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    Comparison of newly developed hydroxyl-functionalized monodisperse HILIC columns new HILIC column
    (Taylor & Francis Inc, 2017) Dinc, Saliha; Olmez, Saba Samatya; Tuncel, Ali
    In this study, new hydroxyl-functionalized monodisperse polymeric hydrophilic interaction chromatography (HILIC) columns were developed using different derivatization agents. In addition, the influences of derivatization temperature of the best agent and polymer composition on the separation were investigated under HILIC conditions. Monodisperse-porous hydrophilic particles were synthesized by the seeded polymerization method using 3-chloro-2-hydroxypropile methacrylate (HPMA-CL) and ethylene glycol dimethacrylate (EGDMA) monomers. The chloropropyl terminal ends of the poly(HPMA-Cl-co-EGDMA) particles were derivatized with amine group of ethanolamine (EA), diethanolamine, and triethanolamine (TEA) at 80 degrees C through nucleophilic reaction. The performance of synthesized particles was evaluated with the amount of ligand on the particle surfaces, column backpressure, and separation power under HILIC condition. TEA was found to be the best derivatization agent for the separation of toluene, acrylamide, thymine, adenine, and cytosine in respect to resolution factors (>1.5 for all analytes) and theoretical plate numbers (64.562N/m for acylamide). Upon determination of the best ligand, then the effect of different derivatization temperatures and polymer composition on TEA performance was investigated. Of all the tested polymer compositions, the chromatographic performance of TEA-M-80 (the derivatization of TEA at 80 degrees C together with M polymer composition) was found to be the best.
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    Phosphorus doped carbon nanodots particles based on pomegranate peels for highly active dehydrogenation of sodium borohydride in methanol
    (Pergamon-Elsevier Science Ltd, 2022) Olmez, Saba Samatya; Balbay, Asim; Saka, Cafer
    Here, the carbon nanodots were successfully synthesized from pomegranate peels (PPCD). This obtained PPCD was treated by a hydrothermal process with phosphoric acid for P doping (P doped PPCD) and used as a metal-free catalyst to obtain hydrogen(H2) from so-dium borohydride (NaBH4) methanolysis for the first time. The characteristics of the samples obtained by ultraviolet, fluorescence, X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), Transmission electron microscopy (TEM) and Inductively coupled plasma mass spectrometry (ICP-MS) analyses were examined. NaBH4 concentra-tion effect, temperature effect and catalyst reusability experiments were carried out. Using 10 mg of the catalyst with 2.5% NaBH4, an HGR value of 13000 mL min-1g-1 was obtained. The activation energy (Ea) for the P-doped PPCD catalyst was 30.96 kJ mol-1.(c) 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
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    The Novel Polymethacrylate Based Hydrophilic Stationary Phase for Ion Chromatography
    (Oxford Univ Press Inc, 2023) Olmez, Saba Samatya; Kokden, Didem; Tuncel, Ali
    Ion chromatography is widely used as a useful and powerful tool for the analysis of anionic and cationic components found in waters and aqueous media. The performance and selectivity of ion chromatography are based on the stationary phase column packed material. In this study, it is aimed to develop new column material with quaternary ammonium functional group based on monodisperse polymeric particles for ion chromatography and to investigate their chromatographic performance. For the analysis of inorganic anions by ion chromatography, new stationary phases macroporous monodisperse particles based on 3-chloro-2-hydroxy propylmethacrylate-co-ethylene dimethacrylate are obtained as column packing material. 3-chloro-2-hydroxy propylmethacrylate and ethylene glycol dimethacrylate are transformed to porous monodisperse particle form by using glycidyl methacrylate as the seed latex and ethyl benzene as the porogen solvent via micro-suspension polymerization technique. Then macroporous monodisperse particles surface is functionalized by triethylamine so strong anion exchange is obtained for ion chromatography packing material. A series of stationary phases prepared from polymer particles containing different amounts of porogen solvent were tested. The results show that column packing material is successful to separate inorganic anions mixture such as F-, Cl-, NO2-, Br-, NO3- by using the carbonate and bicarbonate solutions as mobile phases.