ZnO and SnO2-doped ZnO nanoparticles were prepared by a sol–gel method for the first time. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to characterize the ZnO and SnO2-doped ZnO samples. Advanced oxidation processes (AOPs) have proved very effective in treatment of the various hazardous organic pollutants such as surfactants and pharmaceuticals in water. The photocatalytic degradation of drug phenylephrine hydrochloride (PHE) was studied as model organic pollutant. Under UV exposure the process was investigated with ZnO and SnO2-doped ZnO. The degradation was studied under different conditions including irradiation time, pH, catalyst concentration, phenylephrine hydrochloride concentration and potassium peroxydisulfate as an oxidant. The experimental results indicated that maximum degradation (99.4±1.0%) of drug occurred with SnO2-doped ZnO catalyst. The results demonstrated that photodegradation efficiency of SnO2-doped ZnO was significantly higher than that of undoped ZnO. پرونده مقاله

In this study, the electrochemical determination of oxazepam in plasma samples was studied. The composite of graphene oxide/boron (B-RGO) was synthesized via the hydrothermal method and it was cast on the glassy carbon electrode (GCE). The polyaspartic acid (poly(ASP)) was deposited on the B-RGO by electropolymerization to prepare the modified electrode named B-RGO/ poly(ASP)|GCE. The B-RGO and B-RGO/poly ASP were characterized using scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). Electrochemical studies were performed by cyclic voltammetry (CV), linear sweep voltammetry (LSV) and differential pulse voltammetry (DPV) methods. The experimental parameters affecting the reduction of oxazepam such as pH, preconcentration time, scan rate and other analysis conditions, and instrumental parameters were optimized. Under the optimal conditions, the linear range was obtained from 0.001 to 800 μM with a correlation coefficient of 0.998. The repeatability of the method for the electrode to electrode and one electrode were 4.3% and 4.9%, respectively. The limit of detection (LOD) of 0.3 nM and the limit of quantitation (LOQ) of 1 nM were obtained. The high efficiency of the developed electrode in the determination of oxazepam in the plasma sample was proved by using acceptable results and satisfactory relative recovery percentage (>90%). Based on our calculation, the heterogeneous electron transfer rate constant (ks) was 1.92 s-1. The interaction between oxazepam and modifier was single-layer and multi-layer adsorption, respectively in low and high concentrations. پرونده مقاله