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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 μM and 0.096-413 μM 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. [ABSTRACT FROM AUTHOR]

A high-performance imipramine (IMPR) sensor has been developed based on metal chalcogenide-carbon composite materials. The antimony telluride-graphite nanofiber (Sb2Te3-GNF, hereafter SBT-GNF) composite was synthesized by the hydrothermal method and confirmed by X-ray powder diffraction (XRD) pattern. The morphology, crystalline lattice, and chemical states were characterized by HRTEM, SAED, and XPS analysis. The characterizations confirmed the formation of an effective composite, SBT-GNF. The SBT-GNF was fabricated as a disposable sensor electrode with a screen-printed carbon electrode (SPCE) and examined for the detection of IMPR by differential pulse voltammetry (DPV). The electroanalytical results of SBT-GNF are compared with the SBT and GNF, and the rational design of effective composite is discussed. SBT-GNF/SPCE showed a good linear range (0.01‑51.8 μM), sensitivity (1.35 ± 0.1 μA μM−1 cm−2), and low LOD (4 ± 2 nM). Moreover, the SBT-GNF/SPCE revealed high selectivity and high tolerance limit against potential interfering compounds in blood serum and urine samples. Therefore, this electrochemical sensor can be applicable for the detection of tricyclic antidepressant drug IMPR in clinical and pharmaceutical analysis. [ABSTRACT FROM AUTHOR]

In this study, we have prepared anatase titanium (IV) oxide warped reduced graphene oxide nanocomposites (TiO2-rGO NC) using ultrasonic methodology. The morphology of the TiO2-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 TiO2-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 TiO2-rGO NC modified electrode shows the lower charge transfer resistance (Rct) of 62.87 Ω. Next, the glassy carbon electrode (GCE) was modified with sonochemically prepared TiO2-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 µM and an excellent detection limit of 2.28 nM. Finally, the TiO2-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. [ABSTRACT FROM AUTHOR]

A new type of manganese diselenide nanoparticles (MnSeNPs) was synthesized by using a hydrothermal method. Their surface morphology, crystallinity and elemental distribution were characterized by using transmission electron microscopy, X-ray diffraction, energy dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy which scrutinize the formation of the NPs. The NPs were coated on a glassy carbon electrode (GCE), and electrochemical impedance spectroscopy, cyclic voltammetry and differential pulse voltammetry were applied to study the electroanalytical properties towards the oxidation of the food additive capsaicin. The modified GCE displays lower charge transfer resistance (Rct = 29.52 Ω), a larger active surface area (0.089 cm2/g, and more efficient electrochemical oxidation of capsaicin compared to a MnS2/GCE and a bare GCE. The oxidation peak potential is 0.43 V (vs. Ag/AgCl) which is lower than that of previously reported GCEs. The sensor has a detection limit as low as 0.05 μM and an electrochemical sensitivity of 2.41 μA μM−1 cm−2. The method was applied to the determination of capsaicin in pepper samples.Electrochemical determination of capsaicin in pepper extract by using MnSeNPs modified electrode. [ABSTRACT FROM AUTHOR]