Master Degree / Yüksek Lisans Tezleri

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

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2010 - 20162

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Author: search.filters.author.Eroğlu, Ahmet EminPublisher: search.filters.publisher.İzmir Institute of Technology

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  • Master Thesis
    Solid Phase Extraction of Ibuprofen in Waters With Molecularly Imprinted Polymers Prior To Hplc-Dad Determination
    (İzmir Institute of Technology, 2016) Ölçer, Yekta Arya; Eroğlu, Ahmet Emin
    Endocrine disrupting compounds (EDCs) attract great attention worldwide due to their undesired effects on human health. Ibuprofen, an example of endocrine disrupters, is a nonsteroidal anti-inflammatory drug (NSAID). In this study, highly selective molecularly imprinted polymers (MIPs) with different morphologies (as monolith and microspherical beads) were synthesized by bulk and precipitation polymerization strategies. MIPs were prepared by using acetonitrile as porogen, methacrylic acid (MAA) as monomer, trimethylolpropane trimethacrylate (TRIM) as crosslinker and the analyte, ibuprofen, as the template. MIPs revealed higher affinity to the template molecule as compared with non-imprinted polymers (NIPs). The MIP prepared by precipitation polymerization was decided to be used as the primary solid phase extraction (SPE) sorbent due to its higher binding capacity towards ibuprofen compared to the MIP prepared by bulk polymerization. Selectivity of MIP to ibuprofen was examined in the presence of structurally related compounds. In this study, a molecular imprinting solid phase extraction (MISPE) methodology was proposed for determination of ibuprofen prior to HPLC-DAD analysis. For this purpose, critical experimental parameters of MISPE method were optimized and determined as follows; solution pH of 8.0, sorbent amount of 25.0 mg for 10.0 mL of 1.0 mgL-1 working solution, sorption time of 30 min and MeOH:H2O (acetic acid, pH 3.0) ratio of 80:20 as desorption solution. The accuracy of the proposed methodology was verified with spike recovery tests for tap and drinking waters and overall recovery was found as 97.4 (± 0.3) for n=3.
  • Master Thesis
    Use of Amine-And Mercapto-Modified Silica as Soild Phase Extraction Sorbent for Speciation of Inorganic Selenium Prior To Determination by Atomic Spectrometric Techniques
    (İzmir Institute of Technology, 2010) Dönertaş, Esen; Eroğlu, Ahmet Emin
    Silica-based sorbents containing amino-, mercapto-, and both functional groups (bifunctional) were prepared and used for the sorption of inorganic Se(IV) and Se(VI) species from waters prior to their determination by atomic spectrometric techniques, namely, inductively coupled plasma mass spectrometry (ICP-MS) and hydride generation atomic absorption spectrometry (HGAAS). The presence of the functional groups on the surface of the silica was demonstrated by using several characterization techniques such as scanning electron microscopy (SEM), solid-state NMR spectroscopy, thermo gravimetric analysis (TGA), elemental analysis and Brunauer-Emmett-Teller (BET) surface area analysis. Amine-modified silica was found to be selective towards Se(VI) at pHs 2.0 and 3.0 whereas mercapto-modified silica retains Se(IV) over a wide range from acidic regions to pH 4.0. Bifunctional silica, on the other hand, possesses the good features of the two sorbents; it can be used in the separate sorption of Se(IV) or of both Se(IV) and Se(VI) species. Acidic pHs (<1.0) are convenient for the sorption of Se(IV) alone where no sorption is observed for Se(VI). Alternatively, pH can be adjusted to 2.0 or 3.0 and Se(IV) and Se(VI) can be retained simultaneously. Desorption of selenium species from the sorbents was realized with two different eluents; 0.2% (m/v) KIO3 in 1 M HCl was used for Se(IV) and 2.0 M HCl for Se(VI). The efficiency of the proposed sorbents was demonstrated through spike recovery tests carried out with bottled drinking and tap water samples and the percentage recoveries were found to change between 82.2 ± 7.1 and 109.4 ± 3.6 for Se(IV). For Se(VI), mechanically mixed amino- and mercapto-modified (MIX) silicas in (1:1) ratio has shown the best performance with percentage recoveries of 87.1 ± 3.6 and 74.5 ± 6.6 for the spiked bottled drinking and tap water samples, respectively.