Hierarchical 3D Snowflake-like Iron Diselenide: A Robust Electrocatalyst for Furaltadone Detection.

An electrocatalyst with a large active site is critical for the development of a high-performance electrochemical sensor. This work demonstrates the fabrication of an iron diselenide (FeSe2)-modified screen-printed carbon electrode (SPCE) for the electrochemical determination of furaltadone (FLD). It has been prepared by the facile method and systematically characterized with various microscopic/spectroscopic approaches. Due to advantageous physiochemical properties, the FeSe2/SPCE showed a low charge-transfer resistance value of 200 Ω in 5.0 mM [Fe(CN)6]3-/4- containing 0.1 M KCl. More importantly, the FeSe2/SPCE exhibited superior catalytic performance compared to the bare SPCE for FLD sensing based on the electrochemical response in terms of a peak potential of -0.44 V (vs Ag/AgCl (sat. KCl)) and cathodic response current of -22.8 µA. Operating at optimal conditions, the FeSe2-modified electrode showed wide linearity from 0.01 to 252.2 µM with a limit of detection of 0.002 µM and sensitivity of 1.15 µA µM-1 cm-2. The analytical performance of the FeSe2-based platform is significantly higher than many previously reported FLD electrochemical sensors. Furthermore, the FeSe2/SPCE also has a promising platform for FLD detection with high sensitivity, good selectivity, excellent stability, and robust reproducibility. Thus, the finding above shows that the FeSe2/SPCE is a highly suitable candidate for the electrochemical determination of glucose levels for real-time applications such as in human urine and river water samples.

Rationally designed f-MWCNT-coated bismuth molybdate (f-MWCNT@BMO) nanocomposites for the voltammetric detection of biomolecule dopamine in biological samples.

Selective and sensitive dopamine (DPA) sensor was developed using hydrothermally prepared functionalized multi-walled carbon nanotube-coated bismuth molybdate (f-MWCNT@BMO). The f-MWCNT@BMO-reinforced electrode exhibited an outstanding electrocatalytic activity towards DPA oxidation. The nanocomposite-reinforced electrode displayed a rapid response towards DPA sensing and possessed the minimized potential of (Epa + 0.285 V vs Ag/AgCl) in 0.1 M phosphate buffer (PB). The electrochemical results of prepared sensors were analyzed using the differential pulse voltammetry method (DPV). As a result, the f-MWCNT@BMO-reinforced electrode exhibited a widelinear range of 10 nM - 814 µM with a very low detection limit of 3.4 nM towards DPA oxidation. The developed sensor shows excellent selectivity in presence of similar functional group biomolecules. The detection of DPA in real samples was evaluated in human serum, as the results of the proposed sensor possessed good recoveries.

Electrocatalytic evaluation of graphene oxide warped tetragonal t-lanthanum vanadate (GO@LaVO4) nanocomposites for the voltammetric detection of antifungal and antiprotozoal drug (clioquinol).

Metastable and rarely reported GO warped tetragonal phase t-lanthanum vanadate nanocomposites (GO@LaVO4-NCs) are reported for the sensitive electrochemical determination of antifungal drug Clioquinol (CQ). The hydrothermal method was adopted for synthesis of GO@LaVO4-NCs. The electrochemical performance of CQ was examined using cyclic voltammetry (CV) and differential plus voltammetry (DPV) at GO@LaVO4-NCs modified glassy carbon electrode (GCE). The electrocatalytic oxidation of CQ at the GO@LaVO4-NCs/GCE shows the highest anodic peak current at a potential of +0.51 V vs. Ag/AgCl. The proposed sensor provides excellent sensitivity of 4.1894 µA µM-1 cm-2, a very low detection limit (LOD) of 2.44 nM, and a wide range of 25 nM to 438.52 µM towards CQ detection. Finally, the detection of CQ in biological media was successfully done using the GO@LaVO4-NCs/GCE and possesses recoveries of 94.67-98.0%.

An eco-friendly low-temperature synthetic approach towards micro-pebble-structured GO@SrTiO3 nanocomposites for the detection of 2,4,6-trichlorophenol in environmental samples.

The low-temperature synthesis of the graphene oxide-wrapped perovskite-type strontium titanate nanocomposites (GO@SrTiO3-NC) is reported for the electrochemical sensing of organochlorine pesticide 2,4,6-trichlorophenol (TCP) detection. The as-prepared GO@SrTiO3 nanocomposites provide a large surface area, excellent conductivity, and active sites, which are more favorable to the catalysis of TCP. The synergistic effect between the GO and the perovskite SrTiO3 results in the extended working range of 0.01 to 1.47 and 1.47 to 434.4 µM with a very low detection limit of 3.21 nM towards TCP detection. Moreover, the prepared sensor possessed good selectivity and long-term stability. Finally, the practical applicability of the sensor was tested in environmental samples of river water and soil, exhibiting adequate recovery values.

An Ultra-Sensitive Electrochemical Sensor for the Detection of Carcinogen Oxidative Stress 4-Nitroquinoline N-Oxide in Biologic Matrices Based on Hierarchical Spinel Structured NiCo2O4 and NiCo2S4; A Comparative Study.

Various factors leads to cancer; among them oxidative damage is believed to play an important role. Moreover, it is important to identify a method to detect the oxidative damage. Recently, electrochemical sensors have been considered as the one of the most important techniques to detect DNA damage, owing to its rapid detection. However, electrode materials play an important role in the properties of electrochemical sensor. Currently, researchers have aimed to develop novel electrode materials for low-level detection of biomarkers. Herein, we report the facile hydrothermal synthesis of NiCo2O4 micro flowers (MFs) and NiCo2S4 micro spheres (Ms) and evaluate their electrochemical properties for the detection of carcinogen-causing biomarker 4-nitroquinoline n-oxide (4-NQO) in human blood serum and saliva samples. Moreover, as-prepared composites were fabricated on a glass carbon electrode (GCE), and its electrochemical activities for the determination of 4-NQO were investigated by using various electrochemical techniques. Fascinatingly, the NiCo2S4-Ms showed a very low detection limit of 2.29 nM and a wider range of 0.005 to 596.64 µM for detecting 4-NQO. Finally, the practical applicability of NiCo2S4-Ms in the 4-NQO spiked human blood serum and saliva samples were also investigated.

Bifunctional bimetallic heterojunction material based on Al2O3/ZnO micro flowers for electrochemical sensing and catalysis.

We report the synthesis, characterization, electrochemical sensing and catalytic capability of the bimetallic heterojunction Al2O3/ZnO micro flowers (AZ MFs). In order to prepare this bifunctional material, the facile hydrothermal process was adopted. The material was thoroughly characterized for the crystal structure and morphology with Powder XRD, XPS and FE-SEM. The investigation of electrochemical sensing was done using hydroquinone (HQ) and the chemical catalysis was using rhodamine B (RhB) with our bimetallic Al2O3/ZnO micro flowers as these are harmful industrial pollutants. The process parameters like the influence of scan rate and pH was efficiently optimized for the electrochemical detection of HQ and kinetics for the time dependent catalytic degradation of RhB dye. The linear relationship between the peak current and the concentration of HQ was found to be in the range of 0.125-20.25 µM with an impressive detection limit of 11.2 nM. In the chemical catalytic degradation of the RhB dye, our bimetallic material thrived well during the reaction and degraded the material in 10 min. The performance of bimetallic Al2O3/ZnO micro flowers towards HQ detection and RhB degradation shows good stability, reproducibility and it can be efficiently utilized to treat the environmental pollutants.

One-step synthesis of reduced graphene oxide sheathed zinc oxide nanoclusters for the trace level detection of bisphenol A in tissue papers.

After a long-term toxicity study on Bisphenol A (BPA), the European Union and U.S food and drug administration updating the rules regarding the usage of BPA by extending the prohibition of BPA to include in the production of papers, on February 2018. Therefore, it is essential to establish the trace level BPA detectors in paper samples. In this report, the synthesis of novel ZnO nanoclusters wrapped with reduced graphene oxide (ZnO NCs/rGO) and its application towards the selective electrocatalytic detection of BPA are described. Initially, ZnO NCs/rGO is synthesized by the one-step hydrothermal approach, and various characterizations explain the compound's compositions and structure. The significance of ZnO NCs/rGO together with good electrocatalytic properties leads this material to the platform for electrochemical sensor. Finally, ZnO NCs/rGO was fabricated and validated as an effective sensor for the sensitive detection of BPA. The demonstrated sensor revealed excellent detection of BPA with the very low detection limit (2.1 nM), and also it offered good analytical parameters with more extensive linear range and higher sensitivity. Likewise, the sensor annexes good durability, reproducibility, and selectivity towards the determination of BPA. Due to the nourishing capacity of the prepared ZnO NCs/rGO, it is employed for the detection of BPA in tissue paper samples.

In-situ growth of MOF-derived Co3S4@MoS2 heterostructured electrocatalyst for the detection of furazolidone.

The over-exploitation of antibiotics in food and farming industries ruined the environmental and human health. Consequently, electrochemical sensors offer significant advantages in monitoring these compounds with high accuracy. Herein, MOF-derived hollow Co3S4@MoS2 (CS@MS) heterostructure has been prepared hydrothermally and applied to fabricate an electrochemical sensor to monitor nitrofuran class antibiotic drug. Various spectroscopic methodologies have been employed to elucidate the structural and morphological information. Our prepared electrocatalyst has better electrocatalytic performance than bare and other modified glassy carbon electrodes (GCE). Our CS@MS/GCE sensor exhibited a highly sensitive detection by offering a low limit of detection, good sensitivity, repeatability, reproducibility, and stability results. In addition, our sensor has shown a good selectivity towards the target analyte among other potential interferons. The practical reliability of the sensor was measured by analyzing various real-time environmental and biological samples and obtaining good recovery values. From the results, our fabricated CS@MS could be an active electrocatalyst material for an efficient electrochemical sensing application.

Enhancing catalytic activity through the construction of praseodymium tungstate decorated on hierarchical three-dimensional porous biocarbon for determination of furazolidone in aquatic samples.

Boosting catalytic performance as a vital role for an electrochemical sensor for monitoring various hazardous nitro drugs. Herein, an inexpensive, facile, and eco-friendly construction of praseodymium tungstate decorated on three dimensional porous biocarbon (PrW/3D-PBC) for electrochemical determination of carcinogenic residue furazolidone (FZ). The nanostructured PrW nanoparticles were prepared by solvent evaporation from peroxo-tungstic acid and 3D-PBC was prepared from biomass precursor under the carbonization method. Furthermore, the composite of PrW decorated on 3D-PBC was prepared by an ultrasonic-assisted wet chemical approach. Besides, the composite characterization of crystalline, functional group, degree of carbonization, chemical states, and morphology were utilized by theXRD, FTIR, RAMAN, XPS, and FESEM analysis. These 3D porous carbon decorated PrW nanoparticles facilitate the electrochemical anchoring sites, surface area, and ease of diffusion layers towards the detection of hazardous nitro pollutant FZ by using CV analysis. The low LOD and high sensitivity were achieved by FZ determination through using LSV and DPV techniques. The practical capability of the PrW/3D-PBC/GCE sensor was determined by using aquatic samples to achieve a good recovery result. These results instigate that the PrW/3D-PBC will be an efficient electrocatalytic material for FZ sensor in environmental aquatic samples.

In-situ formation of niobium oxide - Niobium carbide - Reduced graphene oxide ternary nanocomposite as an electrochemical sensor for sensitive detection of anticancer drug methotrexate.

Engineering the nanostructure of an electrocatalyst is crucial in developing a high-performance electrochemical sensor. This work exhibits the hydrothermal followed by annealing synthesis of niobium oxide/niobium carbide/reduced graphene oxide (NbO/NbC/rGO) ternary nanocomposite. The oval-shaped NbO/NbC nanoparticles cover the surface of rGO evenly, and the rGO nanosheets are interlinked to produce a micro-flower-like architecture. The NbO/NbC/rGO nanocomposite-modified electrode is presented here for the first time for the rapid and sensitive electrochemical detection of the anticancer drug methotrexate (MTX). Down-sized NbO/NbC nanoparticles and rGO's high surface area provide many active sites with a rapid electron transfer rate, making them ideal for MTX detection. In comparison to previously reported MTX sensors, the developed drug sensor exhibits a lower oxidation potential and a higher peak current responsiveness. The constructed sensors worked analytically well under optimal conditions, as shown by a low detection limit of 1.6 nM, a broad linear range of 0.1-850 µM, and significant recovery findings (∼98 %, (n = 3)) in real samples analysis. Thus, NbO/NbC/rGO nanocomposite material for high-performance electrochemical applications seems promising.

Fabrication of a New Electrochemical Sensor Based on Bimetal Oxide for the Detection of Furazolidone in Biological Samples.

This study utilized a simple hydrothermal method to synthesize nickel molybdenum oxide (NMO) for the detection of furazolidone (FZE). Our synthesized NMO was characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), field emission scanning electron spectroscopy (FE-SEM), and energy dispersive X-ray spectroscopy (EDX). The cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were used to detect the FZE. Under optimized conditions, the obtained results showed that the NMO had an excellent electrocatalytic property towards FZE. As a result, NMO/GCE showed a good linear range of 0.001-1765 µM, an excellent detection limit (LOD) of 0.02 µM, and sensitivity of 0.2042 µA µM-1 cm-2.

Synthesis of nickel-doped ceria nanospheres for in situ profiling of Warfarin sodium in biological media.

Venous thromboembolism is one of the major disorders, which is significantly increased the mortality and morbidity rate. Warfarin sodium (WFS) is the most extensively prescribed drug for the prevention of thromboembolic diseases however, it has a narrow therapeutic index. Recently, many methods for detecting and monitoring the level of WFS have been proposed. However, the electrochemical method has gained more interest than the other traditional method due to its ease of operation. This article describes the hydrothermal synthesis of nickel-doped cerium oxide (CeO2@Ni) nanospheres for the selective electrochemical determination of WFS. Various spectroscopic techniques have been used to analyze the chemical composition, and surface morphology of CeO2@Ni nanospheres. Further, the prepared CeO2@Ni nanospheres modified electrode demonstrated excellent electrocatalytic behavior for WFS detection, with an ultralow detection limit of 6.3 × 10-9 M, a linear range of 1.0 × 10-8 M to 1.51 × 10-4 M and 1.51 × 10-4 M to 9.51 × 10-4 M, and a higher sensitivity of 2.9986 µA µM-1 cm2. Therefore, we believe that the CeO2@Ni nanosphere electrocatalyst can serve as a potential electrode catalyst for the sensing of WFS in real-time applications.

Rational synthesis of rare-earth lanthanum molybdate covered reduced graphene oxide nanocomposites for the voltammetric detection of Moxifloxacin hydrochloride.

Recently, perovskite structure-based metal oxide nanomaterials and their composites opted for electrocatalyst because of its excellent conductivity, unique, and favored electronic structure. In this attempt, herein we prepared the rare earth mixed metal molybdate covered reduced graphene oxide La2(MoO4)3@rGO nanocomposites by a simple hydrothermal method for the sensitive detection of Moxifloxacin hydrochloride (MOF) in pharmaceutical and human urine samples. The various physicochemical analysis such as SEM, TEM, XRD and Raman spectroscopy confirms the successful formation of (La2(MoO4)3@rGO) nanocomposites. Furthermore, the electroanalytical performance of La2(MoO4)3@rGO modified glassy carbon electrode (La2(MoO4)3@rGO/GCE) was analyzed using the cyclic voltammetry (CV) and differential pulse voltammetry (DPV) which shows excellent results with a wide range of 1.0 × 10-8 M to 6.0 × 10-4 M and the detection limit of 2.84 × 10-9 M towards the MOF detection. Furthermore, the developed sensor expressed good selectivity, repeatability, stability and reproducibility. Finally, the real sample analysis of the developed sensor was tested in the MOF tablets and human urine samples, which shows the appreciable recoveries.

Se substituted 2D-gC3N4 modified disposable screen-printed carbon electrode substrate: A bifunctional nano-catalyst for electrochemical and absorption study of hazardous fungicide.

The indispensable usage of pesticides for the control and prevention of pests is probable and includes several types based on the problems in the crops. Among them, fungicides, are one problem-solving agent curing fungal developments. the disproportionate use of fungicides will lead to environmental deterioration and several health issues. The assessment of such fungicides is highly motivated to be detected. Under the class of two-dimensional materials, graphitic carbon nitride (GCN) with high surface area and high electrocatalytic activity was chosen as electrode material. The efficiency of GCN was improved with the subsequent substitution of selenium (Se) into the triazine ring as Se-GCN. The structural and surface analysis was done and the layered structure was proved. The electrochemical detection of CBM showed a lower detection limit at 6 nM with a linear range 0.099 µM-346.9 µM while, the absorption studies showed a LOD of 20 nM with a linear range of 0.099 µM-182.09 µM. The orange juice and vegetable extract samples had good recovery with CBM at Se-GCN modified disposable screen-printed electrode. The developed disposable electrode was more sensitive with 6.45 µAµM-1cm2 sensitivity and highly reactive with CBM. Moreover, the developed sensor will be more effective in sensing applications to avoid the menace generated by several agents.

Tailored architecture of molybdenum carbide/iron oxide micro flowers with graphitic carbon nitride: An electrochemical platform for nano-level detection of organophosphate pesticide in food samples.

Herein we report the ternary hybrid nanocomposite of iron oxide @ molybdenum carbide micro flowers decorated graphitic-carbon nitride (Fe3O4@MoC MFs/g-CN), as a catalyst for the detection of organophosphorus pesticide, parathion (PAT), for the first time. The growth of hierarchical nanostructure from the core level will facilitate easy diffusion of analyte and interact more effectively with the reactive catalytic sites. Thus, Fe3O4 NFs architecture was hydrothermally grown over MoC flakes from the core level, which further hybridized with g-CN to ensure electrical conductivity and mechanical stability. Experimental results demonstrate that Fe3O4@MoC MFs/g-CN/GCE has superior catalytic efficacy for PAT reduction. At optimum conditions, the proposed sensor exhibits a low detection limit (7.8 nM), high sensitivity, and wide linear range (0.5-600 µM) toward PAT detection. The satisfactory test results of the food samples indicate that the Fe3O4@MoC MFs/g-CN/GCE sensor can be used as an excellent candidate for real-time PAT detection.

A sonochemical assisted synthesis of hollow sphere structured tin (IV) oxide on graphene oxide sheets for the low-level detection of environmental pollutant mercury in biological samples and foodstuffs.

In modern approaches for nanomaterials synthesis, ultrasonication plays an important role in providing the larger surface area and smaller crystalline size properties that are favorable to electrochemical techniques. Herein, we report the tin (IV) oxide on graphene oxide nanoparticles were synthesized (SnO2@GO NPs) by ultrasonic methodology (UZ SONOPULS HD 3400 Ultrasonic homogenizer) with the total power of 400 W and the (frequency of 20 kHz; 140 W/dm3). The formation of as-prepared SnO2@GO NPs and its surface morphology were scrutinized over XRD, XPS, TEM, and FESEM. Besides, the sonochemically prepared SnO2@GO NPs were employed for the determination of environmental hazardous mercury (Hg). As a result, the modified electrode acquired a very low-level detection limit of 1.2 nM with a wider range of 0.01-10.41-µM and 14.52-225.4-µM for the detection of Hg. Finally, the practical applicability of SnO2@GO NPs in spiked human blood serum and tuna fish samples shows appreciable found and recovery values. .

Sonochemically recovered silver oxide nanoparticles from the wastewater of photo film processing units as an electrode material for supercapacitor and sensing of 2, 4, 6-trichlorophenol in agricultural soil samples.

The present work describes the sensing application and supercapacitive behavior of silver oxide nanoparticles recovered from wastewater of photo film processing units via one-pot green sonochemical recovery process. The recovered silver oxide nanoparticles (Ag2O NPs) were characterized by spectral techniques such as FT-IR, Raman, UV-Vis and analytical tools such as XRD, FE-SEM, TEM, EDX, XPS and BET. In view of Ag2O NPs as electrode material with wide technological applications, the recovered Ag2O NPs were examined for their sensing and supercapacitive behavior. The developed sensor was explored to detect 2, 4, 6-trichlorophenol, and as expected it shows moral parameters which are required of an effective sensor. Therefore, it was exploited for the quantification of 2, 4, 6-trichlorophenol in soil samples from the agricultural area. Cyclic voltammetric (CV), Galvanostatic Charge-Discharge (GCD) and Electrochemical Impedance Spectroscopic (EIS) studies on the recovered Ag2O NPs coated Ni foam electrode depicted the pronounced capacitive behavior. The GCD studies revealed an enhanced electrochemical performance, particularly with the large specific capacitance of 530 F/g at a current density of 1 A/g. The cyclic stability of the electrode material was identified with 88% retention in specific capacitance even after 5000 GCD cycles. These results strongly proved that the recovered Ag2O NPs are potential candidates for sensing and supercapacitor applications.

A novel approach to iron oxide separation from e-waste and bisphenol A detection in thermal paper receipts using recovered nanocomposites.

To promote sustainability, the effective reutilization of electronic waste and profitable recovery of valuable materials from e-scrap are essential. A recent report showed that 500 million printer cartridges enter landfill annually, creating immense interest in establishing a facile recovery method for transforming waste toner into a ferrous resource. Furthermore, the European Union and US Food and Drug Administration have published guidelines concerning bisphenol A (BPA) use in the manufacture of thermal paper receipts. Accordingly, in this study, BPA levels in thermal receipts collected from various stores in Taiwan were detected by glassy carbon electrodes fabricated using graphene oxide-recovered Fe3O4 nanocomposites.

One-pot synthesis of three-dimensional Mn3O4 microcubes for high-level sensitive detection of head and neck cancer drug nimorazole.

We described a three-dimensional Mn3O4 microcubes (3D-Mn3O4MCs) synthesised via a facile hydrothermal route for the determination of nimorazole (NMZ), an important drug that used in the treatment of head and neck cancer. The 3D-Mn3O4 MCs possess large active area and high conductivity, and 3D-Mn3O4 MCs film modified screen-printed carbon electrode (3D-Mn3O4MCs/SPCE) was fabricated which displayed excellent electrocatalytic ability towards NMZ. Under optimised working conditions, the modified electrode responded linearly to NMZ in the 0.025-8060µM concentration range and the detection limit was 6nM. A rapid, sensitive, selective, reproducible, and durable sensor was described. The practical feasibility of the sensor was demonstrated in human serum and NMZ tablet samples. The obtained results revealed the potential real-time applicability of the sensing device in biological analysis and pharmaceutical formulations.