Surface engineering of roselike lanthanum molybdate electrocatalyst modified screen-printed carbon electrode for robust and highly sensitive sensing of antibiotic drug

An electrochemical signal amplification using functionalized carbon nanofiber integrated manganese molybdate nanocomposite for rapid detection of vanillin in food samples

Vanillin, a widely used flavoring agent in food, pharmaceuticals, and cosmetics, can cause health issues such as liver dysfunction and nausea when consumed excessively. Therefore, it is essential to monitor and control the vanillin level. This study presents the development of sensitive and cost-effective electrochemical sensor for vanillin detection, utilizing manganese molybdate (MnMoO4) nanoparticles integrated with functionalized carbon nanofibers (f-CNF) nanocomposite. The chemical composition and morphology of MnMoO4@f-CNF were analyzed using X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, and transition electron microscopy. The fabricated MnMoO4@f-CNF sensor achieved the low limit of detection of 0.027 μM and wide linear range of 1.25-487.5 and 587.5-1500 μM in amperometry method towards vanillin detection. The practical feasibility of the prepared sensor towards vanillin was tested in food samples and confirmed the sensor's reliability. This study demonstrates the MnMoO4@f-CNF sensor's potential for rapid, accurate, and selective detection of vanillin in food safety and quality control.

Medium entropy FeCoNi nanoalloy supported on reduced graphene oxide for efficient electrochemical detection of roxarsone in food samples

Herein, a novel FeCoNi(b)-800 ternary metal nanoalloy was uniformly mixed with reduced graphene oxide (RGO) to synthesize the FeCoNi(b)-800@RGO(2:1) composite. The addition of RGO not only stopped the accumulation of FeCoNi(b)-800 alloy, but also heightened the electrocatalytic activity of composite. Particularly, the FeCoNi(b)-800@RGO(2:1) composite displayed the significantly strong electrocatalytic capacity for the reduction of roxarsone (ROX). Furthermore, the FeCoNi(b)-800@RGO(2:1) composite possessed enough porosity and metal catalytic sites, facilitating the transport and electrochemical reduction of the ROX. Thus, the FeCoNi(b)-800@RGO(2:1) composite modified glassy carbon electrode (FeCoNi(b)-800@RGO(2:1)/GCE) showed the superb electrochemical detection effect for ROX with relatively wide working range (0.1-1500 μM) and low detection limit (0.013 μM). Importantly, the FeCoNi(b)-800@RGO(2:1)/GCE sensor could accurately determine the contents of ROX in actual pork, chicken, duck and egg samples, indicating that it had good suitability in food safety monitoring.

3D/2D-Bismuth Oxybromide Spheres with Selenium-Doped Graphitic Carbon Nitride Sheets: An Efficient Electrocatalyst for the Detection of Arsenic Drug Roxarsone

Heavy metals are crucial carcinogenic agents threatening the environment and living habituates. Among them, arsenic (As) is an important metalloid that is categorized as a group I toxic carcinogen. Roxarsone (RX) is an organoarsenic antibiotic compound primarily used as a veterinarian drug and growth promoter for poultry animals. The extensive usage of RX increased the accumulation of As in living beings and the ecosystem. Therefore, we have prepared an electrochemical sensor based on 3D bismuth oxybromide with 2D selenium-doped graphitic carbon nitride (BOB/SCN) electrocatalyst for the rapid detection of RX. The elemental and structural details were thoroughly investigated with several spectroscopic techniques. The electrochemical properties were measured by impedance and voltammetric measurements. The electrocatalytic behavior toward the RX was estimated with different voltammetric methods. Therefore, our BOB/SCN-based electrochemical sensor demonstrated a low detection limit (2.3 nM), low quantification value (7.7 nM), optimal sensitivity (0.675 μA μM-1 cm-2), and good linear ranges (0.01-77 and 77-857 μM). Additionally, this sensor showed good electrochemical performance and was applied to monitor the RX in various real samples with remarkable recoveries. Based on these results, our BOB/SCN sensor is a promising electrochemical platform for determining RX.

Design and fabrication of La-based perovskites incorporated with functionalized carbon nanofibers for the electrochemical detection of roxarsone in water and food samples

The pentavalent arsenic compound roxarsone (RSN) is used as a feed additive in poultry for rapid growth, eventually ending up in poultry litter. Poultry litter contains chicken manure, which plays a vital role as an affordable fertilizer by providing rich nutrients to agricultural land. Consequently, the extensive use of poultry droppings serves as a conduit for the spread of toxic forms of arsenic in the soil and surface water. RSN can be easily oxidized to release highly carcinogenic As(III) and As(IV) species. Thus, investigations were conducted for the sensitive detection of RSN electrochemically by developing a sensor material based on lanthanum manganese oxide (LMO) and functionalized carbon nanofibers (f-CNFs). The successfully synthesised LMO/f-CNF composite was confirmed by chemical, compositional, and morphological studies. The electrochemical activity of the prepared composite material was examined using cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The obtained results confirmed that LMO/f-CNF showed enhanced electrocatalytic activity and improved current response with a good linear range (0.01-0.78 μM and 2.08-497 μM, respectively), exhibiting a low limit of detection (LOD) of 0.004 μM with a high sensitivity of 13.24 μA μM-1 cm-2 towards the detection of RSN. The noteworthy features of LMO/f-CNF composite with its superior electrochemical performance enabled reliable reproducibility, exceptional stability and reliable practical application in the analysis of tap water and food sample, affording a recovery range of 86.1-98.87%.

Electrochemical determination of Roxarsone using preconcentration-based signal amplification on modified screen-printed electrode

A lab-made screen-printed electrode based on poly(ethylene terephthalate) (PET) substrate modified with a hybrid film containing gold nanoparticles-decorated graphene (AuNPs-GRA/PET-SPE) was employed for the voltammetric determination of Roxarsone (ROX) in chicken purge and river water samples. The electrode exhibited an increased electroactive area and enhanced charge transfer due to the nanostructured matrix. The electrochemical determination involved a preconcentration approach with a reduction step of ROX at a constant potential of -0.6 V, followed by voltammetric sweep towards the oxidation of the adsorbed hydroxylamine at 0.32 V. The methodology achieved a limit of detection of 60 nM and 97 nM for ROX in diluted river water and chicken purge samples, respectively. This effective methodology offers a promising tool for monitoring ROX levels in environmental and food samples.

Diclofenac-Impregnated Mesoporous Carbon-Based Electrode Material for the Analysis of the Arsenic Drug Roxarsone

This paper describes a novel electrode material, diclofenac-impregnated mesoporous carbon modified with a cationic surfactant, cetyltrimethylammonium bromide (DF-CMK-3/CTAB), for ultratrace analysis of the arsenic drug roxarsone (ROX). DF-CMK-3 amorphous carbon is a material with a high specific surface area and well-defined, hexagonally ordered, thin mesopores. The functional groups attached to the carbonaceous surface, such as chromene and pyron-like oxygen groups, lactam, and aromatic carbon rings, have the basic character and they can donate electrons. Modification of DF-CMK-3 with a CTAB layer significantly increases the analytical signal due to electrostatic interactions between the cationic surfactant and the anion form of ROX in the acidic medium. The voltammetric procedure at the glassy carbon sensor modified with DF-CMK-3/CTAB exhibited excellent sensitivity (limit of detection of 9.6 × 10-11 M) with a wide range of linearity from 5.0 × 10-10 to 1.0 × 10-4 M. Analysis of real samples (treated municipal wastewater and river water) showed recoveries from 96 to 102% without applying the complicated sample pretreatment step. The sensor demonstrated excellent sensitivity in the analysis of the arsenic drug ROX in the presence of interferences in environmental water samples.

Glassy Carbon Modified with Cationic Surfactant (GCE/CTAB) as Electrode Material for Fast and Simple Analysis of the Arsenic Drug Roxarsone

For the fast and simple sensing of the arsenic drug roxarsone (ROX), the development of a glassy carbon electrode (GCE) modified with cationic surfactant (cetyltrimethylammonium bromide, CTAB) material is critical. The CTAB-modified glassy carbon electrode, in contrast to the unmodified one, showed excellent behavior for electrochemical reduction of ROX using cyclic voltammetry (CV) and square-wave adsorptive stripping voltammetry (SWAdSV) techniques. CV studies reveal an irreversible reduction process of NO₂ to NH-OH in the ROX molecule in NaAc-HAc buffer (pH = 5.6). The electrode material was characterized using CV and electrochemical impedance spectroscopy. The experiments show that the surfactant-modified material has faster electron transfer and a higher active surface area, and permits a diffusion-adsorption-controlled process. After optimization, the SWAdSV procedure with GCE/CTAB has linear ranges of 0.001-0.02 and 0.02-20 µM, and a detection limit of 0.13 nM. Furthermore, the procedure successfully determined roxarsone in river water samples.

Fabrication of Praseodymium Vanadate Nanoparticles on Disposable Strip for Rapid and Real-Time Amperometric Sensing of Arsenic Drug Roxarsone

Nanomaterials have versatile properties owing to their high surface-to-volume ratio and can thus be used in a variety of applications. This work focused on applying a facile hydrothermal strategy to prepare praseodymium vanadate nanoparticles due to the importance of nanoparticles in today's society and the fact that their synthesis might be a challenging endeavor. The structural and morphological characterizations were carried out to confirm the influence of the optimizations on the reaction's outcomes, which revealed praseodymium vanadate (PrVO₄) with a tetragonal crystal system. In this regard, the proposed development of electrochemical sensors based on the PrVO₄ nanocatalyst for the real-time detection of arsenic drug roxarsone (RXS) is a primary concern. The detection was measured by amperometric (i-t) signals where PrVO₄/SPCE, as a new electrochemical sensing medium for RXS detection, increased the sensitivity of the sensor to about ∼2.5 folds compared to the previously reported ones. In the concentration range of 0.001-551.78 μM, the suggested PrVO₄/SPCE sensor has a high sensitivity for RXS, with a detection limit of 0.4 nM. Furthermore, the impact of several selected potential interferences, operational stability (2000 s), and reproducibility measurements have no discernible effect on RXS sensing, making it the ideal sensing device feasible for technical analysis. The real-time analysis reveals the excellent efficiency and reliability of the prosed sensor toward RXS detection with favorable recovery ranges between ±97.00-99.66% for chicken, egg, water, and urine samples.

One material, many possibilities via enrichment of luminescence in La2Zr2O7:Tb3+ nanophosphors for forensic stimuli aided applications

Engineering a single material with multidirectional applications is crucial for improving productivity, low cost, flexibility, least power consumption, etc. To achieve these requirements, novel design structures and high-performance materials are in urgent need. Lanthanide-doped nanophosphors have the greatest strengths and ability in order to tune their applications in various dimensions. However, applications of nanophosphor in latent fingerprints visualization, anti-counterfeiting, and luminescent gels/films are still in their infancy. This study demonstrated a simple strategy to enhance the luminescence of Tb³⁺ (1-11 mol %) doped La₂Zr₂O₇ nanophosphors by conjugating various fluxes via a simple solution combustion route. The photoluminescence emission spectra reveal intense peaks at ~ 491, 546, 587, and 622 nm, which arises from ⁵D₄ → ⁷F_J (J = 6, 5, 4, 3) transitions of Tb³⁺ ions, respectively. The highest emission intensity was achieved in the NH₄Cl flux assisted nanophosphor as compared to NaBr and NH₄F assisted samples. The colorimetric images of fingerprints visualized using the optimized nanophosphor on forensic related surfaces exhibit level -III ridge details, including sweat pores, the width of the ridges, bifurcation angle, and the successive distance between sweat pores, etc. These results are decisive parameters that clearly support the statement "no two persons have ever been found to have the same fingerprints". The anti-counterfeiting security ink was formulated using optimized nanophosphor and various patterns were designed by simple screen printing and dip pen technologies. The encoded information was decrypted only under ultraviolet 254 nm light. All the designed patterns are exhibit not just what it looks/feel like and how better it works. As a synergetic contribution of enhanced luminescence of the prepared nanophosphor, the green-emissive films were fabricated, which display excellent flexibility, uniformity, and transparency in the normal and ultraviolet 254 nm light illumination. The aforementioned results revealed that the prepared NH₄Cl flux-assisted La₂Zr₂O₇: Tb³⁺(7 mol %) NPs are considered to be the best candidate for multi-dimensional applications.

Ultrasensitive detection of four organic arsenic compounds at the same time using a five-link cardboard-based assay

In order to effectively control the excessive use of organic arsenic reagents in livestock and poultry products, there is an urgent need to develop a method for rapid detection of multiple organic arsenic reagents. In this study, two haptens were designed and derivatized around the structural formula of roxarsone, and a highly-sensitive group-selective mAb 3F2 was prepared, which can simultaneously detect roxarsone, 4-aminophenylarsonic acid, 2-aminophenylarsonic acid and phenylarsonic acid. We further developed a colloidal gold immunochromatographic test strip (ICS) and prepared a five-link card that can simultaneously detect four organic arsenics in chicken and pork samples. Its quantitative detection limits (LOQ) for the four compounds in chicken and pork samples were 0.06 and 0.32 ng/mL, 0.11 and 0.29 ng/mL, 0.34 and 0.99 ng/mL, and 0.88 and 1.5 ng/mL, respectively. This multi-ICS detection provides a powerful tool for the on-site detection and rapid screening of organic arsenic reagents in actual samples.

Electrochemical Behavior of Three-Dimensional Cobalt Manganate with Flowerlike Structures for Effective Roxarsone Sensing

Rational design and construction of the finest electrocatalytic materials are important for improving the performance of electrochemical sensors. Spinel bioxides based on cobalt manganate (CoMn₂O₄) are of particular importance for electrochemical sensors due to their excellent catalytic performance. In this study, three-dimensional CoMn₂O₄ with the petal-free, flowerlike structure is synthesized by facile hydrothermal and calcination methods for the electrochemical sensing of roxarsone (RXS). The effect of calcination temperature on the characteristics of CoMn₂O₄ was thoroughly studied by in-depth electron microscopic, spectroscopic, and analytical methods. Compared to previous reports, CoMn₂O₄-modified screen-printed carbon electrodes display superior performance for the RXS detection, including a wide linear range (0.01-0.84 μM; 0.84-1130 μM), a low limit of detection (0.002 μM), and a high sensitivity (33.13 μA μM^-1 cm^-2). The remarkable electrocatalytic performance can be attributed to its excellent physical properties, such as good conductivity, hybrid architectures, high specific surface area, and rapid electron transportation. More significantly, the proposed electrochemical sensor presents excellent selectivity, good stability, and high reproducibility. Besides, the detection of RXS in river water samples using the CoMn₂O₄-based electrochemical sensor shows satisfactory recovery values in the range of 98.00-99.80%. This work opens a new strategy to design an electrocatalyst with the hybrid architecture for high-performance electrochemical sensing.