20 (2014) Scientific papers, Series A
Permanentní URI k tomuto záznamuhttps://hdl.handle.net/10195/75412
Procházet
2 výsledky
Search Results
Článekpeer-reviewedpublished Otevřený přístup Sensitive voltammetric method for determination of chemotherapeutic drug methotrexate using liquid mercury free silver solid amalgam electrode(University of Pardubice, 2014) Bandžuchová, Lenka; Šelešovská, Renáta; Chýlková, JaromíraVoltammetric behaviour of a wide-spread used chemotherapeutic drug methotrexate (MTX) was investigated on a polished silver solid amalgam electrode (p-AgSAE) employing various voltammetric methods like cyclic voltammetry, direct current voltammetry and differential pulse voltammetry. It was found that MTX provided two reduction and one oxidation peak in an acidic medium, and the positively situated reduction signal (Ep = –340 mV), due its favorable analytical properties, was studied more in detail. 0.05 mol l–1 acetate buffer of pH 5 was selected as an optimum medium for monitoring of the MTX reduction on p-AgSAE. Operating parameters of differential pulse voltammetry were optimized and proposed voltammetric method provided high repeatability (relative standard deviation of 11 repeated measurements at concentration level of methotrexate of 1×10–7 mol l–1 equaled to 1.7 %), linear concentration range from 5×10–10 to 3×10–6 mol l–1 and low limit of detection (LD = 1.5×10–10 mol l–1). The applicability of proposed method was verified by analysis of real sample of chemotherapeutic preparation.Článekpeer-reviewedpublished Otevřený přístup Evaluation of structural and charge properties of polyamide nanofiltration membrane(University of Pardubice, 2014) GHERASIM, CRISTINA VERONICA; Mikulášek, Petr; Chýlková, Jaromíra; Krejčová, AnnaNanofiltration (NF) is a highly efficient membrane separation process which has various environmental and industrial applications. Nanofiltration membranes are finely porous membranes with specific interesting features, their characterization being important for understanding of the NF processes and for their prediction for practical use. A polyamide thin-film composite NF membrane (AFC 80) was characterized in the present work by two different techniques: modelling of the rejection of uncharged solutes and modelling of the salt rejection. The interpretation of the data from uncharged solutes rejection experiments by using Donnan steric partitioning pore model (DSPM) allows to determine the structural characteristics of the AFC 80 membrane, i.e., effective pore radius (rp), and thickness to porosity ratio ()x/Ak). The experimental data for sodium chloride rejection were used to calculate the effective fixed charge density (MX) by means of an irreversible thermodynamics model (Spiegler–Kedem model) and of a charge model, namely Teorell–Meyer–Sievers (TMS) model. It was found that the membrane charge depends on the salt concentration in solution, this behaviour being attributed to ion adsorption on the membrane. The dependence of the charge density on NaCl concentration obeys a Freundlich isotherm equation.