowledge

In this review from literature appearing over about the past 5 years, we focus on selected selenide reports and related chemistry; we aimed for a digestible, relevant, review intended to be usefully interconnected within the realm of fluorescence and selenium chemistry. Tellurium is mentioned where relevant. Topics include selenium in physics and surfaces, nanoscience, sensing and fluorescence, quantum dots and nanoparticles, Au and oxide nanoparticles quantum dot based, coatings and catalyst poisons, thin film, and aspects of solar energy conversion. Chemosensing is covered, whether small molecule or nanoparticle based, relating to metal ion analytes, H2S, as well as analyte sulfane (biothiols-including glutathione). We cover recent reports of probing and fluorescence when they deal with redox biology aspects. Selenium in therapeutics, medicinal chemistry and skeleton cores is covered. Selenium serves as a constituent for some small molecule sensors and probes. Typically, the selenium is part of the reactive, or active site of the probe; in other cases, it is featured as the analyte, either as a reduced or oxidized form of selenium. Free radicals and ROS are also mentioned; aggregation strategies are treated in some places. Also, the relationship between reduced selenium and oxidized selenium is developed.

Sonochemical catalysis as a unique strategy for the fabrication of nano-/micro-structured inorganics

Ultrasound-assisted approaches, as an important trend in material synthesis, have emerged for designing and creating nano-/micro-structures. This review simply presents the basic principles of ultrasound irradiation including acoustic cavitation, sonochemical effects, physical and/or mechanical effects, and on the basis of the latest progress, it newly summarizes sonochemical catalysis for the fabrication of nano-structured or micro-structured inorganic materials such as metals, alloys, metal compounds, non-metal materials, and inorganic composites, where the theories or mechanisms of catalytic synthetic routes, and the morphologies, structures, sizes, properties and applications of products are described in detail. In the review, a few technological potentials and probable challenges of sonochemical catalysis are also highlighted for the future advance of synthesis methods. Therefore, sonochemical catalysis or ultrasound-assisted synthesis will serve as a unique strategy to reveal its great significance in material fabrication.

Hydrophobic deep eutectic solvent-based ultrasonic-assisted liquid-liquid micro-extraction combined with HPLC-FLD for diphenylamine determination in fruit

In this paper, novel high extraction efficiency hydrophobic eutectic solvents (DESs), n-octanoic acid as a hydrogen bond donor (HBD) and menthol as a hydrogen bond acceptor (HBA), were selected from five hydrophobic DESs to extract trace diphenylamine (DPA) in fruits apple, pear and orange under ultrasonic-assisted liquid-liquid micro-extraction (UA-LLME) technology before high-performance liquid chromatography (HPLC) analysis. Working parameters such as the DESs type, molar ratio, extractant volume, and ultrasonic time of the LLME hydrophobic DESs technology were optimised. Average recoveries between 96% and 108% were obtained on actual samples. This method gave lower detection limit (LOD) than other existing methods due to combining the high-efficiency extraction of hydrophobic DES and high sensitivity of fluorescence detector. This method was sensitive and eco-friendly, and can be used for the determination of trace components in fruits.

Ultrasonication-aided synthesis of nanoplates-like iron molybdate: Fabricated over glassy carbon electrode as an modified electrode for the selective determination of first generation antihistamine drug promethazine hydrochloride

The innovation of novel and proficient nanostructured materials for the precise level determination of pharmaceuticals in biological fluids is quite crucial to the researchers. With this in mind, we synthesized iron molybdate nanoplates (Fe₂(MoO₄)₃; FeMo NPs) via simple ultrasonic-assisted technique (70 kHz with a power of 100 W). The FeMo NPs were used as the efficient electrocatalyst for electrochemical oxidation of first-generation antihistamine drug- Promethazine hydrochloride (PMH). The as-synthesized FeMo NPs were characterized and confirmed by various characterization techniques such as XRD, Raman, FT-IR, FE-SEM, EDX and Elemental mapping analysis and electron impedance spectroscopy (EIS). In addition, the electrochemical characteristic features of FeMo NPs were scrutinized by electrochemical techniques like cyclic voltammetry (CV) and differential pulse voltammetry technique (DPV). Interestingly, the developed FeMo NPs modified glassy carbon electrode (FeMo NPs/GCE) discloses higher peak current with lesser anodic potential on comparing to bare GCE including wider linear range (0.01-68.65 µM), lower detection limit (0.01 µM) and greater sensitivity (0.97 µAµM^-1cm^-2). Moreover, the as-synthesized FeMo NPs applied for selectivity, reproducibility, repeatability and storage ability to investigate the practical viability. In the presence of interfering species like cationic, anionic and biological samples, the oxidation peak current response doesn't cause any variation results disclose good selectivity towards the detection of PMH. Additionally, the practical feasibility of the FeMo NPs/GCE was tested by real samples like, commercial tablet (Phenergan 25 mg Tablets) and lake water samples which give satisfactory recovery results. All the above consequences made clear that the proposed sensor FeMo NPs/GCE exhibits excellent electrochemical behavior for electrochemical determination towards oxidation of antihistamine drug PMH.

Simple sonochemical synthesis of lanthanum tungstate (La2(WO4)3) nanoparticles as an enhanced electrocatalyst for the selective electrochemical determination of anti-scald-inhibitor diphenylamine

In this work, lanthanum tungstate (La₂(WO₄)₃) nanoparticles (NPs) were synthesized by facile sonochemical method (elmasonic P, under-sonication 37/100 kHz, ~60 W energy) and utilized as an electrode material for the selective and sensitive electrochemical determination of anti-scald inhibitor diphenylamine (DPA). The synthesized La₂(WO₄)₃ NPs were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), energy dispersive x-ray spectroscopy (EDAX), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS) analyses. The results revealed that the sonochemically synthesized La₂(WO₄)₃ nanoparticles were with high crystallinity and uniformly distributed nanoparticles like structure. The as-prepared lanthanum tungstate NPs exhibited an excellent electrocatalytic behavior for DPA determination with the lowest detection limit of 0.0024 µM, wide linear range response of 0.01-58.06 µM and a remarkable sensitivity of 1.021 µA µM^-1 cm^-2. Furthermore, La₂(WO₄)₃ NPs showed a good recovery to DPA in apple juice sample. Besides, the electrochemical mechanism of the DPA oxidation reaction was provided in detail.

Electrochemical detection of toxic anti-scald agent diphenylamine using oxidized carbon nanofiber encapsulated titanium carbide electrocatalyst

Two dimensional (2D) titanium carbide (Ti-C) is an analogues of graphene have tremendous attention in recent years due to their high electrical conductivity and catalytic activity. Herein, we have synthesized Ti-C micro particles based on the template-assisted method and subsequently integrated with oxidized carbon nanofiber (f-CNF) through ultrasonication technique. The prepared Ti-C/f-CNF composite was subjected to various structural and morphological characterization techniques including the X-ray diffraction (XRD), scanning electron microscope (SEM), Energy Dispersive X-ray (EDX) and X-ray photoelectron spectroscopy (XPS). The all followed studies confirmed the formation and crystalline nature of prepared Ti-C/f-CNF nanocomposite. Further, the proposed Ti-C/f-CNF composite modified electrode was successfully applied as an electrocatalyst for the electrochemical detection of diphenylamine (DPA) in food. DPA is known as an anti-scald agent used to post harvest treatment of fruits. However, the higher concentration of DPA causes some hazardous side effects to human. Thus, the detection of DPA is an important concern in healthcare research. Eventually, the proposed Ti-C/f-CNF/SPCE exhibited ultra-low detection limit of (0.003 μM) with a linear range of 0.04-56.82 μM towards the detection of DPA. Moreover, the practicability of the proposed sensor was tested by real sample analysis by using fresh apple extract. Remarkably, the proposed sensor showed an excellent recovery range from 106.8% to 108% for the detection of DPA in spiked apple extract. Finally, we concluded that the integration of f-CNF with Ti-C is significantly enhanced both electrical conductivity and electrocatalytic activity for sensor application.