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.Molecularly imprinted polymers

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Now showing 1 - 4 of 4
  • Master Thesis
    Development of Molecularly Imprinted Solid Phase Extraction Method for the Detemination of Vitamin D Derivatives
    (Izmir Institute of Technology, 2022) Tosun Kurtalan, Hazal; Eroğlu, Ahmet Emin; Eroğlu, Ahmet Emin
    Vitamin D, also known as the sunshine vitamin, is both a micronutrient and a prohormone. There are two structurally different forms of vitamin D: vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol). Both forms can be taken into the body through food or dietary supplements. In addition, ergocalciferol and cholecalciferol can be synthesized non-enzymatically by UVB radiation of sunlight from provitamin forms, which are ergosterol and 7-dehydrocholesterol. In this study, a methodology based on molecularly imprinted solid phase extraction (MISPE) is intended prior to the determination of D2 and D3 by HPLCDAD. In accordance with this purpose, precipitation and sol-gel polymerization methods were used to synthesize molecularly imprinted polymers (MIPs) and nonimprinted polymers (NIPs). Also, different templates, monomers, crosslinkers, and their ratios were tried in the synthesis of MIPs/NIPs by precipitation polymerization. Among all syntheses, MIP, which was synthesized using vitamin D2 as template (T), 4- vinylpyridine (4-VP) as monomer (M), ethylene glycol dimethacrylate (EGDMA) as crosslinker (C) at a molar ratio of 1:6:30 (T:M:C), enabled the co-determination of vitamin D2 and D3. It selectively worked on the vitamin D prohormone group compared to both NIP and commercial solid phase extraction (SPE) sorbents in the presence of other structurally related compounds. The critical experimental parameters of the MISPE method were optimized for the analyte concentration of 1.0 mgL-1 and determined as follows: 8 hours as the sorption time, 5.0 mg as the sorbent amount, 5.0 mL as the sample solution volume, methanol as the eluent, and 24 hours as the desorption time. A matrix-matched calibration curve with optimized parameters was proposed. The applicability of the developed MISPE method was confirmed by analyzing the sample of vitamin D3 supplementation and overall recovery was found as 95.97% (±1.84) for n=2.
  • Master Thesis
    Preparati̇on of Fe and Fe-Ni Based Molecularly Imprinted Polymer for Solid Phase Extraction of Salicylic Acid
    (01. Izmir Institute of Technology, 2021) Bildik, Zeynep; Eroğlu, Ahmet Emin
    Aspirin is the most preferred pain reliever among the people. Salicylic acid (SA) is the drug active ingredient of aspirin and has an antipyretic, analgesic, and anti-inflammatory properties. It is also used in the treatment of acne, fungus, varicose veins, and calluses. The aim of this project is to prepare Fe and Fe-Ni based molecularly imprinted polymers (MIPs) for solid phase extraction of salicylic acid and then determine it with HPLC-DAD. MIPs were prepared by using methanol as porogen, 4- vinyl pyridine as monomer, ethylene glycol dimethacrylate cross linker and the analyte, salicylic acid, as the template. Fe and Fe-Ni is used to prevent the hydroxyl and carboxyl groups in the structure of salicylic acid from forming hydrogen bonds between themselves. In this study, a magnetic molecular imprinting solid phase extraction (MMISPE) methodology was proposed for determination of salicylic acid to HPLC-DAD analysis. For this goal, critical experimental parameters of MMISPE method were optimized and determined as follows; sorbent amount of 25.0 mg for 10.0 mL of 5.0 mgL-1 working solution, sorption time of 30 min and MeOH: Acetic acid (9:1) as desorption solvent. The proposed method was repeated with same sorbent and MIPs show quantitative sorption in three times. For characterization of MIPs and NIPs, EDX and XRD analysis was done. In XRD diffractogram, the peaks are relatively low intensities indicate that the material is mostly amorphous. Also, Fe and Ni peak cannot observe because of the trace amount of Fe and Ni in the polymer in the EDX graph.
  • Master Thesis
    Development of Novel Columns for Determination of Various Ss-Blockers by Capillary Electrochromatography
    (Izmir Institute of Technology, 2018) Gürel, Elif; Eroğlu, Ahmet Emin
    ß-blockers are one group of the most widely used drugs to treat heart failure, high blood pressure and abnormal heart rhythms. The purpose of this study was to develop capillary columns of stationary phases from molecular imprinting and sol-gel methodology for the determination of ß-blockers prior to capillary electrochromatography (CEC) analysis. In the first part of the study, molecularly imprinted organic based polymers (MIPs), silica-based molecularly imprinted polymers (SMIPs) and silica-based sorbents were developed, characterized and utilized for sorption of metoprolol, an example of ß-blockers. The three different types of sorbents were studied as stationary phases of capillary column. Critical parameters on sorption of metoprolol were investigated. In the second part, the subsequent studies were concentrated on the preparation new capillary column for separation and determination of metoprolol for CEC analysis. The performance of three different types of sorbents was compared. Molecularly imprinted organic polymers show higher sorption and selectivity towards metoprolol as compared with the other sorbent types. The preparation of stationary phases of capillary columns with molecular imprinted organic polymers was proposed for determination of metoprolol prior to CEC analysis. After stationary phase optimization studies, an open tubular column was prepared and its performance was examined.
  • Master Thesis
    Development of Novel Columns for Determination of Various Diuretics by Capillary Electrochromatography
    (Izmir Institute of Technology, 2018) Yaşar, Cemre; Eroğlu, Ahmet Emin
    Diuretics are active pharmaceutical compounds that are used for the treatment of edema, cirrhosis, hypertension and renal failure. World Anti-Doping Agency has announced diuretics as banned compounds. Because they are used as a masking and doping agent. In this study, target compounds are therapeutically important groups of this active pharmaceuticals; namely thiazides (bendroflumethiazide, chlorothiazide, hydrochlorothiazide). Sol-gel chemistry and molecularly imprinted polymers (MIPs) methodology were offered for preparing the column for capillary electrochromatography (CEC) for determination of thiazides. Modified silica sol-gel (amine and phenyl modified) and MIPs were synthesized through different routes (inorganic and organic form) as filling materials for capillary columns. Materials which were filled into the column were selected by the help of sorption studies prior to CE-DAD analysis. For this purpose, critical experimental parameters of CE-DAD were optimized and determined as follows; background electrolyte type of borate buffer (10mM) and pH of 9.4, voltage of 25 kV, cassette temperature of 30℃. Limit of detection (LOD) were calculated as between 0.20 mg L-1 and 0.30 mg L-1. Limit of quantification (LOQ) was found as between 0.44 mg L-1 and 0.99 mg L-1. Finally, sorbents having best sorption capacity towards the analytes were prepared as a stationary phase of capillary column and analysis was done with CEC-DAD.