24 (2018) Scientific papers, Series A
Permanentní URI k tomuto záznamuhttps://hdl.handle.net/10195/71954
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Článek Otevřený přístup peer-reviewedpostprint Measurement of bidirectional reflectance distribution function on custom-made gonio-spectrophotometer(2018) Janíček, Petr; Schützová, Eliška; Panák, Ondrej; Sole, Aditya Suneel; Nussbaum, PeterThis article presents a new series of measurements of printed samples on custom-made gonio-spectrophotometer and the respective evaluation by bidirectional reflectance distribution function. A set of three different papers (matt, glossy, and metallic) printed with six primary spot colours, together with Spectralon, were measured. Dependence of bidirectional reflectance distribution function on the reflection zenith angle, as well as its spectral representation, is presented. The results obtained are discussed regarding the ability of the custom-made setup to determine glossy and colour components of the studied set of samples. Three methods of calculation of reflectance for a fixed geometry are applied and the CIELAB colorimetric coordinates derived to compare with CIELAB values obtained by a commercially available spectrophotometer.Článek Otevřený přístup peer-reviewedpublished Voltammetric determination of trinitrotoluene (TNT) at antimony-modified glassy carbon paste electrode in polluted soil sample collected in an industrial area(University of Pardubice, 2018) Švancara, Ivan; Dellingerová-Perinajová, Barbora; Sopha, Hanna Ingrid2,4,6-trinitrotoluene (TNT) in polluted soil sampled in the area of a factory producing industrial explosives could be determined using an antimony film pre-plated ex-situ onto a glassy carbon paste electrode (SbF-GCPE) in combination with square-wave cathodic stripping voltammetry (SWCSV). For electrochemical measurements in Britton-Robinson buffer (BRB, pH 9), the substance of interest had to be transferred from solid sample into the solution by extracting with aqueous or water / methanolic media of chosen composition and adjusted pH, in some cases, followed by neutralising the extracts with solid NaHCO3. A comparison of the results from analyses of four different solutions has allowed us to evaluate the most effective extracting agent, which was the case of a mixture of 0.5 M CH3COOH in 30% CH3OH neutralised with solid NaHCO3, and further diluted with BRB (pH 9) in order to yield pH ~ 8. In this medium, the SWCSV analysis with SbF-GCPE has resulted in the content of 3.77 μg TNT in 10 mL extract, which corresponded to the same contents in mg per 1 kg of dried soil. This has represented ca. 85% recovery with the result obtained with GC-MS, which can still be considered as acceptable agreement.Článek Otevřený přístup peer-reviewedpublished Adsorptive stripping voltammetry of vitamin D3 at glassy carbon electrode(University of Pardubice, 2018) Nallbani, Arlinda; Farag, Amir Shaaban; Vytřas, Karel; Sýs, MilanAdsorptive stripping voltammetry (AdSV) of cholecalciferol at the glassy carbon electrode (GCE) was developed and based on existing conventional approaches employing anodic oxidation in pure organic electrolytes or aqueous-organic mixtures. Despite a rather poor reproducibility of the adsorption-driven process (with the RSD of ca. 10 %), significantly higher sensitivity was achieved. As optimum conditions, the respective procedure comprised an accumulation of cholecalciferol from 40% ethanol at 300 min–1 for 8 min followed by electrochemical detection in the Britton-Robinson buffer (pH 4.0) using square-wave voltammetry at a potential step of 5 mV, amplitude of 35 mV, and frequency of 40 HzČlánek Otevřený přístup peer-reviewedpublished Determination of caffeine and glucose in selected energy drinks(University of Pardubice, 2018) Pravcová, Kateřina; Sýs, Milan; Vytřas, Karel; Česlová, LenkaThe aim of this study was to monitor the caffeine and glucose content in several energy drinks. The caffeine was determined by (direct) differential pulse voltammetry at a glassy carbon paste electrode in 0.5 mol L–1 sulfuric acid at a potential step of 5 mV, potential amplitude of 40 mV, and the scan rate of 50 mV s–1. The content of glucose was determined using amperometric glucose biosensor in 0.1 mol L–1 phosphate (pH 7.0) buffer solution at a constant voltage of +0.4 V and stirring speed of 400 min–1. The selected samples were analysed and the results obtained compared to those declared by manufactures. Except to three samples, namely "Monster", "Red Bull" (without sugar) and "Spark", the individual results were in good agreement with the declared amounts. Moreover, based on the analyses performed, it can be stated that the energy drinks "Big Shock!" and "Red Bull" are the best source of energy when considering the found total sugar via the glucose content.Článek Otevřený přístup peer-reviewedpublished Determination of hyaluronic acid in pharmaceutical products by spectrophotometry and HPLC coupled to fluorescence or mass spectrometric detection(University of Pardubice, 2018) Kašparová, Jitka; Arnoldová, Kamila; Korecká, Lucie; Česlová, LenkaIn a daily basis, the pharmaceutic and cosmetic industry makes effort in advertising their products with a promise to avoid diseases or health problems. Among one of the most popular substances is nowadays, without doubts, hyaluronic acid (HA). Due to its natural origin allowing its biodegradability and non-toxicity, HA is widely used as a component of joint supplements or as a substance ensuring moisturizing properties. Here, interest is focused on the determination of hyaluronic acid in commonly available non-prescription products using different analytical techniques followed by comparison of the determined content with that declared by manufacturers.Článek Otevřený přístup peer-reviewedpublished Preparation of hyaluronan nanoparticles using different cross-linking strategies(University of Pardubice, 2018) Kašparová, Jitka; Korecká, Lucie; Bílková, Zuzana; Palarčík, Jiří; Lierová, Anna; Šinkorová, Zuzana; Česlová, LenkaNowadays, the use of drug-delivery systems becomes more and more popular. The use of the supporting medium for drug substances may serve to delay and control the drug release. Biodegradable polymers, such as hyaluronic acid (HA), represent the most natural materials beneficially used for such systems. In this work, we focused on the preparation of hyaluronic acid nanoparticles using low-molecular weight HA (LMW-HA; 11 and 30 kDa) which is rarely used because the size of the obtained particles is usually higher than those of the high-molecular weight form. To verify the suitability of LMW-HA for the preparation of nano-scale particles, different cross-linking strategies were chosen. The hydrodynamic diameters of prepared nanoparticles and the structure compactness were then compared. Adipic acid dihydrazide was used as a conventional cross-linker which leads to monodisperse nanoparticles (186 nm, 255 nm resp.) and compact structure. The use of bis(3-aminopropyl)amine as a novel approach for covalent cross-linking of HA results in the particles with higher hydrodynamic diameters (592 nm, 317 nm resp.) and with less compact structure. Both strategies were then combined with a goal to reduce the hydrodynamic diameters to the nanoscale format and tighter structure. The results obtained has shown a slight improvement (208 nm, 286 nm resp.), but with negligible effect on the structure of particles.Článek Otevřený přístup peer-reviewedpublished Extraction of quercetin and rutin from fortified spreadable processed cheese(University of Pardubice, 2018) Červenka, Libor; Švecová, Blanka; Salek, Richardos Nicolaos; Buňka, FrantišekA functional spreadable processed cheese (SPC) containing quercetin or rutin was produced by melting the ingredients at 85 °C for 2 min, and the retention rate of both flavonoids and antioxidant activity of the SPC samples assessed. Ultrasound-assisted extraction of quercetin and rutin from SPC to methanol (99.9% and 50%, v/v) for 30 min, respectively, was found to be optimal extraction procedure. Whereas a high recovery rate (92 %) for quercetin was achieved, only 64 % of rutin was recovered from the SPC sample. The results have indicated that rutin was thermally unstable during the melting process. SPC with quercetin or rutin exhibited effective radical-scavenging activity and possessed strong ferric reducing antioxidant potential. These results suggest that spreadable processed cheese may serve as the functional product.Článek Otevřený přístup peer-reviewedpublished Investigation of an amphoteric behaviour of arsenic dopant in polycrystalline SnSe(University of Pardubice, 2018) Navrátil, Jiří; Šraitrová, Kateřina; Kucek, Vladimír; Plecháček, Tomáš; Kašparová, Jana; Drašar, ČestmírWe investigated eventual amphoteric behaviour of As atoms in SnSe by substituting in either cation or anion site. The investigation involved two series of polycrystalline samples of nominal composition Sn1-xAsxSe (0 ≤ x ≤ 0.1) and SnAsxSe1-x (0 ≤ x ≤ 0.08). The prepared powders were identified by X-ray diffraction. Hot-pressed from powder, polycrystalline pellets were used for characterization of transport and thermoelectric properties in temperature range of 300–730 K. An embedding of the As atoms in either cation or anion site seems to prevent formation of the major defects present in the undoped SnSe, tin vacancies VSn2-. Instead, selenium vacancies VSe2+ together with substitutional defects AsSn+ play the major role in the electronic transport in the Sn1-xAsxSe system. Due to rather low solubility of arsenic in the system (x ≤ 0.02), either As inclusions or amorphous As-Se phase is formed in highly doped samples. In the case of SnAsxSe1-x, As atoms enter Se position forming AsSe-, which increases the hole concentration in the doped samples at lower temperatures. At higher temperatures, the properties of the compounds (for x ≤ 0.03) are influenced by the formation of highly conductive AsSn phase. Generally, the substitution of As for both anion and cation lead to no evident enhancement of the thermoelectric figure of merit ZT.Článek Otevřený přístup peer-reviewedpublished Odd-numbered fatty acids in type 2 diabetes mellitus(University of Pardubice, 2018) Janeček, Radim; Špryncová, Martina; Čegan, AlexanderThis work deals with the study of lipid metabolism in type 2 diabetics focusing on the changes in odd-numbered fatty acid concentrations. Diabetes mellitus is a syndrome of metabolic disorders in which the concentration of insulin and its secretion are impaired. It indicates an impaired metabolism of glucose, lipids, and proteins. The main goal of this work was to measure concentrations of odd-numbered fatty acids (ONFA) in healthy individuals and in patients with type 2 diabetes mellitus and to compare the concentrations between both groups by using statistical methods. Plasma samples were deproteinized and lipids were extracted into organic solvents. Thin layer chromatography was used to separate 5 lipid fractions. All the lipid fractions were derivatized into fatty acid methyl esters and analyzed by a gas chromatograph. ONFA are minor group of the fatty acids and their concentrations are lower in type 2 diabetes mellitus. The most significant changes in concentrations were registered for tridecanoic and pentadecanoic acid.Článek Otevřený přístup peer-reviewedpublished Different approaches for preparation of AuNPs-based conjugates as a signal-generating unit for electrochemical biosensors(University of Pardubice, 2018) Murasová, Pavla; Kovářová, Aneta; Srbová, Jana; Bílková, ZuzanaWith the advent of micro- and nanotechnology, major advances and breakthroughs have taken place in many areas, such as biotechnology, medicine, pharmacy or material industry. Gold nanoparticles (AuNPs) with their unique optical and physical properties as well as biocompatibility have already proved themselves to be powerful tool in biological applications. In this work, AuNPs were selected as a potential electrochemically active label. With the aim to use them as an electrochemical active tag, two types of AuNPs were tested and suitable protocols for their functionalization were optimized. Non-functionalized AuNPs were modified with thiolated DNA oligonucleotides using Au-S bond. Such conjugates could be potentionally used as a DNA probe. Functionalized AuNPs containing carboxyl groups were also modified, but with specific antibodies. In this case, the goal was to optimize suitable protocol for effective modification performed with carbodiimide crosslinker enabling direct and covalent immobilization. Finally, quality of AuNPs-IgG was defined by experiments via detection of bacterial cells in model samples.