In this study, NiO nanostructures were synthesized via a hydrothermal process using ascorbic acid as doping agent in the presence of ammonia. As prepared nanostructures were characterized using Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD), Brunauer-Emmett-Teller (BET) specific surface area analysis, and thermogravimetric analysis (TGA). These analyses showed that these nanostructures are in the form of cotton-like porous material and crystalline in nature. Furthermore, the average size of these NiO crystallites was estimated to be 3.8 nm. These nanostructures were investigated for their potential to be a highly sensitive and selective enzyme-free sensor for detection of urea after immobilizing on a glassy carbon electrode (GCE) using 0.1% Nafion as binder. The response of this as developed amperometric sensor was linear in the range of 100-1100 mu M urea with a R-2 value of 0.990 and limit of detection (LOD) of 10 mu M. The sensor responded negligibly to various interfering species including glucose, uric acid, and ascorbic acid. This sensor was applied successfully for determining urea in real water samples such as mineral water, tap water, and river water with acceptable recovery.

Funding Agencies|Deanship of Scientific Research group at King Saud University by Prolific Research Group [PRG-1437-30]

No abstract

This study involves environmentally friendly synthesis of copper nanoparticles in aqueous medium without inert gas protection, using ranolazine as a capping material. UV-Visible (UV-Vis) spectrometry showed that ranolazine-derived copper nanoparticles (Rano-Cu NPs) demonstrate a localized surface plasmon resonance (LSPR) band at 573 nm with brick-red color under optimized parameters, including pH, reaction time, and concentrations of copper salt, hydrazine hydrate, and ranolazine. The coating of ranolazine on the surface of Cu NPs was studied via Fourier transform infrared (FTIR) spectroscopy. Scanning electron microscopy (SEM) revealed that Rano-Cu NPs consist of spherical particles. X-ray diffraction (XRD) verified that Rano-Cu NPs are crystalline in nature. Atomic force microscopy (AFM) showed that the average size of Rano-Cu NPs was 40 ± 2 nm in the range of 22–95 nm. Rano-Cu NPs proved to be highly sensitive as a selective colorimetric sensor for As3+ via color change from brick red to dark green, in the linear range of 3.0 × 10−7 to 8.3 × 10−6 M, with an R² value of 0.9979. The developed sensor is simple, cost effective, highly sensitive, and extremely selective for As3+ detection, showing a low detection limit (LDL) of 1.6 × 10−8 M. The developed sensor was effectively tested for detection of As3+ in some water samples.

In this study, a simple, faster and eco-friendly method was used for the synthesis of piroxicam drug derived gold nanoparticles (PX-AuNPs) in aqueous solution. The electrochemical behavior of paracetamol (PAR) was investigated at a PX-AuNPs modified glassy carbon electrode (GCE) by using differential pulse voltrammetry (DPV) in Britton Robinson Buffer solution in strong acidic medium. It showed excellent electrocatalytic activity towards the anodic oxidation of PAR at the peak potential value of 0.66 V and considerable improvement in the peak currents as compared to that observed at the bare GCE. The advantages are related to the unique properties of modified nanosensor such as large surface area, catalytic behavior and hence increased electron transfer abilities compared to GC electrode. The calibration of peak current vs. concentration of PAR was linear in the range of 0.05–12 μM with correlation coefficient R2 = 0.996 and limit of detection (LOD) of 5 nM. We successfully applied this sensor for determination of PAR in drug samples with a mean recovery of 99.7%. The proposed sensor is simple, novel, rapid, reproducible and sensitive. It can be used as an alternative for chromatography and other voltammetric methods involving mercury electrode. The proposed method could be used for water analysis from pharmaceutical industrial effluents and so on.

No abstract