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121.
Cihan Topcu Gamze Lacin Vedat Yilmaz Fatih Coldur Bulent Caglar Osman Cubuk 《Analytical letters》2018,51(12):1890-1910
A novel copper(II)-selective electrode based on graphite oxide/imprinted polymer composite was developed for the electrochemical monitoring of copper(II) (Cu2+) ions. The electrode exhibited highly selective potentiometric response to Cu2+ with respect to common alkaline, alkaline earth and heavy metal cations. The composite composition studies indicated that the most suitable composite composition performing the most promising potentiometric properties was 20.0% ionophore (Cu2+-ion imprinted polymer), 10.0% paraffin oil, 5.0% multiwalled carbon nanotubes, and 65.0% graphite oxide. The fabricated electrode exhibited a linear response to Cu2+ over the concentration range of 1.0?×?10??6–1.0?×?10??1?M (correlation coefficient of 0.9998) with a sensitivity of 26.1?±?0.9?mV decade??1. The detection limit of the fabricated electrode was determined to be 4.0?×?10??7?M. The electrode worked well in the pH range of 4.0–8.0. The electrode had stable, reversible and fast potentiometric response (3?s). In addition, the electrode had a lifetime of more than 1 year. The analytical applications of the proposed electrode were performed using as an indicator electrode for the potentiometric titration of Cu2+ with ethylene diamine tetraacetic acid solution and for the determination of Cu2+ of spiked river, dam, and tap water samples. The obtained results for potentiometric titration and water samples were satisfactory. 相似文献
122.
İsmail Yener Mustafa Abdullah Yilmaz Özge Tokul Ölmez Pelin Köseoğlu Yılmaz Yeter Yeşil 《Analytical letters》2019,52(7):1031-1049
The Euphorbiaceae family comprises of about 300 genera and 5000 species primarily distributed in America and tropical Africa. The Euphorbia genus is represented by 105 species and locally named as “Sütle?en” and “Xa?îl” in Turkey. The present study aimed to determine the chemical constituents of E. aleppica, E. eriophora, E. macroclada, E. grisophylla, E. seguieriana subsp. seguieriana, E. craspedia, E. denticulata, E. falcata, and E. fistulosa, and classify them by utilizing the chemometric techniques of principal component analysis (PCA) and hierarchical cluster analysis (HCA). Linoleic acid, 17-tetratriacontane, palmitic acid, and hexatriacontane were the major fatty acids from the gas chromatography–mass spectrometry (GC/MS) analyses. Characterization of 268 constituents of the studied species was achieved by liquid chromatography–ion trap–time-of-flight–mass spectrometry (LC-IT-TOF-MS). Furthermore, a new liquid chromatography–tandem mass spectrometry (LC-MS/MS) method was developed and validated for the simultaneous quantitative determination of 11 compounds (quinic acid, protocatechuic acid, rutin, hesperidin, eugenol, p-coumaric acid, piceatannol, scopoletin, dl-kavain, chrysophanic acid, and resiniferatoxin) in these species. The developed method was validated for the linearity, limit of detection, limit of quantification, repeatability, and recovery. 相似文献
123.
124.
Nuriye Kocak Mustafa Sahin Ilker Akin Mahmut Kus Mustafa Yilmaz 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(10):776-779
Chitosan nanoparticles (CHN) were prepared based on ionotropic gelation between low moleculer weight chitosan and sodium tripolyphosphate (TPP) under microwave irradiation. Particle size, zeta potential, and FT-IR techniques were used for characterization of CHN. The influence of reaction time on the nanoparticle size distribution was investigated, and the results showed that the microwave irradiation method evidently decreases the reaction times and particle size over the conventional method. It was determined by the results of the zeta potential measurements that synthesized CHN under microwave irradiation clearly exhibits more homogeneous and stable dispersion. 相似文献
125.
Yonca Alkan Goksu Gorkem Yilmaz Yusuf Yagci 《Journal of polymer science. Part A, Polymer chemistry》2019,57(24):2387-2395
A versatile strategy for the preparation of end‐functional polymers and block copolymers by radical exchange reactions is described. For this purpose, first polystyrene with 2,2,6,6‐tetramethylpiperidine‐1‐oxyl end group (PS‐TEMPO) is prepared by nitroxide‐mediated radical polymerization (NMRP). In the subsequent step, these polymers are heated to 130 °C in the presence of independently prepared TEMPO derivatives bearing hydroxyl, azide and carboxylic acid functionalities, and polymers such as poly(ethylene glycol) (TEMPO‐PEG) and poly(ε‐caprolactone) (TEMPO‐PCL). Due to the simultaneous radical generation and reversible termination of the polymer radical, TEMPO moiety on polystyrene is replaced to form the corresponding end‐functional polymers and block copolymers. The intermediates and final polymers are characterized by 1H NMR, UV, IR, and GPC measurements. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019 , 57, 2387–2395 相似文献
126.
Ahmet Kilic Mahmut Ulusoy Mustafa Durgun Zeynep Tasci Ismail Yilmaz Bekir Cetinkaya 《应用有机金属化学》2010,24(6):446-453
Based on the a ligand BDPPZ [(9a,13a‐dihydro‐4,5,9,14‐tetraaza‐benzo[b]triphenylene‐11‐yl)‐phenyl‐methanone] (1) and its polypyridyl hetero‐ and homoleptic Ru(II) metal complexes, [Ru(bpy)2L](PF6)2 (2), [Ru(phen)2L](PF6)2 (3), [Ru(dafo)2L](PF6)2 (4), [Ru(dcbpy)2L](PF6)2 (5) and [RuL3](PF6)2 (6) (where, L = ligand, bpy = 2,2′‐bipyridine, phen = 1,10‐phenantroline, dafo = 4,5‐diazafluoren‐9‐one and dcbpy = 3,3′‐dicarboxy‐2,2′‐bipyridine), have been synthesized and characterized by elemental analysis, UV–vis, FT‐IR, 1H and 13C‐NMR spectra (for ligand), molar conductivity measurements and X‐ray powder techniques. The electrochemical parameters of the substituted ligand and its polypyridyl hetero‐ and homoleptic Ru(II) metal complexes are reported by cyclic voltammetry. UV–vis spectroscopy is used to compare the differences between the conjugated π systems in this ligand and its Ru(II) metal complexes. The polypyridyl hetero‐ and homoleptic Ru(II) metal complexes also tested as catalysts for the formation of cyclic organic carbonates from carbon dioxide and liquid epoxides which served as both reactant and solvent. The results showed that the [Ru(L)3](PF6)2 (6) complex is more efficient than the other Ru(II) complexes for the formation of cyclic organic carbonates from carbon dioxide. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
127.
Yilmaz Yurekli Sacide Alsoy Altinkaya John M. Zielinski 《Journal of Polymer Science.Polymer Physics》2007,45(15):1996-2006
Mutual diffusion coefficients and sorption isotherms of methyl methacrylate (MMA) and butyl acrylate (BA) monomers in methyl methacrylate‐butyl acrylate copolymer (MMA‐BA) have been measured by gravimetric sorption. MMA is found to have higher solubility and diffusion rates in the copolymer than BA. Sorption data for MMA were interpreted using classical Flory‐Huggins thermodynamic theory with a constant interaction parameter (χ). A modified version of this theory has been applied to correlate the sorption data of BA, which exhibit a temperature and concentration‐dependent χ parameter. For MMA, the isotherm data reveal enhanced polymer‐solvent interactions with increasing temperature, while for BA the data indicate a drive toward phase separation with increasing temperature. Despite the difference in thermodynamic behavior, both monomers are found to exhibit Fickian diffusion and the diffusivity data are correlated reasonably well with the Vrentas‐Duda free volume theory. Some deviation between the free‐volume correlation and the experimental data is observed at the lowest temperature and BA concentration examined. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 1996–2006, 2007 相似文献
128.
A.H. Yilmaz M. Kuruoglu 《理论物理通讯》2006,46(4):697-703
The interacting boson model of Arima, Iachello, and co-workers is applied to the even ruthenium isotopes, ^96 Ru -116Ru. Excitation energies, electromagnetic transition strengths, quadrupole and magnetic dipole moments, and △(E2/M1) mixing ratios have been described systematically. Mixed symmetry states are investigated. It is seen that the properties of low-lying levels in these isotopes, for which the comparison between experiment and theory is possible, can be satisfactorily characterized by the Interacting Boson Model-2. 相似文献
129.
130.
Two novel C2-symmetric optically active pyridine-15-crown-5 type ligands containing lipophilic chains at the stereogenic centres, macrocycles 5 and 6, were prepared from (S)-1,2-propanediol and (S)-3-aryloxy-1,2-propanediol for the enantiomeric recognition of amino acid ester derivatives. These novel macrocycles have been shown to be strong complexing agents for primary organic ammonium salts (with K values of up to 1363.5 M?1, ΔGo of up to 17.86 kJ mol?1 and a selectivity ratio of 80:20) by 1H NMR titration method. These macrocyclic host exhibited enantioselective binding towards the l-enantiomer of phenylalanine methyl ester hydrochloride with KL/KD up to 8.57 in CDCl3 containing 0.25% CD3OD. Experimental results have been detailed with molecular dynamic calculations at atomic level concerning the molecular recognition and discrimination properties of a chiral pyridino-15-crown-5. The binding free energies were calculated as ~?25 kJ mol?1. The results indicated that the host binds and discriminates valine salts better than phenylalanine salts. The molecular dynamics, MM/PBSA calculations are consistent with the 1H NMR results. 相似文献