A sonochemical assisted preparation of zirconium dioxide (ZrO ₂ ) sheathed reduced graphene oxide (ZrO ₂ @rGO NCs) nanocomposites as the highly sensitive electrode material for the detection of oxidative stress biomarker 3-Nitro-l-tyrosine (3-NT) was reported. The formation of prepared ZrO ₂ @rGO NCs and its surface morphology were scrutinized by the X-ray photoelectron spectroscopy (XPS) and Field emission scanning electron microscope (FE-SEM). Moreover, the as-prepared nanocomposites were fabricated on the glassy carbon electrode (GCE), and its electrochemical performance towards the detection of 3-NT are studied by the various electrochemical techniques such as Electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), and amperometric ( i -t). The excellent conductivity of the rGO and the electrocatalytic properties of the ZrO ₂ significantly improves the electrochemical performances. As a result, the ZrO ₂ @rGO NCs display the LOD of 9 nM with the covering range of 0.025 to 855.2 μ M towards the detection of 3-NT. Finally, the real-time practicability of ZrO ₂ @rGO NCs in the spiked human serum and saliva samples also investigated, which shows the feasible found and recoveries. Hence, this study sonochemically prepared ZrO ₂ @rGO NCs provides the simple, rapid and efficient towards the detection of 3-NT in biological samples.

In this study, we have prepared anatase titanium (IV) oxide warped reduced graphene oxide nanocomposites (TiO ₂ -rGO NC) using ultrasonic methodology. The morphology of the TiO ₂ -rGO NC was studied using FESEM and TEM. In addition, XRD, Raman, thermogravimetric analysis (TGA) and XPS are used to analyze the crystallinity and chemical composition of the TiO ₂ -rGO NC. We have also investigated the electrochemical behavior of the as-prepared NCs with electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), and different pulse voltammetry techniques (DPV). The TiO ₂ -rGO NC modified electrode shows the lower charge transfer resistance (R _ct ) of 62.87 Ω. Next, the glassy carbon electrode (GCE) was modified with sonochemically prepared TiO ₂ -rGO NC and used to determine the electrocatalytic reduction of nitrofurazone (NTF). Thus, the proposed sensor established the wider covering range (WCR) of 0.01 to 380 µ M and an excellent detection limit of 2.28 nM. Finally, the TiO ₂ -rGO NC/GCE was applied to determine the NTF in real samples, including crayfish and human blood serum samples, which acquired good found and recovery values.

The p-n junction (Ni/Zn)O and its reduced graphene oxide nanocomposites ((Ni/Zn)O@rGO) has been synthesized through the hydrothermal method and used for effective electrochemical determination analgesic drug acetaminophen (AAP). In addition, the XRD characteristic peak and Raman modes confirm the formation of a p-n junction (Ni/Zn)O@rGO nanocomposites. The morphology of the as-prepared nanocomposites exposes nano-sized spherical particles that were well decorated on the rGO sheets, which results in a larger surface area. Further, the incorporation rGO and (Ni/Zn)O induced the catalytic properties and electrochemical performance. The electrochemical characterization of AAP was investigated at ((Ni/Zn)O@rGO/GCE) glass carbon electrode and differential pulse voltammetry (DPV) were adopted for the quantitative analysis of AAP. As a result, the prepared nanocomposite possessed great sensitivity, selectivity and stability. Further, the prepared sensor shows the wider linear range of 0.009–0.096 μ M and 0.096–413 μ M with a very low detection limit of 2.2 nM. Moreover, the practical applicability of the prepared sensor was tested in the pharmaceutical and human urine samples. Also, the developed method would widen the application of nanocomposites materials in the fabrications of more novel electrochemical sensing platforms.

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.

In this study, a molybdenum-doped copper oxide (Mo–CuO) composite was synthesized via a hydrothermal method and combined with carbon black (CB) to form Mo–CuO@CB. This composite was used to modify a screen-printed carbon electrode (SPCE) for the detection of Metol (MT), an industrial pollutant harmful to both human health and the environment. Structural and surface characterization was performed using high-resolution transmission electron microscopy, field-effect scanning electron microscopy, energy-dispersive spectroscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, and X-ray diffraction. Electrochemical techniques, including differential pulse voltammetry and cyclic voltammetry, were used to assess the sensor’s performance. The Mo–CuO@CB@SPCE sensor exhibited a low detection limit of 2.7 nM, and limit of quantification is 82 nM, a broad linear range (5.0 × 10⁻⁹–170 mol L⁻¹), and high sensitivity (4.148 μA μM⁻¹ cm⁻²), benefiting from the catalytic activity of Mo–CuO and the large surface area of CB. With recovery rates ranging from 96% to 100.6% in pond, river, and tap water, the sensor effectively detects MT in environmental samples, ensuring reliable monitoring of this persistent pollutant.