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A rapid and sensitive, non-enzymatic electrochemical detection of hydrogen peroxide (H2O2) is of utmost importance for diagnosis and treatment of related diseases in clinical purpose. To meet this requirement, we report a simple and robust microwave-assisted synthetical route via prepared Gd2O3 nanoparticles decorated reduced graphene oxide nanocomposite (Gd2O3 NPs@RGO) modified electrode for non-enzymatic H2O2 detection. The composition and morphological formation were characterized by using XRD, FT-IR, XPS, FESEM, and HRTEM. The impedance and cyclic voltammetry exhibit tremendous electrocatalytic capability and superior performance toward H2O2 reduction. A sensitive and reproducible amperometric H2O2 sensor was fabricated which was able to detect concentration as low as 1.57 nM. The method worked well even in clinical and biological samples, which indicates the reliability of the method in real time analysis.

In this work, Bi3.64Mo0.36O6.55/Bi3.84W0.16O6.24 (BMW1) and Bi2MoO6/Bi2WO6 (BMW2) nanocomposite were successfully prepared by a facile hydrothermal method with different PH. The Synthesis of good crystallization BMW1 and BMW2 with nanoparticles and nanosheet-like morphology is revealed from XRD, SEM, TEM and XPS, respectively. The BMW1 and BMW2 nanocomposite affords an excellent structural stability and fast electron and ion transportation compared with pure Bi2Mo6 and Bi3.64Mo0.36O6.55, which can beneficial for improving the electrochemical performance. The pseudocapacitive behaviour of nanocomposite is analyzed by cyclic voltammetry (CV), chronopotentiometry (CP) and AC impendence in the 1 M KOH electrolyte. The as-prepared materials specific capacitance reaches to 1056 F g−1 and 699 F g−1 at 1 A g−1, respectively. Moreover, the as-prepared nanocomposite exhibits high cycle stability, and 80% of its initial capacitance is retained after continuous 3000 cycles. Especially, the higher electrochemical performance of BMW1 compared with BMW2, which is possibly ascribed to the higher Bi content. These results demonstrated nanocomposite and high Bi content materials might be a promising electrode material for pseudocapacitor.

In this work, we describe a facile fabrication of silver nanoparticles decorated on porous ultrathin two dimensional (2D) graphitic carbon nitride nanosheets (AgNPs@g-CN) via chemical approach, which was characterized by various analytical techniques including cyclic voltammetry (CV), differential pulse voltammetry (DPV) and chronoamperometry. As expected, the AgNPs@g-CN modified glassy carbon electrode (AgNPs@g-CN/GCE) exhibited remarkable electrocatalytic activity towards the detection of quercetin (QCR) with a wide linear range from 1.0 × 10−8 to 1.2 × 10−4 mol L−1 and a lower detection limit of 6.0 × 10−9 mol L−1. Besides, the amperometric results revealed that the peak current for QCR could not affect upon the sequential additions of electroactive interfering species such as metal ions (300 μM), biomolecules (100 μM), and other flavonoids (50 μM) indicating the selectivity of the proposed sensor. Moreover, the AgNPs@g-CN modified electrode displayed higher stability and reproducibility towards the detection of QCR. The AgNPs@g-CN/GCE could also be used to detect QCR in green apple (GA) samples with satisfactory recoveries for practical applications. The concepts behind the novel architecture to modify electrodes can be potentially harnessed in other electrochemical sensors and photocatalysis applications.

Herein, the synthesis of novel non-aggregated spinel nickel ferrite, NiFe2O4 nanosheets (NiFe2O4 NSs) and its application towards the selective electrocatalytic reduction of hydrogen peroxide are described. Initially, NiFe2O4 NSs is synthesized by one-step hydrothermal approach, and numerous characterizations deliberately explain the compound's composition and structure. Finally, the NiFe2O4 NSs underwent direct non-enzymatic electrochemistry and succeeded, it as mimicking Horseradish Peroxidase properties. The significance of non-aggregated NiFe2O4 NSs together with good electrocatalytic properties leads the material to the platform for electrochemical sensors. Moreover, NiFe2O4 NSs is fabricated and validated as an enzyme-free biosensor for the sensitive detection of H2O2. The demonstrated sensor revealed excellent detection of H2O2 with the pico-molar detection limit (12.4 pM), and also it offered good analytical parameters with more extensive linear range and higher sensitivity. Likewise, the non-enzymatic biosensor annexes good durability, reproducibility, and selectivity towards the determination of H2O2. Due to the nourishing capacity of the prepared NiFe2O4 NSs, it is employed for the enzyme-free detection of H2O2 in human blood and rat brain serum samples.

The anticancer flutamide (FLU) is derived from the starting compounds of environmental pollutant 4-nitroaniline (4-NA), thereby, simultaneous electrochemical determination of FLU and 4-NA has offered the onsite monitoring of both starting and end product in pharmaceutical formulations. This work reports the simultaneous electrochemical determination of FLU and 4-NA based on FeVO4/LaVO4 electrode material. The FeVO4/LaVO4 composite is prepared by the sonochemical route and characterized by XRD, Raman, XPS, and HRTEM analysis. The FeVO4/LaVO4 shows a single crystalline nature and forms stable crystal structures with uniform distributions. The electroanalytical performances of FeVO4/LaVO4/GCE for simultaneous determination of FLU and 4-NA were done by differential pulse voltammetry (DPV) techniques. The studies have shown a low LOD of 1.3 nM for 4-NA and 2.9 nM for FLU. Furthermore, it reveals good sensitivity of about 1.85 and 1.25 µA µM−1 cm−2 for 4-NA and FLU respectively. The FeVO4/LaVO4/GCE showed high selectivity with the other potential interfering compounds.

Hydrogen peroxide (H2O2) is a renowned industrial oxidant that plays a significant role in cell biology, and pathogenesis. On this note, we propose a simple Zinc Manganese Oxide (ZnMn2O4; ZMO) based H2O2 sensor for rapid in-situ tracking and determination of H2O2 from live cells, and bio-samples. The ZMO catalyst have been synthesized via simple scalable protocol; surface morphology, elemental composition, electronic states, crystallinity, and other physiochemical properties are studied and discussed in-detail using various spectroscopic tools. The ZMO modified electrode displays an excellent electrochemical activity toward H2O2 sensing with a wide dynamic range (20 nM-10 mM), low detection limit (8.3 nM), excellent selectivity, reproducibility, operational stability, and rapid response time (

Electrochemically reduced graphene oxide wrapped copper nanoparticles (ERGO/Cu NPs) composite were successfully synthesized through cyclic voltammetry. Highly stable, enhanced electroactive CuNPs growth was optimized by using different electrolyte solutions for deposition such as aqueous 0.1 M H3BO3 (I), 0.1 M H2SO4 (II) and 0.1 M Na2SO4 (III) containing 0.05 M CuSO4. Furtherly, electrocatalytic activity of the as prepared electrodes (I, II, III) were studied by non-enzymatic glucose oxidation. Obviously, lower over potential of glucose oxidation was noticed at ERGO/Cu NPs (I) modified electrode with amplified anodic current response compared than that of other electrodes (II, III). Then, ERGO/CuNPs (I) composite was characterized by SEM, FESEM, EDAX, XRD, Raman spectroscopy and cyclic voltammetry. In addition, ERGO/Cu NPs (I) modified electrode possess excellent electrocatalytic performance towards glucose in terms of wide linear range from 0.14 μM to 5091 mM and lower limit of detection (LOD) 49 nM. Moreover, the fabricated sensor exhibits appreciable reproducibility, good stability and excellent selectivity. Furthermore, obtained real sample recovery results declare that the architecture sensor matrix could be a suitable platform for detection of glucose in human samples.

In this work, a cost-effective, simple and scalable synthesis of nanostructured magnesium cobalt oxide (MgCo2O4) was presented by various methods. The structural morphology was evaluated by powder X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), Raman, Fourier-transform infrared spectrometry (FTIR), and X-ray photoelectron spectroscopy (XPS). Further, electrochemical measurements by electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), and differential pulse voltammetry (DPV) revealed that the MgCo2O4-modified electrode showed good sensitivity (0.895 µA µM−1 cm−2), a wide linear range (0.5–1415.8 μM) and a relatively low detection limit (0.047 μM) towards the electrochemical determination of thioridazine (TZ, antipsychotic drug). Loading catalyst, pH, scan rate, and peak potential of TZ were optimized. The proposed sensor features excellent anti-interference ability, good cyclic stability, high reproducibility, and repeatability. The system has also been successfully applied for the detection of TZ in blood serum samples.

In recent years, most people affected by neurotransmitters and amino acid-related diseases, which cause more disorders in the human brain and body. And hence monitoring the trace level of neurotransmitters and amino acids is necessary. Nowadays transition bimetallic oxides (TBMO’s) play a vital role in sensing application due to their unique physical, electrical, and chemical properties. As the carbon-based materials, importantly graphene aerogel (GA) have a high surface area to enhance the conductivity of the electrode material. Here, we reported a molybdenum tungsten oxide nanowire intercalated graphene aerogel (Mo-W-O/GA) nanocomposite-based sensor for the simultaneous detection of dopamine (DA) and tyrosine (Tyr). The proposed Mo-W-O/GA nanocomposite was prepared by two steps, facile hydrothermal and freeze-drying method. The formation of the nanocomposite was verified by various spectroscopic techniques. The resulting Mo-W-O/GA/GCE could be used for the quick and sensitive simultaneous determination of DA and Tyr in the presence of other bio interfering compounds. The Mo-W-O/GA sensor exhibited maximum performance toward DA and Tyr under optimum conditions. The sensor parameter such as linear range and lower detection limit (LOD) of Mo-W-O/GA/GCE for the determination of DA was 0.001–448.0 μM and 0.8 nM respectively, and for the determination Try a linear range of 0.001–478.0 µM and LOD of 1.4 nM was obtained. The newly proposed sensor was used for precise sensing of DA and Tyr in human urine and blood serum samples with good satisfactory recoveries.

The construction of mixed metal oxides matrix acts as highly active electrode materials in the field of an electrochemical sensor, owing to high conductivity, a large number of active sites, fast kinetics, and superior sensing activity. In this study, the spherical-like NiO@Gd2O3 (NGO) microstructures were successfully synthesized by a simple co-precipitation method and employed for the selective electrochemical detection of thioridazine hydrochloride (TRH). The as-prepared NGO-500 material was confirmed with suitable spectrometric techniques such as X-ray diffraction (XRD), Fourier transform infrared (FT-IR), Raman spectroscopy, Brunauer–Emmett–Teller (BET) method, field emission scanning electron microscope (FE-SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectrometry (XPS) analyses. The electrocatalytic performance of TRH on modified screen-printed carbon electrode (NGO-500/SPCE) was investigated through cyclic voltammetric (CV), and differential pulse voltammetric (DPV) methods. As a result, the proposed electrode demonstrated a wide linear response of 0.04–151.6 µM, a low detection limit of 0.004 µM with an excellent sensitivity of 3.09 µA µM−1 cm−2. Besides, the modified electrode establishes outstanding selectivity in the presence of the various interfering compounds towards TRH detection. The fabricated electrode displayed notable repeatability, reproducibility, acceptable cyclic and storage stability. The feasibility of the NGO-500 electrode was used to sense TRH in urine and serum samples with satisfactory results.