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

Rare earth orthovanadate (REM-VO4; REM = Pr, Gd, and Sm)-based sensors for selective and simultaneous detection of furazolidone and metronidazole

Antibiotics are vital tools in the fight against bacterial infections, with furazolidone (FD) and metronidazole (MD) being widely used to target pathogens like G. lamblia and H. pylori. However, overuse of these antibiotics can lead to serious health complications, highlighting the urgent need for accurate, real-time detection of these drugs at precise levels. In this study, we explore the use of differential pulse voltammetry (DPV) for detecting FD and MD with high sensitivity, employing a dual detection method. To enhance detection, we developed a sensor using rare earth metal-based orthovanadates (REM-VO4, where REM = Pr, Gd, and Sm) as electrode modifiers. These materials offer exceptional surface control, boosting the sensor's sensitivity and selectivity. Among the different configurations, the SmVO4-modified glassy carbon electrode (SmV/GCE) stands out, demonstrating the lowest charge transfer resistance (Rct = 56.82 Ω) and the largest electrochemical surface area (A = 0.11 cm2). SmVO4's unique nanostructure, with its high electrochemically active surface area and hollow structure, is key to its impressive performance. This sensor not only provides the lowest limits of detection (0.0009 μM for FD and 0.0036 μM for MD individually, and 0.0015 μM and 0.0049 μM for simultaneous detection) but also shows excellent anti-interference, repeatability, and reproducibility. Furthermore, SmV/GCE has been successfully applied for real-time analysis of biological and environmental samples, offering recoveries between 97.33 to 99.60%, demonstrating its practical potential for precise antibiotic monitoring.

Construction of an electrochemical sensor towards environmental hazardous 4-nitrophenol based on Nd(OH)3-embedded VSe2 nanocomposite

The toxicity of 4-nitrophenol (4-NP) is one of the most common threats to the environment; therefore, developing a simple and sensitive analytical method to detect 4-NP is crucial. In this study, we prepared the Nd(OH)3/VSe2 nanocomposite using the simple hydrothermally assisted ultrasonication method and it was used to detect the 4-NP. Different characterization techniques were used to investigate the morphological and chemical compositions of Nd(OH)3/VSe2 nanocomposite. All of these investigations revealed that Nd(OH)3 nanoparticles were finely dispersed on the surface of the VSe2 nanosheet. The electrical conductivity of our prepared samples was evaluated by the electrochemical impedance spectroscopic technique. The CV and DPV methods were used to explore the electrochemical activity of 4-NP at the Nd(OH)3/VSe2/GCE sensor which exhibited a wide linear range (0.001 to 640 µM), low limit of detection (0.008 µM), and good sensitivity (0.41 µA µM-1 cm-2), respectively. Additionally, Nd(OH)3/VSe2/GCE sensor was tested in water samples for the detection of 4-NP, which exhibited good recovery results. The Nd(OH)3/VSe2 electrode material is a novel one for the electrochemical sensor field, and the obtained overall results also proved that our proposed material is an active material for sensor applications.

Construction of functionalized carbon nanotube@metal oxide nanocomposite for high-performance electrochemical measurement of antipyretic drug in water samples

Acetaminophen (AP) acts as supportive clinical therapy for fever and dysmenorrhea. An overdose of AP may result in severe adverse diseases, such as liver dysfunction. In addition, AP is a key-listed environmental pollutant, which is difficult to degrade in the environment and has serious effects on living bodies. Therefore, the simple and quantitative determination of AP is highly relevant today. In this work, tin dioxide (SnO2) nanoparticles with functionalized multi-walled carbon nanotube (f-MWCNT) as a hybrid composite were prepared by hydrothermal-assisted synthesis. The composite material was characterized by various spectral, morphological, and electrochemical tests. Electrochemical investigations were conducted using a SnO2@f-MWCNT-reinforced electrode for the detection of AP. The composite electrode exhibited better functional properties, which facilitated electron transfer and enhanced electrical conductivity. The calculated low detection limit (LOD) of 0.36 nM is with a wide linear range of concentration from 0.001 to 673 µM. Additionally, the SnO2@f-MWCNT-modified electrode exhibited good anti-interference capability, repeatability, reproducibility, storage, and operational stability. The developed SnO2@f-MWCNT-modified electrode was applied to practical analysis in diverse water matrices (river, drinking, and pond) with acceptable recovery percentages. A synthesized nanoscale metal oxide electrocatalyst is of great interest and an active research area that serves as a foundation for the development of new, cost-effective electrochemical antibiotic drug sensors.

Synergistically Enhanced Electrochemical Sensing of Food Adulterant in Milk Sample at Erbium Vanadate/Graphitic Carbon Nitride Composite

Dimetridazole (DMZ), a nitroimidazole derivative, is a notable antibiotic that has garnered growing interest in the medical community owing to its noteworthy pharmacological and toxicological properties. Increasing interest is being directed toward developing high-performance sensors for continuous monitoring of DMZ in food samples. This research investigated an electrochemical sensor-based nano-sized ErVO4 attached to a sheet-like g-CN-coated glassy carbon electrode to determine dimetridazole (DMZ). The chemical structure and morphological characterization of synthesized ErVO4@g-CN were analyzed with XRD, FTIR, TEM, and EDS. Irregular shapes of ErVO4 nanoparticles are approximately 15 nm. Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were followed to examine the electrochemical performance in pH 7 phosphate buffer solution for higher performance. This electrochemical sensor showed a low detection limit (LOD) of 1 nM over a wide linear range of 0.5 to 863.5 µM. Also, selectivity, stability, repeatability, and reproducibility studies were investigated. Furthermore, this electrochemical sensor was applied to real-time milk sample analysis for the detection of analytes.

Electrochemical determination of vanillin using 2D/2D heterostructure based on ZnCr-layered double hydroxide and g-CN

A ZnCr-LDH@g-CN composite was synthesized through a one-pot hydrothermal method to fabricate an effective sensor for detecting vanillin. The prepared material was investigated by using structural and physical studies. Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) with applied potential (Epa =  + 0.68 V vs Ag/AgCl) were used to examine the electrochemical behavior of vanillin. The fabricated electrode exhibited a linear detection range of 0.001-143.2 μM, a low detection limit of 0.9 nM, sensitivity of 4.72 µA µM-1 cm-2, selectivity, stability, reproducibility (RSD = 4.40%), and repeatability (RSD = 4.46%). The optimized sensor was successfully applied to detect vanillin in real samples, including ice cream, chocolate, and water, and their recovery was 98.46-99.80%. Overall, the ZnCr-LDH@g-CN composite sensor offers a promising solution for precise vanillin detection.

Lanthanum vanadate-based carbon nanocomposite as an electrochemical probe for amperometric detection of theophylline in real food samples

Theophylline (THP) is an emerging drug for chronic obstructive pulmonary disease whose side effects can be greatly affected by caffeine-containing real foods. Because an overdose of this substance can cause respiratory and neurological damage, producing a fast and accurate analytical procedure is critical. Based on a cutting-edge hybrid nanocomposite, this study was used to construct an electrochemical sensor for the accurate detection of THP. Spectroscopy and morphological investigation supported the easy synthesis of tetragonal-LaVO₄ (t-LV) nanopellets and LV@CNF hybrid nanocomposite. To detect THP, a highly dispersed LV@CNF nanocomposite was modified on a glassy carbon electrode as a sensing substrate. By amperometric technique, the sensor shows a wide linear range of 0.01-1070 μM, low limit of detection (2.63 nM), and sensitivity (0.228 μA μM^-1 cm^-2). Finally, the current technique was successfully used to identify THP in real food samples (chocolate, coffee and black tea).

Emerging carbonate anion intercalated- ZnCr-layered double hydroxide/vanadium carbide nanocomposite: Sustainable design strategies based on disposal electrochemical sensor for diethofencarb fungicide monitoring

Diethofencarb (DFC) is widely used in agriculture to fight against plant fungal attacks and enhance food crop production. On the other hand, the National food safety standard has set the overall maximum residual limit (MRL) of DFC to be 1 mg/kg. Hence it becomes essential to limit their usage, and it is vital to quantify the amount of DFC present in real-life samples to safeguard the health and environmental well-being. Here, we introduce a simple hydrothermal procedure for preparing vanadium carbide (VC) anchored by ZnCr-LDH. The sustainably designed electrochemical sensor for the detection of DFC portrayed high electro-active surface area, conductivity, rapid-electron transport ratio, and high ion diffusion parameters. The obtained structural and morphological information confirms the enriched electrochemical activity of the ZnCr-LDH/VC/SPCE towards DFC. The ZnCr-LDH/VC/SPCE electrode has displayed exceptional characteristics with DPV resulting in a vast linear response (0.01-228 μM), and lower LOD (2 nM) with high sensitivity. Real-sample analysis was carried out to demonstrate the specificity of the electrode with an acceptable recovery in both water (±98.75-99.70%) and tomato (±98.00-99.75%) samples.

Incorporation of carbon black into a sonogel matrix: improving antifouling properties of a conducting polymer ceramic nanocomposite

A new electrochemical sensor device has been developed through the modification of a polyaniline-silicon oxide network with carbon black (CB). Enhanced electrical conductivity and antifouling properties have been achieved due to the integration of this cheap nanomaterial into the bulk of the sensor. The structure of the developed material was characterized using Fourier transform infrared spectroscopy, energy-dispersive X-ray spectroscopy, and scanning electron microscopy techniques. Cyclic voltammetry was used to characterize electrochemically the Sonogel-Carbon/Carbon Black-PANI (SNG-C/CB-PANI) sensor device. In addition, differential pulse voltammetry was employed to evaluate the analytical response of the sensor towards sundry chlorophenols, common environmental hazards in aqueous ecosystems. The modified sensor material showed excellent antifouling properties, which led to a better electroanalytical performance than the one displayed with the bare sensor. Notably, a sensitivity of 5.48 × 10³ μA mM^-1 cm^-2 and a limit of detection of 0.83 μM were obtained in the determination of 4-chloro-3-methylphenol (PCMC) at a working potential of 0.78 V (vs. 3 M Ag/AgCl/KCl), along with proficient values of reproducibility and repeatability (relative standard deviation < 3%). Finally, the analysis of PCMC was carried out in multiple validated water samples using the synthesized SNG-C/CB-PANI sensor device, obtaining excellent results of recovery values (97-104%). The synergetic effect of polyaniline and carbon black leads to novel antifouling and electrocatalytic effects that improve the applicability of this sensor in sample analysis versus complex conventional devices.

In Situ Synthesis of a Bismuth Vanadate/Molybdenum Disulfide Composite: An Electrochemical Tool for 3-Nitro-l-Tyrosine Analysis

The quantification of 3-nitro-l-tyrosine (NO₂-Tyr), an in vivo biomarker of nitrosative stress, is indispensable for the clinical intervention of various inflammatory disorders caused by nitrosative stress. By integrating the unique features of BiVO₄ and MoS₂ with matching bandgap energies, electrode materials with amplified response signals can be developed. In this regard, we introduce a hydrothermally synthesized bismuth vanadate sheathed molybdenum disulfide (MoS₂@BiVO₄) heterojunction as a highly sensitive electrode material for the determination of NO₂-Tyr. Excellent electrochemical behavior perceived for the MoS₂@BiVO₄ augments the performance of the sensor and allows the measurement of NO₂-Tyr in biological media without any time-consuming pretreatments. The synergistic interactions between BiVO₄ and MoS₂ heterojunctions contribute to low resistance charge transfer (R_ct = 159.13 Ω·cm²), a reduction potential E_pc = -0.58 V (vs Ag/AgCl), and a good response range (0.001-526.3 μM) with a lower limit of detection (0.94 nM) toward the detection of NO₂-Tyr. An improved active surface area, reduced charge recombination, and high analyte adsorption contribute to the high loading of the biomarker for improved selectivity (in the presence of 10 interfering compounds), operational stability (1000 s), and reproducibility (six various modified electrodes). The proposed sensor was successfully utilized for the real-time determination of NO₂-Tyr in water, urine, and saliva samples with good recovery values (±98.94-99.98%), ascertaining the reliability of the method. It is noteworthy that the electrochemical activity remains unaffected by other redox interferons, thus leading to targeted sensing applications.