Master Degree / Yüksek Lisans Tezleri

Permanent URI for this collectionhttps://hdl.handle.net/11147/3008

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Author: search.filters.author.Eroğlu, Ahmet EminSubject: search.filters.subject.Sorbents

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Now showing 1 - 3 of 3
  • Master Thesis
    Preparation of Molecularly Imprinted Polymers for the Solid Phase Extraction of Pyridoxal 5'-phosphate Prior To Hplc Determination
    (Izmir Institute of Technology, 2022) Özyurt, Ömer; Eroğlu, Ahmet Emin
    Three different sorbent materials were prepared for solid phase extraction of pyridoxal phosphate (PLP), namely, carbon sphere based molecularly imprinted chitosan polymer (MICP), magnetite based molecularly imprinted chitosan polymer (MMICP) and silica (sol-gel) based molecularly imprinted polymer (IMIP). The sorbents were characterized by FT-IR, SEM, EDX, XRD, and TGA. The characterization data have shown that, the sorbents were relatively homogeneous, had very fast sorption kinetics and quantitative sorption over a wide range of analyte concentrations (1.0-100.0 mg/L). All the sorbents were found to be selective to PLP in presence of similar compounds; namely, pyridoxamine, nicotinic acid (vitamin B3), pyridoxal and 4-pyridoxic acid. Sorption parameters for each sorbent were optimized. The optimum sorbent amount for 10.0 mL sample volume was found to be 5.0 mg for MICP and 10.0 mg for both MMICP and IMIP. A shaking duration of 30 min was employed in sorption experiments. Among the potential eluents, acetic acid solution (2%, v/v) has shown the best desorption performance for all three sorbents. Method validation was investigated via spike recovery tests on water (ultra-pure, bottled and tap) and artificial serum samples. The recoveries obtained with water samples were greater than 96%, 92%, and 91% for MICP, MMICP, and IMIP, respectively. These results show the potential application of the methodologies for samples with relatively simple matrix. High recoveries (greater than 80%) were also obtained with artificial serum samples, whereas the use of matrix-matched calibration or internal standardization is suggested together with protein precipitation for biological samples with high protein content.
  • Master Thesis
    Sorption of as (v) From Waters by Use of Novel Amine-Containing Sorbents Prior To Hgaas and Icp-Ms Determination
    (Izmir Institute of Technology, 2008) Boyacı, Ezel; Eroğlu, Ahmet Emin
    A novel sorption method utilizing several amine-containing sorbents was developed for arsenic determination in waters by hydride generation atomic absorption spectrometry (HGAAS) and inductively coupled plasma mass spectrometry (ICP-MS).Chitosan, chitosan-immobilized sodium silicate, chitosan-modified macroporous silicate, and aminopropyl triethoxysilane-treated macroporous silicate were among the sorbents investigated for As(V) sorption.Sorption parameters were optimized for As(V) using chitosan and chitosanimmobilized sodium silicate and were then applied in all sorption studies. These parameters, namely, sorption pH, amount of sorbent, reaction temperature, and shaking time were 3.0, 50.0 mg, 25 .C, and 30 min, respectively. The sorption for chitosan under the optimized conditions was 89% (±1) while that for As(III) was lower than 10% at all pHs. In addition, chitosan-modified and amine-modified macroporous silicate demonstrated 88% (±3) and 68% (±12) sorption, respectively. After the sorption, the release of arsenate from chitosan and chitosan-immobilized sodium silicate was realized using two eluents; namely, 2.0% (v/v) acetic acid which dissolved chitosan, and 1.0% (w/v) L-cysteine solution having a pH of 3.0 adjusted with HCl which eluted arsenate by reducing to arsenite. Their respective desorption percentages were 90% (±1) and 100% (±4) for chitosan, and 67% (±2) and 100% (±1) for chitosan-immobilized sodium silicate.The preconcentration study performed using an absolute amount of 150.0 ng As(V) in bottled drinking water at the enrichment factors of 1, 2, and 10 has given 98% (±3), 95% (±2), and 78% (±4) recoveries, respectively. The accuracy of the proposed methodology with chitosan was verified with spike recovery tests for various water types at a concentration of 10.0 .g/L As(V). With matrix-matched calibration, the percentage spike recovery values were determined to be 114 (±4), 112 (±2), 43 (±4), and 0 (±1), for ultrapure, bottled, tap and sea water, respectively. These results have shown the strong suppression effect of the tap and the sea water matrixes.
  • Master Thesis
    Development of Novel Sorbents for Speciation of Inorganic and Organik Selenium Prior To Determination by Atomic Spectrometric Techniques
    (Izmir Institute of Technology, 2011) Demirkurt, Merve; Eroğlu, Ahmet Emin; Eroğlu, Ahmet Emin
    Selenium is an essential trace element forplants, animals and the human body. Hovewer, its possible toxicity at high concentrations necessitates the development of analytical methods for theseparation and determination of the several forms of the element in environmental andbiological systems.In the first part of the study, commercially available and newly synthesized ceria (CeO2) and zirconia (ZrO2) were used for the sorption and speciation of inorganic selenium. Sorption parameterswere investigated for both sorbents for selenite (Se(IV)) and selenate (Se(VI))and the optimized parameters were determined to be 25°C for sorption temperature, 50.0 mg for sorbent amount, 30 min for shaking time for 20.0 mLof 100.0 μgL-1of both species. Therelease of Se(IV) and Se(VI) from the sorbents was realizedusing two eluents, 0.10 M NaOH and 0.10 NH4Cl, respectively. The accuracy of the proposedmethodology was verified with spike recovery tests for various water types spiked with 10.0 μgL-1and 100.0 μgL-1Se(IV) and Se(VI). Spike recovery values were determinedto range between 91% and 97% at 10.0 μgL-1level, and between 97% and 113% at100.0 μgL-1level, for ceria and zirconia, respectively. Moreover, the sorption efficiencies of the newly synthesized sorbentswere compared with those of the commercial sorbents.Ceria and zirconia were shown to be applied in the speciation of inorganic selenium. Sorption studies with nZVI-modified zirconia have demonstrated that the sorbent can be utilized for the speciation of inorganic and organoselenium; namely, Se(IV), Se(VI), Seleno-L-cystine and Seleno-DL-methionine. In the final part of the study, it was shown by column-type equilibration studies that alginate beads modified/immobilized with CeO2 or ZrO2through three different synthesis routes can be used for the sorption and speciation of inorganic selenium.