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61.
Filip Ciesielczyk Przemysław Bartczak Karolina Wieszczycka Katarzyna Siwińska-Stefańska Magdalena Nowacka Teofil Jesionowski 《Adsorption》2013,19(2-4):423-434
The aim of this work was to obtain an inorganic oxide system containing silica and magnesium oxide, and characterized by specific physicochemical properties, in particular well-defined adsorption parameters. The preparation process was carried out according to a co-precipitation method using solutions of sodium silicate and selected inorganic magnesium salt. The oxide system obtained (MgO·SiO2) was used as a support (adsorbent) of nickel(II) ions, whose precursors were model solutions of nitrates. The effectiveness of the adsorption process was evaluated using many different analytical techniques, including atomic absorption spectroscopy, energy dispersive X-ray spectroscopy and equivalent point titration. Moreover the stability of adsorbent/adsorbate bonding was estimated. The oxide systems—adsorbents—used in the process were also analyzed according to their physicochemical properties, especially changes in adsorption parameters. The last part of the study involved evaluation of the kinetics of the adsorption process depending on time and the pH of the reaction system. 相似文献
62.
Application of liquid chromatography/electrospray ionization ion trap tandem mass spectrometry for the evaluation of global nucleic acids: methylation in garden cress under exposure to CuO nanoparticles 下载免费PDF全文
63.
Vitamin B12 Phosphate Conjugation and Its Effect on Binding to the Human B12‐Binding Proteins Intrinsic Factor and Haptocorrin 下载免费PDF全文
Keith Ó Proinsias Michał Ociepa Katarzyna Pluta Mikołaj Chromiński Prof. Ebba Nexo Prof. Dorota Gryko 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(24):8282-8289
The binding of vitamin B12 derivatives to human B12 transporter proteins is strongly influenced by the type and site of modification of the cobalamin original structure. We have prepared the first cobalamin derivative modified at the phosphate moiety. The reaction conditions were fully optimized and its limitations examined. The resulting derivatives, particularly those bearing terminal alkyne and azide groups, were isolated and used in copper‐catalyzed alkyne–azide cycloaddition reactions (CuAAC). Their sensitivity towards light revealed their potential as photocleavable molecules. The binding abilities of selected derivatives were examined and compared with cyanocobalamin. The interaction of the alkylated derivatives with haptocorrin was less affected than the interaction with intrinsic factor. Furthermore, the configuration of the phosphate moiety was irrelevant to the binding process. 相似文献
64.
65.
Izabela Michalak Agnieszka Saeid Katarzyna Chojnacka 《Central European Journal of Chemistry》2013,11(2):313-319
In this study, the effect of the increase in the initial concentration of Na(I) ions in the solution during biosorption of Cr(III) ions by two edible algae: marine macroalga — Enteromorpha prolifera and microalga — Spirulina sp. was investigated. During biosorption, essential elements are exchanged with alkali and alkaline earth metal ions (e.g. Na(I) ions), which are naturally bound with the biomass. The goal of this study was to investigate the effect of the increase in concentration of Na(I) ions on biosorption performance. The equilibrium of the process is described by Langmuir equation. It was found that with the increase in the initial concentration of NaCl (from 132 to 7331 mg L?1), there was a lower biosorption capacity of Enteromorpha prolifera (from 85.8 to 51.0 mg g?1) and Spirulina sp. (74.2 to 20.7 mg g?1) towards Cr(III) ions. It was also possible to determine the number of times the solution used in the biosorption process can be recycled and yet mantain high biosorption capacity. The determined numbers were: 16 for Enteromorpha prolifera and 19 for Spirulina sp. 相似文献
66.
Urszula?KotowskaEmail author Katarzyna?Bieńczyk 《Central European Journal of Chemistry》2013,11(10):1634-1643
Direct immersion solid-phase microextraction has been optimized and applied to the simultaneous determination of the neutral and basic pharmaceuticals: caffeine, carbamazepine, clomipramine, chlorprothixene and clotrimazole at low concentrations in municipal wastewater. Two absorption type stationary phases: polydimethylsiloxane (PDMS) and polyacrylate (PA) have been found to be most effective for extraction of target analytes. The separation and detection were carried out by gas chromatograph coupled with mass spectrometer working in the selected ion monitoring mode. The method was validated for linearity, detection and quantitation limits, selectivity and precision. The average correlation coefficient of the calibration curves was 0.9933. The LOD values in influent and effluent wastewater were in the range of 10–145 ng L?1 and 4–111 ng L?1, respectively, which were a bit higher than those in the deionized water due to matrix effect. The high values of distribution coefficient (K fs ) in PDMS/water and PA/water systems (log K fs between 3.05 and 4.23) indicates the very high applicability of these stationary phases for determination of carbamazepine, clomipramine, chlorprothixene and clotrimazole in water samples.
相似文献
67.
Marzena Dabioch Robert Skorek Andrzej Kita Piotr Janoska Katarzyna Pytlakowska Piotr Zerzucha Rafal Sitko 《Central European Journal of Chemistry》2013,11(5):742-753
Elements that enter the aquatic environment may pose a health risk to wildlife and humans. The aims of this study were: to determine how the introduction of activated carbon for a water purification system will improve the quality of the water produced; and to investigate the sorption of metals on activated carbons, including determination of the accumulation, as well as changes in concentrations of elements in carbons. The tests were carried out on three types of activated carbons with different granular structure. All samples were collected from Water Treatment Plant Goczalkowice, Poland. Concentrations of elements were measured using an optical emission spectrometer with inductively coupled plasma. The experiment showed that metals accumulating in the activated carbons during the operation included: Ca, Mn, Zn, and Cu. In each of the three types of carbons, it can distinguish such elements as Ba, Al, Cr, Ni, Ti, which are characterized by irregular accumulation during the operation of the filter. The introduction of carbon sorbent for water treatment largely contributed to improvement in the quality of raw material supplied to customers, mainly with regard to taste and smell, as well as to reduction of basic parameters: color, absorbance in the UV range and oxidability. 相似文献
68.
Andrzej Okuniewski Jaroslaw Chojnacki Katarzyna Baranowska Barbara Becker 《Acta Crystallographica. Section C, Structural Chemistry》2013,69(2):195-198
Two new dialkylammonium thiosulfates, namely bis(diisopropylammonium) thiosulfate, 2C6H16N+·S2O32−, (I), and bis(tert‐butylammonium) thiosulfate, 2C4H12N+·S2O32−, (II), have been characterized. The secondary ammonium salt (I) crystallizes with Z = 4, while the primary ammonium salt (II), with more hydrogen‐bond donors, crystallizes with Z = 8 and a noncrystallographic centre of inversion. In both salts, the organic cations and thiosulfate anions are linked within extensive N—H...O and N—H...S hydrogen‐bond networks, forming extended two‐dimensional layers. Layers are parallel to (10) in (I) and to (002) in (II), and have a polar interior and a nonpolar hydrocarbon exterior. The layered structure and hydrogen‐bond motifs observed in (I) and (II) are similar to those in related ammonium sulfates. 相似文献
69.
Mirosław Giurg Katarzyna Piekielska Magdalena Gębala Bartosz Ditkowski Marcin Wolański Wanda Peczyńska‐Czoch 《合成通讯》2013,43(11):1779-1789
The catalytic oxidative cyclocondensation of the o‐aminophenols 1a–f was investigated. The oxidants used were air/laccase, H2O2/horseradish peroxidase, H2O2/ebselen (3), and TBHP/diphenyl diselenide 4. The products obtained were 2‐amino‐3H‐phenoxazin‐3‐one—questiomycin A, its derivative 2b, and cinnabarinic acid and actinocin (2c,d). Substrates with methyl groups at 4 and 5 positions of benzene ring were converted to different dihydrophenoxazinones 2g,h. Compounds having chlorine atoms at the same positions underwent oxidation to planar phenoxa-zinones 2e,f with elimination of one hydrochloride molecule. 相似文献
70.
Herein we report a facile synthesis of esters of bis‐α‐aminoalkylphosphinic acids obtained by an addition of Cbz‐protected phosphinic analogues of amino acid methyl esters to an appropriate imine in refluxing benzene. Complete deprotection of the esters could be achieved in one step by the action of 30% HBr in acetic acid. 相似文献