Facile synthesis of single-crystalline Fe-doped copper vanadate nanoparticles for the voltammetric monitoring of lethal hazardous fungicide carbendazim

Integrated photocatalysis adsorption processes for oxytetracycline removal: using volborthite and its composite with g-C3N4

The photocatalytic-adsorption performance of the composites of volborthite (CuVA) and graphitic carbon nitride (g-C3N4) was studied in this work using oxytetracycline (OTC) as model pollutant under LED light irradiation. CuVA at different weight percentages (10, 30, 50), namely, C10, C30, and C50, were loaded onto graphitic carbon nitride using wet chemical method. The physical, chemical, and optical properties were evaluated via various analytical techniques. Through integrated adsorption-photocatalytic process, no significant photocatalytic reaction occurred in g-C3N4 and the composite even after 4 h of irradiation. The setup was modified such that each run was conducted in the presence and absence of light. Aside from photolysis and g-C3N4, all composites performed better under the presence of light in which CuVA improved the most from ~ 50% down to ~ 20% of initial concentration. CuVA performed almost identically (80% removal of OTC) under the presence of light irradiation at ambient temperature (22 °C) and in the dark at 32 °C, confirming that temperature was the contributing factor to the improvement instead of light. CuVA exhibited excellent adsorption capacity of 171 mg/g and adsorption rate of 90% towards the removal of highly concentrated OTC (100 mg/L) under optimized parameters of pH 5.0 and at 42 °C after 3 h of adsorption process. Life cycle assessment revealed that close to 50% of fresh 100 ppm OTC could be removed after five cycles without any desorption process.

Facile Synthesis of Platinum Nanoparticle-Embedded Reduced Graphene Oxide for the Detection of Carbendazim

In recent years, there has been a significant interest in the advancement of electrochemical sensing platforms to detect pesticides with high sensitivity and selectivity. Current research presents a novel approach utilising platinum nanoparticles (NPs) and reduced graphene oxide deposited on a glassy carbon electrode (Pt-rGO/GCE) for direct electrochemical measurement of carbendazim (CBZ). A straightforward one-step electrodeposition process was applied to prepare the Pt-rGO sensing platform. The incorporation of conductive rGO nanosheets along with distinctive structured Pt NPs significantly enhanced the effective electrode surface area and electron transfer of CBZ. Additionally, when exposed to 50 µM CBZ, Pt-rGO/GCE exhibited a higher current response compared to the bare electrode. Further investigations were performed to analyse and optimise the experimental parameters that could influence pesticide detection. Under the optimised conditions of pH 7 and 5 min of accumulation time, the Pt-rGO/GCE sensor showed a linear concentration detection range from 0.1 µM to 50 µM, with a detection limit of 3.46 nM. The fabricated sensor was successfully employed for CBZ detection in milk and tap water with 98.88% and 98.57% recovery, respectively. The fabricated sensor showed higher sensitivity and reproducibility, thus indicating the potential of this technology in the development of reliable sensors for the detection of CBZ or similar pesticides in forthcoming applications.

Impedimetric sensing platform for sensitive carbendazim detection using MOCVD-synthesized copper graphene

Nanostructures of graphene were synthesized for electrochemical carbendazim (CBZ) fungicide detection via metal-organic chemical vapor deposition (MOCVD). The arduous process of graphene transfer is eliminated by this innovative approach to MOCVD graphene development. It also generates several defects and impurities and ultimately leads to the uniform deposition of graphene on SiO2/Si. SEM, EDX, and ICP-AES were used to assess the morphological properties and chemical composition of the materials. To obtain in-depth knowledge of the entire system, the electrochemical behavior was also investigated using voltammetric techniques and electrochemical impedance spectroscopy. The interaction of particles of copper with CBZ and the enhanced surface area of graphene, which causes a strong oxidation current, has been demonstrated to achieve the ideal CBZ sensing behavior. The electrode responded linearly at CBZ concentration levels of 1 to 50 nM, and the sensitivity of the sensing materials was estimated to be 0.0337 Ω nM-1. The statistical analysis validates the electrode's exceptional selectivity and remarkable reproducibility in determining CBZ.

Electroanalytical overview: the sensing of carbendazim

Carbendazim is a broad-spectrum systemic fungicide that is used to control various fungal diseases in agriculture, horticulture, and forestry. Carbendazim is also used in post-harvest applications to prevent fungal growth on fruits and vegetables during storage and transportation. Carbendazim is regulated in many countries and banned in others, thus, there is a need for the sensing of carbendazim to ensure that high levels are avoided which can result in potential health risks. One approach is the use of electroanalytical sensors which present a rapid, but highly selective and sensitive output, whilst being economical and providing portable sensing platforms to support on-site analysis. In this minireview, we report on the electroanalytical sensing of carbendazim overviewing recent advances, helping to elucidate the electrochemical mechanism and provide conclusions and future perspectives of this field.

Engineered tenorite structure of barium-enriched copper oxide for on-site monitoring of cytotoxic methotrexate in environmental samples

Emerging pharmaceutical pollutants pose a threat to both human and environmental health. The removal and monitoring of such pollutants necessitate the use of practical on-site monitoring devices; however, the designs of such devices are underdeveloped. This study involves the fabrication of a low-cost sensor based on barium-incorporated copper oxide (Ba-CuO) for the on-site monitoring of the cytotoxic drug methotrexate (MTRX) in water and sediment samples. The tenorite structure of CuO was slightly enriched with Ba ions at the td sites, distorting the tetrahedron and enhancing its electrochemical properties. Ba-CuO was obtained from Cu(NO₃)₂ and Ba(OH)₂ by a ligand exchange protocol and was characterized using X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, field-emission scanning electron microscopy, transmission electron microscopy, and energy dispersive X-ray analysis. In addition, the Ba-CuO sensor was tested under various conditions, and it could detect MTRX at concentrations as low as 0.4 nM, with a high sensitivity of 1.3567 µA µM^-1 cm^-2. On-site monitoring yielded recoveries of greater than 93 % from spiked samples, thus exhibiting excellent reproducibility and stability. Therefore, the developed method is practical and has no matrix effect on the MTRX sensor.

Rational design of Nd2O3 decorated functionalized carbon nanofiber composite for selective electrochemical detection of carbendazim fungicides in vegetables, water, and soil samples

Abuse of carbendazim (CBZ) leaves excessive pesticide residues on agricultural products, which endangers human health because of the residues' high concentrations. Hence, a composite consisting of functionalized carbon nanofibers (f-CNF) with neodymium oxide (Nd₂O₃) was fabricated to monitor CBZ at trace levels. The Nd₂O₃/f-CNF composite-modified electrode displays higher electro-oxidation ability towards CBZ than Nd₂O₃ and f-CNF-modified electrodes. The combined unique properties of Nd₂O₃ and f-CNF result in a substantial specific surface area, superior structural stability, and excellent electrocatalytic activity of the composite yielding enhanced sensitivity to detecting CBZ with a detection limit of 4.3 nM. Also, the fabricated sensor electrode can detect CBZ in the linear concentration range of up to 243.0 μM with high selectivity, appropriate reproducibility, and stability. A demonstration of the sensing capability of CBZ in vegetables, water, and soil samples was reported paving the way for its use in practical applications.

Highly sensitive electrochemical detection of carbendazim residues in water by synergistic enhancement of nitrogen-doped carbon nanohorns and polyethyleneimine modified carbon nanotubes

Carbendazim (CBZ) can protect crops from pathogens, but it is also easy to cause pesticide residues, threatening human health. In our work, an electrochemical sensor based on nitrogen-doped carbon nanohorns (N-CNHs) and polyethyleneimine-modified carbon nanotubes (PEI-CNTs) was developed for the detection of CBZ content in water. The results showed that N-doping provided the CN bonds for CNHs and improved the electrochemical reaction performance of N-CNHs surface. With the participation of PEI, the surface of CNTs was positively charged and contained a large number of NH bonds, which not only promoted the electrostatic assembly of N-CNHs and PEI-CNTs but also was beneficial to further enriching CBZ. After further ultrasound-assisted assembly of N-CNHs and PEI-CNTs, the electron transfer capacity, electrochemical active surface area, and catalytic activity of N-CNHs/PEI-CNTs were significantly improved. The sensor performed a wider linear range (15 nmol/L ~ 70 μmol/L), low detection limit (4 nmol/L) and satisfactory recovery (87.33 % ~ 117.67 %) under the optimal conditions. In addition, the sensor had good anti-interference, reproducibility, and stability. Our work provided a new strategy for quantification of CBZ in environment.

Effect of the Ni3TeO6 phase in a Ni2Te3O8/expanded graphite composite on the electrochemical monitoring of metribuzin residue in soil and water samples

Growing food demand and climate change have led to the development of various pest control agents to increase crop yields. Although pesticides help meet the food demand, they cause harm to human health and the environment. Metribuzin (MTBZ) is one of the common herbicides used for controlling weeds. Therefore, monitoring MTBZ residues in soil and water bodies is essential for decreasing risk to the environment and human health. This paper reports a highly selective and sensitive electrochemical sensor electrode based on a Ni₃TeO₆-phase-integrated Ni₂Te₃O₈/expanded graphite (referred to here as NTO-eGR) composite for the detection of MTBZ. The NTO-eGR composite was prepared by a one-step low-temperature hydrothermal method and characterized by X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, and electron microscopy techniques. The Ni₃TeO₆ phase was found to be an active component in the NTO/eGR composite, which exhibited satisfactory analytical performance in MTBZ detection with a sensitivity of 1.454 µA µM^-1 cm^-2. Moreover, the NTO-eGR electrode exhibited high selectivity to MTBZ even in the presence of a five-fold excess of interfering species in water and soil samples. The studies on practical applicability revealed that NTO-eGR exhibits good reproducibility with a relative standard deviation of 2.67% (n = 5). Moreover, good recoveries of greater than 90% were achieved in the determination of MTBZ in soil and water samples. Hence, the NTO-eGR sensor electrode is highly suitable for the rapid on-site determination of MTBZ.

Synthesis and characterizations of iron antimony oxide nanoparticles and its applications in electrochemical detection of carbendazim in apple juice and paddy water samples

This study reports a facile sonohydrolysis synthesis route to prepare the iron antimony oxide (FeSbO₄) nanoparticles for the trace level electrochemical sensing of fungicide carbendazim (CRBZ). As prepared FeSbO₄ nanoparticles show a nano-cubes-like morphology with uniform distributions that crystallized in the tetragonal phase. The diffraction studies reveal that the FeSbO₄ nanoparticles have high crystallinity and high purity. Furthermore, the other structural properties and morphology are characterized by XRD, Raman, XPS, HRTEM, and FESEM analysis. The electrochemical characterizations of FeSbO₄ modified GCE towards the detection of CRBZ are performed by cyclic voltammetry and chronoamperometry techniques. The FeSbO₄/GCE exhibits a linear range from 0.01 µmol L^-1 to 64.3 µmol L^-1, the sensitivity of 0.68 µA cm^-2 µM^-1, and the LOD of 5.4 nmol L^-1. Moreover, the FeSbO₄/GCE delivered high selectivity among the possibly interfering compounds. Also, our projected FeSbO₄/GCE electrode material shows good recoveries in apple juice and paddy water real samples.