Fabrication, characterization and exploration of cobalt (II) ion doped, modified zinc oxide thick film sensor for gas sensing characteristics of some pernicious gases

Highly electroactive Co-ZnO/GO nanocomposite: Electrochemical sensing platform for oxytetracycline determination

Antimicrobial residues in animal-derived foods have become a major source of concern around the world. Oxytetracycline (OTC), one of these antibiotics that belongs to the tetracycline family should be detected in these matrices. Nanostructured metal oxides have attracted a lot of scientific attention due to their special characteristics that can be exploited for creating innovative nanodevices. Therefore, in the present study, we report the fabrication of cobalt-doped ZnO/GO nanocomposites for OTC sensors using a simple and environmentally friendly method that does not require toxic solvents. Contact angle measurements, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and UV-Vis were used to confirm the successful fabrication of the Co-ZnO/GO nanocomposite and to determine the surface area, Structural, morphological features, chemical composition and purity of the nanocomposite. The electrochemical and electrocatalytic properties were recorded using cyclic voltammetry (CV), electrochemical impedance spectroscopy, and differential pulse voltammetry (DPV). Optimizing parameters such as scan rate, pH value, deposition time, and deposition potential, we achieve a wide linear concentration range from 10-12 M to 10-7 M, with an impressive detection limit of 1.6 10-13 M.Notably, our sensor exhibits remarkable selectivity, demonstrating its usefulness for the detection of oxytetracycline traces in real milk samples. These results emphasize the novelty and practical significance of our work and provide a promising avenue for the development of sensitive and selective electrochemical sensing platforms in various fields.

Atropine-Phosphotungestate Polymeric-Based Metal Oxide Nanoparticles for Potentiometric Detection in Pharmaceutical Dosage Forms

The new research presents highly conductive polymeric membranes with a large surface area to volume ratio of metal oxide nanoparticles that were used to determine atropine sulfate (AT) in commercial dosage forms. In sensing and biosensing applications, the nanomaterials zinc oxide (ZnONPs) and magnesium oxide (MgONPs) were employed as boosting potential electroactive materials. The electroactive atropine phosphotungstate (AT-PT) was created by combining atropine sulfate and phosphotungstic acid (PTA) and mixing it with polymeric polyvinyl chloride (PVC) with the plasticizer o-nitrophenyl octyl ether (o-NPOE). The modified sensors AT-PT-ZnONPs or AT-PT-MgONPs showed excellent selectivity and sensitivity for the measurements of atropine with a linear concentration range of 6.0 × 10⁻⁸ − 1.0 × 10⁻³ and 8.0 × 10⁻⁸ − 1.0 × 10⁻³ mol L⁻¹ with regression equations of E_(mV) = (56 ± 0.5) log [AT] − 294 and E_(mV) = (54 ± 0.5) log [AT] − 422 for AT-PT-NPs or AT-PT-MgONPs sensors, respectively. The AT-PT coated wire sensor, on the other hand, showed a Nernstian response at 4.0 × 10⁻⁶ − 1.0 × 10⁻³ mol L⁻¹ and a regression equation E_(mV) = (52.1 ± 0.2) log [AT] + 198. The methodology-recommended guidelines were used to validate the suggested modified potentiometric systems against various criteria.