جستجوی مقالات مرتبط با کلیدواژه « nio nanoparticles » در نشریات گروه « شیمی »

In this work, thioridazine (TR) as an important neuroleptic drug has been detected simply by an electrochemical approach using a glassy carbon electrode modified by nickel oxide nanoparticles decorated graphene quantum dot (NiO/GQD/GCE). The bare and modified electrodes were characterized using the scanning electron microscope (SEM) and electrochemical techniques. The cyclic voltammetric studies demonstrated that the NiO/GQD/GCE has remarkably enhanced electro-catalytic activity towards the oxidation of TR in neutral solutions. The results (significant increase in peak current and a negative shift in TR oxidation potential) are related to the increase in electrode surface area and electron transfer rate along with the modifier catalytic role. The NiO/GQD modified electrode used for sensitive determination of TR by differential pulse voltammetry (DPV) method. The effect of experimental parameters on the obtained results was studied and optimized. The NiO/GQD/GCE modified electrode revealed a linear response in the concentration range from 2×10-9 to 200×10-9 M with a limit of detection (LOD) equal to 0.05×10-9 M (S/N=3). The sensor was applied to determine TR in serum and pharmaceutical samples, which proves this sensor is an ideal device for TR determination.

A chemically modified electrode was prepared by incorporating NiO/graphene oxide nanocomposite into graphite screen printed electrode (NiO/GO/SPE) to determine levodopa. Cyclic voltammetry, differential pulse voltammetry and chronoamperometry were used to investigate the electrochemical behavior of levodopa at the chemically modified electrode. According to the results, NiO/GO/SPE showed high electrocatalytic activity for levodopa oxidation, producing a sharp oxidation peak current at about 240 mV vs Ag/AgCl reference electrode at pH 7.0. The peak current was linearly dependent on levodopa concentration over the range of 0.8–700.0 µM with the detection limit (3σ) of 0.2 µM. The proposed method was successfully applied as a rapid, highly selective, simple, and precise one to determine levodopa in biological fluids.

The effect of NiO nanoparticles on the rheological and volumetric properties of dilute solutions of starch-NaOH-H2O, PEG400-PEG2000 and PEG400-PEG6000 were investigated. Achieve this aim requires to prepare the stable nanofluids. Therefore, nanoparticles of NiO were added to these solutions and dispersed by a shaker and an ultrasonic bath for making the homogeneous nanofluids. The UV-Vis spectroscopy, zeta potential and dynamic light scattering have been used to specify the stability and particle size distribution of colloidal solutions studied. Fluid flow and suspense structure of NiO nanoparticles in the solutions of starch-NaOH-H2O, PEG400-PEG2000 and PEG400-PEG6000 were studied by measuring the magnetorheological properties at T=298.15 K. Bingham plastic, Herschel-Bulkley and Carreau-Yasuda models have been applied for modeling the magnetorheological properties of nanofluids. Density values of NiO-starch-NaOH-H2O, NiO-PEG400-PEG2000 and NiO-PEG400-PEG6000 nanofluids have also been measured at T = (298.15, 308.15 and 318.15) K. The excess molar volumes were calculated from the density data for highlighting the interparticle interactions occurred in nanofluids. Singh et al. equation was used for fitting the excess molar volume values.

A carbon paste electrode modified with NiO nanoparticles (CPE-M-NiO/NPs) was fabricated and used as a high performance sensor for nitrite (NT). CPE-M-NiO/NPs was prepared by mixing NiO/NPs, graphite powder and liquid paraffin together. The CPE-M-NiO/NPs showed electrocatalytic activity to the electro-oxidation of NT, and an irreversible oxidation peak appeared at 0.90 V with improved peak current. The linear response range was found to be 0.8–1100 μM. Detection limit (3σ) of NT was found to be 0.3 μM by square wave voltammetry (SWV) method. The CPE-M-NiO/NPs was successfully applied for the determination of NT in food samples.