RESUMEN
Objectives: The aim of this study is to study the electroactivity of zoledronic acid (ZOL), optimize the parameters affecting voltametric analysis of ZOL, and make a comparison between voltametric methods used to assay ZOL. Materials and Methods: Three voltametric methods, cyclic voltammetry (CV), square wave voltammetry (SWV), and differential pulse voltammetry (DPV), were used to determine the concentrations of ZOL solutions (0.25-1.2 mg.mL-1). Britton-Robinson universal buffer solutions (BRB) were used as supporting electrolytes with a glassy carbon working electrode. Results: The calibration plots were linear in the range from 0.20 to 1.2 mg.mL-1 for differential DPV and CV and from 0.09 to 1.2 mg.mL-1 for SWV. DPV showed the highest correlation coefficient R2 value of 0.993 and the lowest limit of detection (LOD) of 37.2 µg.mL-1. Furthermore, DPV exhibited the highest precision with the lowest relative standard deviations (RSD) values. For a commercial product of ZOL, DPV showed the best accuracy and precision with 102.32% recovery and 2.88% RSD. Conclusion: ZOL is an electroactive compound. The pH of the BRB supporting the electrolyte is important for ZOL electroactivity. DPV is the recommended method for voltametric analysis of ZOL because of its high-performance regarding accuracy, precision, and LOD compared with other studied methods.
RESUMEN
In the present work TiO2 nanotubes (TNT) have been synthesized by alkaline hydrothermal transformation. Then they have been doped with Gd element. Characterizations of doped and undoped TNT have been done with TEM and SEM. The chemical composition was analyzed by EDX, Raman and FTIR spectroscopy. The crystal structure was characterized by XRD. Carbon paste electrode has been fabricated and mixed with Gd doped and undoped TNT to form a nanocomposite working electrode. Comparison of bare carbon paste electrode and Gd doped and undoped TNT carbon paste electrode for 1.0 ×10-3 M K4 [Fe(CN)6] voltammetric analysis; it was observed that Gd doped TNT modified electrode has advantage of high sensitivity. Gd doped TNT modified electrode has been used as working electrode for itopride assay in a pharmaceutical formulation. Cyclic voltammetry analysis showed high correlation coefficient of 0.9973 for itopride (0.04-0.2 mg/mL) with a limit of detection (LOD) and limit of quantitation values (LOQ) of 2.9 and 23.0 µg.mL-1 respectively.
RESUMEN
The application of the powdered biomass of Zygophyllum coccineum plants for the removal of Pb and Cu ions from water has been investigated. Energy-dispersive X-ray analysis and Fourier-transform infrared characterization revealed the presence of functional groups related to various components of the biomass. Surface area analyses and scanning electron microscopy demonstrated the nonporous and low surface area nature of the powdered biomass. The contact times required for Pb and Cu ion removal to reach equilibrium were 60 and 45 min, respectively. The optimum pH for the highest percentage of removal was 4. In 50 mL Cu ion solution (50 ppm), 0.2 g of powdered biomass was sufficient for Cu ion removal, while at similar concentrations, Pb ion removal increased significantly with the increase in the biomass. The best particle size for the removal of both ions was 0.212-0.50 mm. Pb ion removal was found to correlate with the Langmuir model, while Cu correlated with the Freundlich model. Langmuir isothermal model revealed adsorption capacities of 25.5 and 14.8 mg g-1 for Pb and Cu ions, respectively. This study shows that Z. coccineum biomass is efficient in removing Pb and Cu from water.